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Optometry in Practice
The continuing education journal of the College of Optometrists
2009 Volume 10 Issue 1 pages 1 – 32
ISSN 1467-9051
A peer-reviewed journal
published quarterly
CET Information
An MCQ answer sheet is inserted at the back of this issue. Subscribers who are not members of
the College of Optometrists can download a copy of the MCQ answer sheet at www.distancelearning-uk.net.
You can mail or fax the MCQ answer sheets to DLL Administration, PO Box 6, Skelmersdale,
Lancashire WN8 9FW. Contact tel: 01695 554 209 fax: 01695 554 210
College members can answer the MCQs online via the College website members’ area. If you
experience any difficulty submitting MCQs online, please contact [email protected] or telephone 0207 766 4399
The deadline for receipt of MCQ answer sheets is 5pm 13 May 2009.
A total of 6 CET credits are available.
The breakdown for each paper is printed at the top of the list of questions, with the reference.
Please note you do not have to complete every section of the answer sheet.
Credits can be given for individual papers.
Information for Authors
A Guide for Authors is available from the publishing office (see page i).
Pass mark 60%. CET credits available: papers with 21 MCQs 4 credits, 15 MCQs 3 credits, papers with
12 MCQs 2 credits, papers with 6 MCQs 1 credit.
Optometry in Practice
THE COLLEGE OF OPTOMETRISTS
Editor-in-chief
Stephen Parrish BSc PhD FCOptom MIET FHEA
Visiting Professor, Anglia Ruskin University, Cambridge and City University, London, College of Optometrists
Examiner and Assessor
Editorial Board
Dr Maria Dengler-Harles
Paul Carroll
BSc MCOptom MBA
Visiting Fellow, Anglia Ruskin University, Cambridge,
Director of Professional Services,
Specsavers Opticians, College of Optometrists
Examiner and Pre Reg Supervisor
BSc PhD MCOptom
Principal Optometrist, University Hospital Aintree, College
of Optometrists Examiner, PQE Consultation Committee
member, Pre Reg Supervisor
Dr Russell Watkins
Prof. Jonathon Jackson
MB ChB(Hons) BSc(Hons) PhD FHEA
Academic Specialist Registrar, Department of
Histopathology, Hull Royal Infirmary
BSc PhD MCOptom FBCLA
Principal Optometrist, Department of Ophthalmology, Royal
Victoria Hospital, Belfast; Visiting Professor, Department of
Biomedical Sciences (Vision Sciences), Queen’s University,
Belfast and Head of Professional Services (GOS), Central
Services Agency, Belfast
Prof. David Edgar
BSc FCOptom
Professor of Clinical Optometry, Department of
Optometry and Visual Science, City University, London
College of Optometrists Examiner
Dr Clare O’Donnell
PhD MCOptom FAAO
Lecturer in Optometry, Faculty of Life Sciences, University
of Manchester and College of Optometrists Examiner
Distance Learning Limited
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email: [email protected]
Frequency: Published quarterly in February, May,
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© 2008 The College of Optometrists
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i
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Optometry in Practice Vol 10 (2009) ii
Editorial
Professor ST Parrish BSc PhD FCOptom MIET FHEA
Visiting Professor, Anglia Ruskin University, Cambridge and City University, London, College of Optometrists
Examiner and Assessor
Welcome to the first issue of Optometry in Practice for 2009, the last year in the current CET cycle; this issue provides
opportunity for a further 6 CET points.
In the wake of meticillin-resistant Staphylococcus aureus (MRSA) and other infectious diseases, there is an increasing
awareness of the need for infection control within the healthcare arena. This concern goes beyond the confines of
hospitals and health institutions and extends into all areas where patient safety is an issue. Clearly, optometry is not
excluded from these considerations and whilst many may have thought that our lack of involvement with invasive
procedures might exempt us from such matters, it will be clear from the article on infection control by Blakeney that this
is certainly not the case. Infection control now forms part of our contract to provide NHS services and the profession will
need to embrace this topic in the modern world.
Whilst infection control may be a new concept for many of us, the patient presenting with headaches will be all too
familiar. In his review of migraine, Larner discusses the various presentations of both migraine and other headaches,
together with their associated pathophysiology and causes. I am sure that this will be of interest and value to all of us
who are presented with such patients; for many of us this will be on almost a daily basis.
Although recent changes in infection control have been influenced largely by the spread of MRSA and Clostridium difficile,
changes in healthcare regulations have undoubtedly been influenced by cases such as the Shipman inquiry and others.
In the first part of his series on legal cases, Kapoor sets out recent legislative changes and illustrates difficult situations
that can occur in practice. This should serve to remind us all of the need to be aware of current guidance and to
implement it wisely when required.
I hope you will find the articles both enjoyable and helpful in practice as well as an opportunity for obtaining CET points.
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© 2009 The College of Optometrists
Optometry in Practice Vol 10 (2009) 1–12
Infection Control in Optometric Practice
Susan Blakeney
PhD LLM LLB BSc FCOptom
Optometric Adviser, College of Optometrists, London
Date of acceptance 3 February 2009
Introduction
It therefore not only makes good practice sense, but also
good business sense to put procedures in place to reduce
these risks.
Although infection control has always been important for
the safety of both the patient and practitioner, awareness
of the issues has become greater in recent years with
concern about the spread of infections caused by meticillin
(formerly methicillin)-resistant Staphylococcus aureus
(MRSA) and Clostridium difficile. According to the
Department of Health for England, the term ‘healthcareassociated infections’ (HCAIs) encompasses any infection
by any infectious agent acquired as a consequence of a
person’s treatment by the National Health Service (NHS)
or which is acquired by healthcare workers in the course of
their NHS duties. The prevention and control of HCAIs are
high priorities for all parts of the NHS. It is of equal
importance for healthcare providers in the independent
and voluntary sectors (Department of Health 2008a).
Risk Management
A risk management strategy relating to infection control
would include firstly identifying the hazards posed to both
practitioner and patient from optometric (and dispensing)
activities. The risk to the patient would include acquiring
infection from the practitioner and from other patients via
the practitioner or equipment/drugs/solutions used. The
risk to the practitioner would include acquiring infection
from the patient (and possibly other members of staff!).
The degree of risk of each activity (eg dispensing, the
routine eye examination − it may be helpful to break this
into parts, eg contact versus non-contact tonometry − and
contact lens fitting/aftercare) should be quantified. For
further information on how to quantify risks, see the
College of Optometrist’s module on risk management
(College of Optometrists 2004).
As well as being part of a practice’s risk management
policy it is now also a requirement of the General
Ophthalmic Services contract in England that the
contractor has ‘appropriate arrangements for infection
control and decontamination’ (SI 1185 of 2008 Schedule
1, para 5(1)(a)). Failure to do so could jeopardise the
contract. Good hygiene measures will not only protect the
patient from contracting an avoidable infection, but also
do the same for the practitioner. Under health and safety
legislation employers are responsible for ensuring that
workplace hazards are identified, risk-assessed and
appropriate precautions are taken to protect against them.
This includes protecting the practitioner from unnecessary
infection.
Once quantified, appropriate action can be taken to
manage these risks. This would include having appropriate
hand hygiene measures in place (see below), ensuring that
contact lens solutions are in date and opened bottles are
replaced regularly (this is facilitated when either the date
on which they are opened or, better, the date by which they
must be discarded is written on them) and having
appropriate decontamination procedures for ophthalmic
equipment that is not disposable, including having
appropriate procedures for decontaminating surfaces such
as slit-lamp chin and forehead rests and visual field
equipment, and ensuring that the clinical areas are clean
and tidy.
It is easy to think of infection control as just another
burden on busy practitioners, but as well as the human
cost of subjecting patients and practitioners to
unnecessary infections if robust procedures are not
followed, there is also the financial cost. Patients may
decide to sue practitioners if they contract an infection
which they feel has been caused by the practitioner’s
negligence, and practitioners may be forced to take time
off work as the result of contracting an avoidable infection.
Once these procedures have been put in place,
practitioners should ensure that all staff are trained about
the risks and the measures that have been put in place to
control these. The final step is for the practitioner to audit
the procedures after a suitable period of time to assess
Address for correspondence: Dr S Blakeney, The College of Optometrists, 42 Craven Street, London WC2N 5NG, UK.
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© 2009 The College of Optometrists
S Blakeney
act as a reservoir of MRSA. Healthy people are unlikely to
develop an MRSA infection, although they may become
colonised (Wilson 2006 p. 109). The most important route
of transmission of MRSA is on the hands of staff who care
for the patient. The inanimate environment is not
generally a reservoir for MRSA (except possibly in burns
units) (Mylotte 1994). Airborne spread is theoretically
possible, but unlikely unless the patient is shedding
excessive amount of skin scales and the standard of
cleaning is very low (Barrett et al. 1993, Mylotte 1994,
Strausbaugh et al. 1996). Although MRSA can be isolated
from objects such as computer keyboards and door
handles, there is little evidence that contamination of the
environment plays a significant part in the transmission of
infection between patients. Contamination from the
environment will not be transferred to patients provided
hands are decontaminated before contact with patients
(Wilson 2006 p. 110). There is no evidence to suggest that
the use of masks decreases staff nasal acquisition rates of
MRSA (Casewell 1986). It has been suggested that good
all-round standards of infection control practice are more
important than specific radical policies in dealing with
endemic MRSA (Barrett et al. 1993).
whether the procedures are being adhered to. If not, then
investigations should be conducted to find out why (eg
does everyone, including locum staff, know where the
antiseptic surface wipes are kept?).
Infection is caused by pathogenic or disease-causing
microorganisms. To understand how to control infection it
is therefore important to understand what the different
types of microorganisms are, what they need to survive and
how they get into (or on to) the human body. Many of the
microorganisms that cause illness usually live on us or in
us quite harmlessly. Problems occur when they move from
where they should be (eg outside the body, on the skin) to
where they shouldn’t be (eg inside the body via a surgical
wound), where they can cause harm.
Types of Microbes
Microbes are found almost everywhere and are able to
survive in almost every conceivable environment.
Bacteria
Fungi
Bacteria are single-celled organisms. They need water to
grow and most die rapidly in the absence of water. Some
bacteria are more resistant to drying out or are able to
form spores (eg C. difficile). The spores may be able to
survive for hours or even months without water,
recommencing multiplication with a supply of moisture.
Some bacteria use oxygen for respiration, whilst others use
fermentation and are anaerobic. Some bacteria can use
either respiration or fermentation to make energy,
changing the method according to their environment.
Those that grow in association with humans multiply
rapidly at around body temperature, but some bacteria can
withstand temperatures of 100°C and others can grow at
temperatures as low as −10°C. Most bacteria prefer to live
in approximately neutral conditions and cannot survive if
the pH of the solution is too acid or too alkaline.
Fungi are plants but they lack the chlorophyll required
for photosynthesis. They can survive with relatively
little moisture.
Protozoa
Protozoa are organisms, many of which have complex life
cycles. They can move in at least one of their life cycle
stages and some form thick-walled, dormant cysts. One
example that can affect the eye is Acanthamoeba, which is
present in almost every environment, including soil, dust
and water. It can also be found in the nose and throat of
healthy people. Acanthamoeba keratitis, although rare,
can be blinding. Around 85% of cases are associated with
contact lens use. Acanthamoeba cysts can be difficult to
kill and so it is important for practitioners to check that
disinfectants such as contact lens solutions are effective
against them and that patients immerse their lenses in the
disinfectant for the amount of time required for adequate
disinfection to occur. The risk factors for Acanthamoeba
infection in contact lens wearers are: the use of tap water
during lens care; wearing lenses without goggles whilst
swimming, showering or in hot tubs; the use of ineffective
lens care solutions and failure to follow lens
care instructions (for further information see
http://www.bcla.org.uk/acanthamoeba.asp).
Much publicity has surrounded outbreaks of
Staphylococcus aureus. S. aureus is commonly found on
the skin and in the nose of healthy people. It can cause a
variety of infections ranging from mild skin infections
(boils and abscesses) to serious systemic infection. MRSA
causes the same type of infection as sensitive strains of S.
aureus. Hospitalisation is a major risk factor for the
acquisition of MRSA. In long-term care settings, although
the risk of transmission and serious infection is lower
(because residents are generally more healthy and have
fewer invasive devices than hospital patients), patients may
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Infection Control in Optometric Practice
Viruses
Microorganisms are unable to infect a host unless they are
transmitted to the host. They cannot fly or jump from one
host to another and can only be transmitted by another
means. The main routes of transmission in optometric
practice will be via airborne particles such as dust or
respiratory droplets in a sneeze (facilitated by the close
proximity of the practitioner to the patient in both the
consulting room and dispensing area) or from another
infected individual via the practitioner’s hands or
equipment. Both of these mechanisms may also act to
infect the practitioner, and so good infection control
will help to avoid the optometrist contracting infections
from patients.
Viruses are not living organisms and are simply a piece of
nucleic acid surrounded by a protein coat and sometimes
a lipid envelope. They are extremely small (ranging from
approximately 20 to 250nm in diameter, compared with
the average bacterial cell diameter of 1000nm). They can
only multiply inside living cells. This is done by receptors
on the viral surface recognising specific receptors on the
surface of particular cells in the host. The viral nucleic acid
then enters the nucleus of the host cell and instructs the
cell’s own replication mechanism to copy the viral nucleic
acid. The virus components are then assembled in the
cell’s cytoplasm and new viruses are released either by
budding out of the cell membrane or by causing the cell to
rupture. Most viral illnesses are short with a complete
recovery because, although the host cells that are infected
by the virus are destroyed, these cells are rapidly replaced.
Microorganisms need to have a reservoir where they live,
grow and multiply. This may be in the environment (eg a
water tank, contact lens solution) or it may be on a person.
Most bacteria die without the presence of water, so in
clinical environments environmental reservoirs are most
likely to occur where moisture is present. However,
infection may occur from dry surroundings too and it is
also important to ensure that other potential reservoirs
such as dusty surroundings are reduced as much as
possible. Neely & Maley (2000) found that staphylococci
(including MRSA) and enterococci can survive for days to
months after drying on commonly used hospital fabrics
and plastic. C. difficile can form spores which may survive
in dust and epidemic strains of MRSA may be particularly
good at surviving in dust (Wagenvoort et al. 2000).
Rampling et al. (2001) found that, in addition to standard
infection control measures, thorough and continuous
attention to ward hygiene and removal of dust was needed
to terminate a prolonged outbreak of MRSA infection on a
general surgical ward. It can therefore be concluded that
preventing the accumulation of dust on surfaces and floors
can be an important infection control measure (Cartmill
et al. 1994). C. difficile spores are capable of persisting on
hard surfaces for as long as 5 months (Gerding
et al. 2007).
Routes of Transmission
The human body is densely populated by a wide variety of
microorganisms which use it as their habitat. These are
called commensals and they live on the host without
causing any harm. Different organisms are present in
different areas of the body and in many cases both the
organism and the human benefit from the relationship.
The key benefit to the host is that the presence of the
normal flora prevents other harmful microorganisms from
colonising the habitat. According to Noble (1975) humans
disseminate more than 107 particles of skin every day,
although bathing or showering will remove many of these
mechanically. Natural walking movements have been found
to release about 104 skin flakes (squames) per minute.
Approximately
10%
of
squames
carry
viable
microorganisms. This means that 106 skin squames
(flakes) containing viable microorganisms (such as S.
aureus) are shed daily from normal skin (Noble 1975). The
larger particles of dust settle within a few minutes on to
exposed horizontal surfaces, but small particles may
remain airborne for several hours and microbes carried on
them may be inhaled into the respiratory tract or settle
into wounds (Wilson 2006 p. 40). Patient gowns, bed linen
and bedside furniture as well as other objects in the
patient’s immediate vicinity can therefore easily become
contaminated with patient flora. In skin disease, such as
eczema and psoriasis, the skin may be densely colonised by
S. aureus. These organisms are then dispersed on skin
scales and such persons may contaminate their
environment with these pathogens. The hair can carry S.
aureus but opinion is divided as to the role of the hair in
dispersal (Noble 1975).
Viruses cannot grow without living cells to support them
and most viruses are fragile and cannot survive outside a
living cell for long. However, some can survive on hands or
surfaces before being transmitted to a new host. Viruses
are fairly resistant to some disinfectants such as
chlorhexidine and prevention of infection caused by viruses
can be extremely difficult.
Microbes causing an infection may be acquired from
another person or from the environment. This is called an
exogenous source and the transmission is referred to as
cross-infection. An example would be conjunctivitis caused
by contaminated contact lens solution or infected contact
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S Blakeney
objects or the environment. They are particularly easily
acquired on the hands when the object touched is moist
(Marples & Towers 1979), so although transient flora can
be acquired by touching dry patients or objects, particular
care needs to be taken when dealing with moist, heavily
contaminated substances such as body fluids. Transient
flora are generally easily removed by good hand hygiene.
Resident flora rarely cause disease and are of minor
significance in routine clinical situations because these
organisms are not readily transferred to other people or
surfaces and most are of low pathogenicity. However, some
resident bacteria could cause infection if they are
introduced during invasive procedures into normally
sterile body sites or on to particularly vulnerable patients
such as neonates (Wilson 2006 p. 158). These instances
are unlikely to occur in routine optometric practice, so the
main focus is to remove the transient flora.
lens, or MRSA passed from one patient to another by
healthcare staff. Alternatively an infection may occur when
a microorganism which is already on the host enters a
different site on the host and causes infection. An example
would be the transmission of herpes simplex from a cold
sore on the patient’s face to the patient’s cornea, causing
a dendritic ulcer. This is called endogenous or selfinfection.
Principles of Infection Control
Intact skin is an effective barrier against many infections
entering the body. It is therefore important that any cuts
are covered with a waterproof dressing. Skin should also be
dried properly and a hand cream used if necessary to avoid
cracked or damaged skin which may become infected.
The National Institute for Health and Clinical Excellence
(NICE) has produced guidelines for preventing HCAIs in
primary and community care. The summary of the
recommendations includes the following evidence-based
standard principles on hand hygiene (NICE 2003).
Recognising the modes of infection transmission is the key
to managing and reducing this. The various modes of
transmission will be discussed in turn.
Indirect contact via healthcare worker (ie
from one infected individual to another via a
healthcare worker such as the optometrist)
Hand hygiene
• SP1: Hands must be decontaminated immediately
before each and every episode of direct patient contact
or care and after any activity or contact that could
potentially result in hands becoming contaminated.
• SP2: Hands that are visibly soiled, or potentially grossly
contaminated with dirt or organic material, must be
washed with liquid soap and water.
• SP3: Hands must be decontaminated, preferably with an
alcohol-based handrub unless hands are visibly soiled,
between caring for different patients or between
different care activities for the same patient.
• SP4: Before regular hand decontamination begins, all
wrist and ideally hand jewellery should be removed.
Cuts and abrasions must be covered with waterproof
dressings. Fingernails should be kept short, clean and
free from nail polish.
• SP5: An effective hand-washing technique involves three
states: preparation, washing and rinsing, and drying.
Preparation requires wetting hands under tepid running
water before applying liquid soap or an antimicrobial
preparation. The handwash solution must come into
contact with all of the surfaces of the hand. The hands
must be rubbed together vigorously for a minimum of
10−15 seconds, paying particular attention to the tips
of the fingers, the thumbs and the areas between the
fingers. Hands should be rinsed thoroughly before
drying with good-quality paper towels.
The main weapon against this route of transmission is
good hand hygiene. This is recognised by the National
Patient Safety Agency (NPSA) in its ‘cleanyourhands’
campaign (www.npsa.nhs.uk/cleanyourhands/). Although
the significance of hands as vectors of cross-infection was
not fully appreciated until the 1960s, the importance of
hand washing was first clearly demonstrated by the
Hungarian physician Semmelweis in the 1840s.
Semmelweis (1818–1865) found that the incidence of
puerperal fever could be drastically cut by use of handwashing standards in obstetrical clinics (Newsom 2001,
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5116a1
.htm). He thought that the medical students were
transmitting the disease on their hands from the cadavers
that they were dissecting. Semmelweis found that the
introduction of hand washing with chlorinated lime
solutions for the students who had performed autopsies
reduced the incidence of fatal puerperal fever dramatically.
Although Semmelweis’ work was not widely accepted at
the time, it was supported by Louis Pasteur’s (1822–1895)
germ theory of disease.
There are two categories of microorganisms present on the
skin: the transient and the resident flora. The transient
flora consists of microorganisms that are acquired on the
surface of the skin through contact with other people,
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Infection Control in Optometric Practice
Alcohol handrubs have been shown to reduce the incidence
of healthcare-acquired infection and can increase
compliance with hand hygiene. They have been found to be
more effective than both soap and water and antiseptic
soap solutions at removing rotavirus from the hands
(Bellamy et al. 1993) and in most situations they can be
used as an alternative to routine hand washing with soap
and water providing hands are not visibly soiled (Wilson
2006 pp. 158–159). A non-randomised controlled trial was
conducted where the use of alcohol hand gel was
introduced to a long-term elderly care facility. This
demonstrated a reduction of 30% in healthcare-acquired
infection over a period of 34 months when compared to a
control unit (Fendler et al. 2002). A useful review of the
benefits of waterless handrubs can be found in
Widmer (2000).
• SP6: When decontaminating hands using an alcohol
handrub, hands should be free from dirt and organic
material. The handrub solution must come into contact
with all surfaces of the hand. The hands must be rubbed
together vigorously, paying particular attention to the
tips of the fingers, the thumbs and the areas between
the fingers, until the solution has evaporated and the
hands are dry.
• SP7: An emollient hand cream should be applied
regularly to protect skin from the drying effects of
regular hand decontamination. If a particular soap,
antimicrobial handwash or alcohol product causes skin
irritation an occupational health team should
be consulted.
It is important to ensure that, as well as being thoroughly
washed, hands are also dried properly using disposable
paper towels. Hot-air hand dryers are not generally
recommended because most are not very efficient and take
longer than using a paper hand towel. This means that the
hands may not be dried properly, resulting in chapped skin.
The other advantage of using paper towels rather than hotair dryers is that, if it is used effectively, a paper hand towel
can remove additional transient organisms missed during
washing (K Hawker, personal communication). Reusable
cotton towels should not be used because they only replace
organisms on the hand with organisms from the towel
(Lawrence & May 2003). Towels should be disposed of via
a foot-operated pedal bin or an open-topped bin without a
lid. This will prevent staff from touching bin lids and avoid
the recontamination of their hands.
The antimicrobial activity of alcohols is caused by their
ability to denature proteins and alcohol solutions
containing 60−95% alcohol are most effective.
Interestingly, higher concentrations are less potent
because proteins are not denatured as readily in the
absence of water (Ali et al. 2000). The alcohol content of
solutions may be expressed as a percentage by weight
(w/w), which is not affected by temperature or other
variables, or a percentage by volume (vol/vol), which can
be affected by temperature and other variables. Alcohol
concentrations in antiseptic handrubs are often expressed
as a percentage by volume. Kampf & Hollingsworth (2008)
found that an (85% w/w) ethanol-based hand gel had a
broad spectrum of bactericidal activity which included the
most common species causing nosocomial infections
(including MRSA, Pseudomonas aeruginosa and the
vegetative form of C. difficile). It is important to recognise
that, although the hand gel was effective against the
vegetative form of C. difficile, decontamination of hands
using such a rub alone would not be sufficient when
contamination of hands with C. difficile is expected
because the organism can also exist in spore form and C.
difficile spores are not killed by alcohol (Gerding et al.
2007). Alcohols have very poor activity against bacterial
spores, and certain non-lipophilic viruses, although certain
lipophilic viruses (eg herpes simplex, human
immunodeficiency virus (HIV), influenza virus) are
susceptible to alcohols when used at appropriate
concentrations (Ali et al. 2000). Alcohols are effective
against fungi, but little is known about their effectiveness
against persistent stages of protozoa (Ali et al. 2000).
It is helpful to have a poster detailing hand-washing
technique. One such poster has been produced by the
World Health Organization and is reproduced in the
Guidance on Infection Control published by the College of
Optometrists (2009a). When washing hands, common
areas that are missed include the thumb, fingertips and
between the fingers. One way to check the effectiveness of
hand-washing technique is firstly to use a ultraviolet
fluorescent gel to cover the hands and then a lightbox to
see how much has been washed off using the hand-washing
technique. This is often done as part of infection
control training.
An inadequate supply of hand-washing facilities may
decrease the frequency with which practitioners wash their
hands. Hand-washing facilities can now be installed in
almost any location, including where no plumbing is
available (see for example www.tealwash.com).
The US Centers for Disease Control (CDC 2002) advise
that washing hands with soap and water after each use of
an alcohol handrub is not necessary and indeed is not
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S Blakeney
infectious disease should take additional care not to infect
their patients, and those who examine patients who are
known to be infectious should similarly consider taking
additional precautions. This could include, for example,
wearing a face mask if appropriate. It is now recognised
that, unless the mask fits closely around the mouth and
nose, air is inhaled and exhaled around its edge and is
therefore not filtered. This is particularly the case if the
fabric in the mask collects moisture, as this further
impedes the flow of air through the mask (Wilson 2006
p. 164). Research has not proved that face masks prevent
the transmission of HCAIs in routine procedures (Pratt et
al. 2007) so the routine use of masks is not recommended
or needed unless there is a serious respiratory risk involved
(eg tuberculosis within the first 2 weeks of treatment or
pandemic flu, where there is no vaccination available).
Even then masks are only recommended when the
practitioner is within 1 metre of an infected patient. If
healthcare practitioners have an infectious respiratory
disease they should not be working!
recommended because it may lead to dermatitis. Some
people may feel a build-up of emollients (moisturisers) on
their hands after repeated use of alcohol hand gel and so
some manufacturers recommend washing hands with soap
and water after 5−10 applications of a gel.
Use of gloves
NICE (2003) recommends that gloves are worn for invasive
procedures, contact with sterile sites and non-intact skin
or mucous membranes, and for all activities that have been
assessed as carrying a risk of exposure to blood, body
fluids, secretions or excretions, or sharp or contaminated
instruments. It is unlikely that most of these situations will
occur in routine community optometric practice, with the
exception of exposure to the patient’s tears and each
situation should be assessed on its own merits. NICE also
recommends that gloves should not be worn unnecessarily
as their prolonged and indiscriminate use may cause
adverse reactions and skin sensitivity. Gloves must be
disposed of after each patient use and hand hygiene
measures are necessary before wearing, and after the
removal of, the gloves.
Airborne particles
If gloves are worn, it should be recognised that they do not
provide complete protection against hand contamination
and bacterial flora colonising patients may be recovered
from up to 30% of healthcare workers who wear gloves
during patient contact (Olsen et al. 1993, Tenorio et al.
2001). Hand washing is therefore necessary after glove
removal. The evidence as to how likely people are to
perform hand hygiene whilst gloves are being used is
conflicting. One study found that people who wore gloves
were less likely to wash their hands upon leaving a patient’s
room (Larson 1983), although three other studies found
that people who wore gloves were substantially more likely
to wash their hands after patient care (Meengs et al. 1994;
Thompson et al. 1997; Zimakoff et al. 1993). Thompson et
al. (1997) found that, although healthcare workers used
gloves, they did not change or remove them as often as
required by their infection control procedures. They also
note that, whilst some may argue that it is best to adopt
ideal infection control guidelines, practical guidelines that
focus on those body substances known to carry significant
risk for disease transmission should be designed.
Microorganisms may attach themselves to droplets emitted
by a sneeze or cough, or to particles of dust from the
environment. Dust is largely composed of skin squames
and fibres released from clothing and other fabrics. Whilst
the larger particles of dust may settle on to exposed
horizontal surfaces within a few minutes, the smaller
particles may remain airborne for several hours and
microbes that are carried on them may be inhaled or settle
into wounds. Most bacteria cannot survive for long on dust
particles, but their spores may survive for many months. As
well as harbouring such organisms, dust may also be an
irritant which could induce sneezing. This may well, in
turn, dislodge the dust and make it more likely to be
inhaled. It is therefore important to ensure that the
environment is kept clean and free from dust as much as
possible. It is self-evident that spills of body fluid (which
are extremely unlikely to occur in optometric practice)
must be cleaned and disinfected.
The Department of Health for England is encouraging
respiratory and hand hygiene using its ‘Catch it, Bin it, Kill
it’ campaign, the second phase of which began on 24
November 2008 and runs until early 2009 (Department of
Health 2008b). The aim is to reduce the spread of germs,
particularly during the cold and flu season. The campaign
urges that:
As well as passing infection from one patient to another via
the practitioner, practitioners should also be aware of the
dangers of contracting or transmitting infections directly
from or to their patients (as may be the case for example
when patients come in for an eye examination when they
are off sick from work!). The strategies to reduce this
direct transmission of infection are the same as for
indirect transmission. Practitioners who know they have an
• People who are coughing and/or sneezing should cover
their nose and mouth whilst coughing/sneezing and use
tissues to catch their cough or sneeze.
6
Infection Control in Optometric Practice
However, particular care needs to be taken with inanimate
objects that enter sterile parts of the body (which is
unlikely in optometric practice) or are in close contact
with mucous membranes as these present particular crossinfection hazards (Wilson 2006 p. 40).
• People should dispose of these tissues into the nearest
receptacle as soon as possible after use (tissues should
be disposed of in normal domestic refuse and do not
require special treatment: Department of Health and
Health Protection Agency 2008).
• Hand
hygiene
should
be
performed
after
coughing/sneezing.
Disinfection
Disinfection reduces the number of microorganisms to a
level at which they are not harmful, although spores are
not usually destroyed. Methods of disinfection include the
use of heat or chemicals and is appropriate for items that
have contact with mucous membranes or which may be
contaminated by microorganisms that are easily
transmitted to others, although sterilisation is preferable
(Wilson 2006 p. 262).
In addition:
• People should avoid touching their mouth, eyes and/or
nose unless hand hygiene has been performed.
Indirect contact via contaminated equipment
This may be from an instrument such as a tonometer, or a
contact lens, including special diagnostic lenses such as
gonioscope lenses.
Sterilisation
Sterilisation is the removal or destruction of all
microorganisms, including spores. This method of
decontamination should be used if the skin is penetrated
or sterile body areas are entered or there is contact with
broken mucous membranes. This is unlikely to occur in
routine community optometric practice.
Contamination may occur because the device was not
decontaminated sufficiently, or because it was later
contaminated from a reservoir of infection such as a
contact lens solution. To reduce the risk of contamination,
bottles of contact lens solutions must be kept with their
lids on when not in use and discarded according to the
manufacturer’s instructions. To facilitate this, it is
recommended that, when a bottle of solution is opened, it
is marked with the date of opening (or the date by which it
must be discarded). If reusable eyedrops or solutions are
used care must also be taken to ensure that no part of the
eye dropper touches the patient, as this may lead to
contamination. Inanimate objects that become
contaminated with pathogenic bacteria and then spread
infection to others are often called fomites.
Following the concern about variant Creutzfeld−Jakob
disease (vCJD), guidance on the decontamination of
contact lenses and other ophthalmic devices was published
by the College of Optometrists and the Association of
British Dispensing Opticians in 1999. This recommends
that, wherever practicable, a contact lens or ophthalmic
device that comes into contact with the ocular surface
should not be used on more than one patient. Where this
is not possible, the advice is to decontaminate the item
using a recognised method. It is anticipated that this
advice will be revised during 2009, so members should
watch the College of Optometrists’ website (www.collegeoptometrists.org) for further information.
There are three levels of decontamination: (1) cleaning;
(2) disinfection; and (3) sterilisation.
Cleaning
Cleaning involves the use of detergent to remove visible
contamination from equipment. This also removes a large
proportion of the microorganisms and is an adequate method
of decontamination for a large range of equipment (Wilson
2006 p. 262). This is because most microorganisms are not
able to survive without moisture, warmth and nutrients and
unless the microorganisms are able to multiply on the fomite
the numbers present are unlikely to be sufficient to transmit
infection in most situations (Rhame 1986, Wilson 2006 p.
40). Providing all equipment is kept clean and dry, the
bacteria will not be able to multiply on the surface and their
presence will be only temporary. Cleaning is usually adequate
for equipment that is in contact with intact skin, such as trial
frames, chin/forehead rests and spectacle frames.
Disposal of Clinical Waste
Clinical waste is defined in the Controlled Waste
Regulations 1992. It means any waste which consists
wholly or partly of:
• human or animal tissue
• blood or bodily fluids
• excretions
• drugs or other pharmaceutical products
• swabs or dressings
• syringes, needles or other sharp instruments
which unless rendered safe may prove hazardous to any
person coming into contact with it. And:
7
S Blakeney
Bellamy K, Alcock R, Babbb JR et al. (1993) A test for the
assessment of ‘hygienic’ hand disinfection using rotavirus.
J Hosp Infect 24, 201−10
• any other waste arising from medical, nursing, dental,
veterinary, pharmaceutical or similar practice,
investigation, treatment, care, teaching or research, or
the collection of blood for transfusion, being waste
which may cause infection to any person coming into
contact with it.
Cartmill TDI, Parigrahil H, Worsley MA et al. (1994)
Management and control of a large outbreak of diarrhoea
due to Clostridium difficile. J Hosp Infect 27, 1−16
Most of the waste that optometrists produce is unlikely to
be an infection hazard. Optometrists should ensure that
they have appropriate disposal arrangements with their
waste disposal contractor. Discussion of the disposal of
waste is outside the scope of this article and optometrists
are referred to the College of Optometrists’ Guidance on
the Disposal of Waste from Optometric Practice (2009b)
for more detailed information.
Casewell MW (1986) Epidemiology and control of the
‘modern’ methicillin resistant Staphylococcus aureus. J
Hosp Infect 7 (suppl. A), 1−11
Centers for Disease Control and Prevention (2002)
Guideline for hand hygiene in health-care settings –
recommendations of the Healthcare Infection Control
Practices
Advisory
Committee
and
the
HICPAC/AHEA/APIC/IDSA Hand Hygiene Task Force.
Morbid Mortal Weekly Rep 51 RR-16 Oct 25 2002; available
online at: http://www.cdc.gov/mmwr/PDF/rr/rr5116.pdf
Summary
All optometrists and practice staff have a responsibility to
themselves, their patients and colleagues to control
infection as much as is practicable. Such procedures need
not be onerous and need to be embedded into practice
protocols. It is recommended that optometrists contact
their local primary care organisation to see what help they
can offer with this.
College of Optometrists and Association of British
Dispensing Opticians (1999) Guidance on the Re-use of
Contact Lenses and Ophthalmic Devices. London:
College of Optometrists and Association of British
Dispensing Opticians
College of Optometrists (2004) Framework for clinical
governance module on risk management. Available online
at: http://www.college-optometrists.org/index.aspx/pcms
/site.publication.Frameworks/displayAmount/5/page/2/
Further information
Further information can be found in the College of
Optometrists’ Guidance on Infection Control (2009a).
College of Optometrists (2009a) Guidance on infection
control. Available online at: www.college-optometrists.org
(in preparation)
Acknowledgement
College of Optometrists (2009b) Advice on the Disposal of
Waste from Optometric Practice. London: College of
Optometrists (in press)
The author would like to thank Karen Hawker, Lead Nurse
Infection Prevention and Control for NHS West Kent, for
her very helpful comments and suggestions on this paper.
Department of Health (2008a) The Health Act 2006: code
of practice for the prevention and control of healthcare
associated infections. Gateway ref. 9286. Available online
at: www.dh.gov.uk
References
Ali Y, Dolan MJ, Fendler EJ et al. (2000) Alcohols. In: Block
SS (ed.) Disinfection, Sterilization and Preservation.
Philadelphia: Lippincott Williams & Wilkins, Chapter 12
Department of Health (2008b) Catch it, bin it, kill it –
respiratory and hand hygiene campaign. Available online at:
www.dh.gov.uk/en/Publicationsandstatistics/Publications
/PublicationsPolicyAndGuidance/DH_080839 (accessed
16/1/09)
Barrett SP, Teare EL, Sage R (1993) Methicillin-resistant
Staphylococcus aureus in three adjacent health districts
of South East England 1986−91. J Hosp Infect 24,
313−25
8
Infection Control in Optometric Practice
Olsen RJ, Lynch P, Coyle MD et al. (1993) Examination
gloves as barriers to hand contamination in clinical
practice. JAMA 270, 350−3
Department of Health and Health Protection Agency
(2008) Pandemic Flu. Guidance for Environmental
Health Practitioners. London: Department of Health and
Health Protection Agency
Pratt RJ, Pellowe CM, Wilson JA et al. (2007) Epic2:
national evidence-based guidelines for preventing
healthcare-associated infections in NHS hospitals in
England. J Hosp Infect 65, S1−61; see p. S22
Fendler EJ, Ali Y, Hammond BS et al. (2002) The impact of
alcohol hand santizer use on infection rates in an extended
care facility. Am J Infect Control 30, 226−33
Rampling A, Wiseman S, Davis L et al. (2001) Evidence
that hospital hygiene is important in the control of
methicillin resistant Staphylococcus aureus. J Hosp Infect
49, 109−16
Gerding DN, Muto CA, Owens RC Jr (2007) Measures to
control and prevent Clostridium difficile infection. Clin
Infect Dis 46 (suppl.), 43−9
Kampf G, Hollingsworth A (2008) Comprehensive
bactericidal activity of an ethanol-based hand gel in 15
seconds. Ann Clin Microbiol Antimicrob 7, 2
Rhame F (1986) The inanimate environment. In: Bennett
JV, Brackman PS (eds) Hospital Infections. Boston: Little
Brown, pp. 299−324
Larson E (1983) Compliance with isolation technique. Am
J Infect Control 11, 221−5
SI 588 (1992) Controlled Waste Regulations. London:
Stationery Office
Lawrence J, May D (2003) Infection Control in the
Community. Edinburgh: Churchill Livingstone, Chapter 9
SI 1185 (2008) General Ophthalmic Services Contracts
Regulations. London: Stationery Office
Marples RR, Towers AG (1979) A laboratory model for the
investigation of contact transfer of microorganisms. J Hyg
82, 237−48
Strausbaugh LJ, Crossley KB, Nurse BA et al. (1996)
Antimicrobial resistance in long-term care facilities. Infect
Control Hosp Epidemiol 17, 129−40
Meengs MR, Giles BK, Chisholm CD et al. (1994) Hand
washing frequency in an emergency department. Ann
Emerg Med 23, 1307−12
Tenorio AR, Badri SM, Sahgal NB et al. (2001)
Effectiveness of gloves in the prevention of hand carriage
of vancomycin resistant Enterococcus species by health
care workers after patient care. Clin Infect Dis 32, 826−9
Mylotte JM (1994) Control of methicillin-resistant
Staphylococcus aureus: the ambivalence persists. Infect
Control Hosp Epidemiol 15, 73−7
Thompson BL, Dwyer DM, Ussery XT et al. (1997)
Handwashing and glove use in a long-term care facility.
Infect Control Hosp Epidemiol 18, 97−103
National Institute for Health and Clinical Excellence
(2003) Prevention of healthcare-associated infections in
primary and community care. Available online at:
http://www.nice.org.uk/guidance/index.jsp?action=downl
oad&o=29119
Wagenvoort JHT, Sluijsmans W, Penders RJR (2000) Better
environmental survival of outbreak vs sporadic MRSA
isolates. J Hosp Infect 45, 231−4
Neely AN, Maley MP (2000) Survival of enterococci and
staphylococci on hospital fabrics and plastics. J Clin
Microbiol 38, 724−6
Widmer AF (2000) Replace hand washing with use of a
waterless alcohol handrub? Clin Infect Dis 31, 136−43
Wilson J (2006) Infection Control in Clinical Practice.
Edinburgh: Baillière Tindall
Newsom SWB (2001) The history of infection control:
Semmelweis and handwashing. Br J Infect Control 2, 24−7
Zimakoff J, Stormark M, Larsen SO (1993) Use of gloves
and handwashing behaviour among health care workers in
intensive care units. A multicentre investigation in four
hospitals in Denmark and Norway. J Hosp Infect 24, 63−7
Noble WC (1975) Dispersal of skin microorganisms. Br J
Dermatol 93, 477−85
9
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Multiple Choice Questions
This paper is reference C-10714. Three credits are available. Please use the inserted answer sheet. Copies can be obtained from
Optometry in Practice Administration, PO Box 6, Skelmersdale, Lancashire WN8 9FW. There is only one correct answer for each
question.
6.
1. Which one of the following statements is true?
(a) NICE recommends that disposable gloves are worn
for all clinical activities where the patient’s skin is
touched
(b) Gloves are a complete protection against hand
contamination
(c) Providing they are washed thoroughly, gloves can be
reused for different patients
(d) Gloves are not required for most situations in
community optometric practice
2.
(a)
(b)
(c)
(d)
(a)
(b)
(c)
(d)
What is the approximate size range of viruses?
10−250nm
10−1000nm
20−250nm
20−1000nm
7. Which one of these statements is true?
(a) A common area that is missed when washing hands is
the palm of the hands
(b) Cotton towels should be used to dry the hands after
hand washing, as they are soft and less likely to cause
irritation
(c) Even when used correctly, alcohol handrubs are less
effective than conventional hand washing with soap
and water
(d) A hand cream should be applied regularly to skin to
protect the hands from the drying effects of hand
decontamination
3. Which one of these statements is false?
(a) Under the NHS in England performers have to ensure
they have appropriate arrangements for infection
control
(b) Employers have a legal duty to ensure that workplace
hazards are identified
(c) The NHS considers the prevention of HCAI as a high
priority
(d) Clostridium difficile can form spores which are
resistant to alcohol handrubs
8.
(a)
(b)
(c)
(d)
4. Which one of these statements is true?
(a) MRSA causes different types of infection to sensitive
strains of S. aureus
(b) Healthy people are unlikely to develop an MRSA
infection
(c) Alcohol rubs are not effective against MRSA
(d) MRSA is commonly spread by airborne transmission
5.
(a)
(b)
(c)
(d)
Which one of these statements relating to the NICE
guidelines on hand hygiene is true?
Hands only need to be decontaminated when
practitioners see patients they know have an
infection
It is only necessary to cover cuts and abrasions if they
are actively leaking fluid
Alcohol handrubs should only be used if hands are
not visibly dirty
When washing the hands, hands must be rubbed
together for 5 seconds
What is the optimum concentration range for the
antimicrobial activity of alcohol solutions?
60−95%
60−100%
50−95%
50−100%
9. Which one of the following statements is false?
(a) Resident flora rarely cause disease
(b) Transient flora are difficult to remove, even with good
hand hygiene
(c) Resident flora are not readily transferred to other
people or surfaces
(d) Transient flora are more easily acquired when the
surface is moist
What does HCAI stand for?
Hands can always be infected
Healthcare autoimmune disease
Healthcare-associated infections
Hands could always infect
10
Infection Control in Optometric Practice
15. How long can C. difficile spores survive on hard
surfaces?
(a) Up to 5 days
(b) Up to 5 hours
(c) Up to 5 weeks
(d) Up to 5 months
10. Which one of the following statements is false?
(a) All trial frames and spectacle frames must be
sterilised between patients
(b) Cleaning involves the use of detergent to remove
visible contamination
(c) Disinfection reduces the number of microorganisms
to a non-harmful level
(d) Sterilisation is the removal or destruction of all
microorganisms, including spores
11. Which one of the following statements is false?
(a) Semmelweis found that the introduction of hand
washing with chlorinated lime solution reduced
infection
(b) Pasteur advocated the germ theory of disease
(c) Semmelweis was a Hungarian physician
(d) Semmelweis demonstrated the efficiency of alcohol
handrubs in reducing disease
12. Approximately how many cases of Acanthamoeba
keratitis are associated with contact lens use?
(a) 55%
(b) 65%
(c) 75%
(d) 85%
13. Which of the following statements regarding bacteria
is false?
(a) Most die rapidly in the absence of water
(b) Most thrive in alkaline conditions
(c) Some can generate energy aerobically or
anaerobically depending on their environment
(d) Some can withstand temperatures as high as 100°C
14. Approximately what percentage of skin flakes have
been shown to carry viable organisms?
(a) 2%
(b) 5%
(c) 10%
(d) 15%
11
S Blakeney
12
Optometry in Practice Vol 10 (2009) 13–18
Legal Cases in Optical Practice: Part One
Rakesh Kapoor
BSc(Hons) MCOptom MBA
Specsavers Opticians, Wembley, Middlesex
Date of acceptance: 3 February 2009
Introduction
The rest of this paper explores legal issues that are relevant
to everyday practice and helps the reader understand the
implications by giving fictitious examples. Please note that
the examples are not real cases and so do not create a
precedent, in the way that case law is derived.
The last few years have seen extensive changes in the
regulation of all healthcare professionals, it is fair to say,
instigated by the awful truth uncovered during the
Shipman inquiry. Health professionals are now more
accountable for their actions and can no longer rely solely
on the phrase ‘professional judgement’. In present times
the public have become less deferential and more
demanding of the professions. The introductory chapter in
the Health and Social Care Act 2008 states:
In this paper it is intended to explore:
1.Common law of trespass, consent and negligence
2.Consent and ‘Gillick competence’
3.Dealing with a patient with learning difficulties
Whilst patients and the public rightly hold the substantial
majority of health professionals in high esteem, the
need for reform to sustain confidence in the regulation
of healthcare professionals has been underlined by the
findings of a number of high-profile inquiries into
doctors who have harmed their patients, most notably
Shipman, Kerr-Haslam, Ayling and Neale inquiries.
Common Law of Trespass, Consent and
Negligence
My eyes have never felt the same since I had that puffer test!
The scenario
Mrs Wallace attended for an eye examination. She had not
visited for some time so was very nervous about the visit.
On arrival the receptionist took her details and then
escorted her to a pretest area. At this point Mrs Wallace
was not told anything about the tests which were being
undertaken.
In November 2008 the optical regulator, the General
Optical Council, after consultation and direction from the
Council for Healthcare Regulatory Excellence, adopted a
change in the standard of proof ‘when facts are disputed’
when a case is presented to the Fitness to Practise (FTP)
committee. The previous criminal standard, ie facts are
proven ‘beyond all reasonable doubt’, has now been
replaced by the less demanding test of the civil standard,
which simply requires the facts to be proven ‘on the
balance of probabilities’.
The assistant who conducted the pretest asked Mrs Wallace
to position her head and get ready for a ‘puff of air’. As
soon as the puff of air was released Mrs Wallace violently
moved away from the tonometer. She thought the machine
must have been faulty and asked if the test was as it should
be. She was told it was normal, but she was so shaken by
the experience that she refused to allow the assistant to
conduct tonometry on her other eye.
When there are disputed issues of facts, the FTP
committee uses the civil standard to test the facts. The
Law Lord, Lord Nicholls of Birkenhead, helps to explain
how to make a judgement using the following example:
The optometrist then took Mrs Wallace into the consulting
room. He invited her to sit and briskly continued with his
routine. At the end he stated to Mrs Wallace, ‘You refused to
have tonometry done so I can’t say if you have glaucoma’. Mrs
Wallace replied: ‘If you mean that test that nearly injured my
eye, I would have never had that done if I had known what was
involved’. ‘Don’t worry, your results are normal; there is
nothing to worry about,’ the optometrist replied.
It would need more cogent evidence to satisfy one that
the creature seen walking in Regent’s Park, if it is seen
outside the zoo on a stretch of greensward regularly
used for walking dogs, then of course it is far more
likely to be a dog than a lion. If it is seen in the zoo
next to the lions’ enclosure when the door is open,
then it may well be more likely to be a lion than a dog.
Address for correspondence: R Kapoor, Specsavers Opticians, 476 High Road, Wembley, Middlesex HA9 7BH, UK.
13
© 2009 The College of Optometrists
R Kapoor
1. The optometrist owed a duty of care to a standard of
‘Clapham omnibus optometrist’. This is a descriptive
formulation of a reasonably educated and intelligent
but non-specialist optometrist − a hypothetical person
against whom a defendant's conduct might be judged.
‘The man on the Clapham omnibus’ was first mentioned
by Greer LJ in Hall v. Brooklands Auto-Racing
Club (1933).
2. There may have been a breach of duty on the basis that
the test was not explained, but otherwise the test
carried out is commonly performed and the
machine was not faulty, so there was no breach of
duty in performing the test.
3. The breach caused permanent harm. Although the
patient claims this, there is no proof that this was the
cause of her symptoms. A report from an expert to prove
harm would be required, stating that the damage is
permanent.
At this point the test ended. Mrs Wallace was worried that
the pretest might have damaged her eye, and left the
practice immediately. She subsequently noticed the eye
that was tested started to feel dry so she wrote a letter of
complaint.
The manager of the practice passed the letter to the
optometrist who dismissed her complaint: ‘We do this test
on everybody over 40. I’ve never known anybody having dry
eye after such a test,’ and so did nothing about it.
The issues
In this case several issues need to be looked at. Firstly, was
consent granted to perform the pretest? This is a commonlaw issue and, if trespass is proven, ie Mrs Wallace did not
give or imply consent, then there is a case to answer.
When such questions are asked case law needs to be
examined. Chatterton v. Gerson (1981) can be used to
test if consent was given. In this case a doctor failed to
disclose the risks associated with a procedure. The judge
ruled: ‘In my judgement once the patient is informed in
broad terms of the nature of the procedure which is
intended, and gives her consent, that consent is real, and
the cause of the action on which to base a claim for failure
to go into risks and implications is negligence, not
trespass’. So, was Mrs Wallace given in broad terms the
nature of the procedure? If so, she would then need to
prove negligence.
On this basis Mrs Wallace's only claim would be for the
distress caused to her which arose as a result of a breach
of the standard of care expected for a practitioner.
Although, if she were successful, any financial award by the
court would be unlikely to be prohibitively high, the
outcome would have a serious impact on the practice's
reputation.
Consent and Gillick Competence
The scenario
It is important to differentiate between trespass and
negligence as the consequences are different. To claim
compensation for trespass the individual making the
complaint does not have to show loss or damage, but
merely that the act of trespass took place. In cases of
negligence, damages are awarded if the patient incurs
damage − which may be physical, mental or financial − as
a direct result of the negligence.
The optometrist calls his next patient into the consulting
room for an eye examination. The patient is 14-year-old
Katie Richards. Because of Katie’s age, the optometrist
asks Katie’s father to join them during the eye
examination. However her father declines and says he
would prefer to wait outside.
The optometrist begins his eye examination and finds
Katie to be an intelligent young woman who asks lots of
questions. Katie is found to be myopic, requiring
spectacles for school and television only. When the
optometrist tells Katie this, she is adamant she does not
want her father to know she requires spectacles. The
optometrist is unsure how to deal with this.
To prove that negligence occurred, the complainant must
establish (prove: see below for the burden of proof) three
things:
1. That a duty of care existed
2. That a breach of this duty occurred
3. That damage occurred as a result of the breach
The issues
Each of these must be proven ‘on balance of probabilities’.
A well-known case law, Bolam v. Friern Hospital
Management Committee, is used since in this case the
judge devised a test to prove negligence.
The patient−practitioner relationship and patient
confidentiality when dealing with children
Patient confidentiality is a human right, but when it comes
to minors, how far does this go? Unless it is established
14
Legal Cases in Optical Practice: Part One
In the consulting room, Mr Patel sits Stephen down and
proceeds with the eye examination. He asks John: ‘Do you
mind if I ask you about Stephen?’ John is unsure how to
react but responds affirmatively. The eye examination
continues and Mr Patel addresses John throughout.
that the child is competent it is usual to take up the
default position to inform parents of findings. However the
famous case of Gillick v. West Norfolk and Wisbech Area
Health Authority established the concept of ‘Gillick
competence’ in relation to the treatment of the wishes of
a child under 16 years old. According to this ruling, a child
who is capable of understanding the nature, purpose and
possible treatment of a disorder can give consent or
withhold consent information to legal guardians of a
diagnosis or treatment. In other words, if the optometrist
feels the patient has understood fully but then refuses to
give consent in passing this information to parents, the
optometrist would have to withhold this information from
parents.
After carrying out an objective examination, Mr Patel
finalises the prescription and hands it to John. At this
point, Stephen stands up and asks to see the manager. He
wishes to complain about his eye examination as he feels
that Mr Patel had not addressed him directly: ‘Just because
I have Down’s syndrome doesn't mean that the optician
shouldn't explain to me what is wrong with my eyes’.
The issues
The College of Optometrists in its professional conduct
ethics and guidance also mentions the patient−practitioner
relationship with minors. It refers to the Gillick v. West
Norfolk and Wisbech Area Health Authority case in making
such judgements.
Mr Patel, the optometrist, assumed from Stephen’s
appearance that he must have a problem with
understanding. On this basis, he proceeded with the eye
examination and gathered whatever information he could
from John. The patient’s comprehension was not assessed
in any way. It was simply assumed that he would not be
capable of understanding. The optometrist used all
objective tests to assess Stephen’s vision and did not
attempt to communicate with him at all.
In this case, the patient has made it clear she does not wish
her family to know about her eye condition. In law, since
the patient is under 16 and therefore a minor, does she
have this right? Katie has not given her optometrist
consent to discuss her case with her parents, but she is
only 14 years old.
The second issue here is of consent. The optometrist
assumed that, because of the patient’s disability, he did not
need to obtain consent to communicate with the third party.
Normally good practice would entail avoiding getting into
situations such as this. It is best always to invite guardians
of minors to sit in on the eye examination. It is also best to
try to understand the child’s viewpoint and then explain
the benefits of guardians knowing the issues, but if the
young patient is still adamant, the optometrist should
keep full records and then make a judgement on whether
the child is ‘Gillick-competent’.
The considerations in this case are:
1. The optometrist’s communication skills
2. Guidance from professional bodies in dealing with
patients with learning difficulties
3. Whether consent was obtained from the patient to
divulge information to the other party and whether this
breaches the Data Protection Act.
Dealing with a Patient with Learning
Difficulties
Communication skills
Like other clinicians, all opticians have a responsibility to
explain to patients the testing process and to inform them
of the results obtained. In this case, the optometrist
assumed from the patient’s appearance that he had
learning difficulties and therefore a problem in
comprehension. Core competency 1.9 relates to:
Just because I’m disabled does not mean I don’t
understand what is wrong with my vision!
The scenario
Stephen, a 29-year-old man with Down’s syndrome, attends
for an eye examination. Mr Patel, the optometrist, calls
Stephen in and notices his disability. He invites Stephen’s
companion, John, into the consulting room with him. John
is a friend of Stephen’s mother and has given Stephen a lift
to the practice.
The ability to communicate with patients who have
poor, or non-verbal communication skills, or those who
are confused, reticent or who might mislead.
15
R Kapoor
Consent and data protection
Good practice requires all tests and findings to be
explained to patients, and a clear management plan
discussed and agreed with them. If this is not possible,
then the records need to be annotated to explain how this
was attempted.
The fact that Stephen's healthcare information was
discussed with John makes the Data Protection Act
relevant to this case. Reports or clinical findings provided
to third parties (John in this case), and the discussion of a
patient’s health details with them, constitutes the
processing of sensitive data under the Data Protection Act
1998. Under this Act, the optometrist must obtain explicit
consent.
Guidance
The College of Optometrists' guidance on examining
patients with learning difficulties recommends few
measures but relies on the optometrist’s judgement of
what may be required. The guidance can be summarised
as follows:
After a government review of sensitive information a
National Health Service (NHS) group was set up that is
responsible for making sure that such information is dealt
with appropriately. This group is called the 'Caldicott
guardians' and every local area will have an appointed NHS
Caldicott guardian.
• It may be necessary for patients to visit the practice
before the day of the test to familiarise them with the
surroundings.
• Effective communicating and listening with the patient
and the carer can establish the requirements for
conducting the examination.
• Whenever appropriate, only seek a briefing from carers
after obtaining explicit consent.
• When necessary, adapt techniques and use alternative
methods for assessing the patient and allow ample time.
• Cycloplegic examination and dilation may be necessary
to obtain accurate results.
• The extent of examination and accuracy of results may
be limited so full records should be kept.
The Caldicott guardians have advised that ‘consent should
be absolutely clear and requires a positive action’. It is
recommended that an optometrist must be satisfied as to
whether patients will be able to understand the process of
an examination and whether they will be able to provide
the necessary consent. If the patient cannot consent, the
optometrist may, with the permission of the carer, divulge
information. Ideally, you should document details of your
reasons for believing the patient to be unable to
understand a procedure and/or give consent.
The Mental Capacity Act 2005 applies to patients who are
certified as having some form of mental incapacity. It
states that all healthcare practitioners should use five
statutory principles in assessing people with mental
incapacity. These are paraphrased as follows:
1. You must assume patients have full mental capacity
unless it is established that they do not.
2. You must not treat individuals as if they are unable
to make a decision unless you have taken all
practicable steps to help them to do so, and this has
been unsuccessful.
3. You must not treat people as if they are unable to
make a decision merely because they have made an
unwise decision.
4. If you act or make a decision for a person because of the
provisions of this Act, your action or decision must be
made in the person's best interests.
5. If you act or make a decision for a person because of the
provisions of this Act, you must consider beforehand
whether you can achieve the objective in a way that is
less restrictive of the person’s rights and freedom
of action.
16
Legal Cases in Optical Practice: Part One
References
Bolam v. Friern Hospital Management Committee [1957]
1 WLR 583
Chatterton v. Gerson [1981] 1 ALL ER 257
College of Optometrists (2008) Section 26: Examining
Children and Vulnerable Adults guideline. In: College of
Optometrists Members' Handbook. London: College of
Optometrists
College of Optometrists (2008) Scheme for Registration
Trainee Handbook. Annex C. London: College of
Optometrists
College of Optometrists (2008) Code of Ethics and
Guidelines for Professional Conduct. London: College of
Optometrists
Gillick v. West Norfolk & Wisbech HA (1986) AC112
Hall v. Brooklands Auto-Racing Club (1933) 1 KB 205
Lord Nicholls of Birkenhead re H (minors) (Sexual Abuse:
Standard of Proof) (1996) AC 563, 586
17
R Kapoor
Multiple Choice Questions
This paper is reference C-10720. One credit is available. Please use the inserted answer sheet. Copies can be obtained from
Optometry in Practice Administration, PO Box 6, Skelmersdale, Lancashire WN8 9FW. There is only one correct answer for each
question.
1.
(a)
(b)
(c)
(d)
2.
(d)
Regarding negligence claims, which of the following
statements is false?
A duty of care must be established by the claimant
Any breach of duty must have caused harm
It must be established that the harm would not have
occurred ‘but for’ the optician’s act or omission
The burden of proof is ‘beyond reasonable doubt’
3.
(a)
(b)
(c)
(d)
A ‘Gillick-competent’ child:
Is nearly 16 years
Asks lots of questions
Understands issues of treatment and management
Will have no legal guardian
(a)
(b)
(c)
(c) An act done, or decision made, under this Act for or
on behalf of a person who lacks capacity must be
done, or made, in that person’s best interests
(d) Individuals can be regarded as unable to make a
decision if they tend to make unwise ones
If an optometrist provides an overview of what a
procedure involves but fails to discuss risks and
implications fully, what cause of action could a
patient bring?
Trespass
Negligence
Breach of contract
Criminal assault
6.
(a)
(b)
(c)
In legal terms what is a ‘Clapham omnibus’ optician?
A layperson
A pre-registration optician
A hypothetical optician of reasonable competence
with no specialised training
(d) An optician with specialised training
4. What best defines explicit consent?
(a) Consent which can be presumed from a patient’s
failure to object to a procedure
(b) Consent for medical information to be passed to a
third party
(c) Absolutely clear consent requiring a positive action
by the patient
(d) Consent obtained from a parent or guardian to treat
a ‘Gillick-competent’ child
5.
Which of the following principles should not be used
by healthcare practitioners when treating patients
under the Mental Capacity Act 2005?
(a) Individuals are assumed to have capacity unless it is
established that they lack capacity
(b) Individuals are not to be treated as unable to make a
decision unless all practicable steps to help them do
so have been without success
18
Optometry in Practice Vol 10 (2009) 19–26
Migraine
Andrew Larner
BMBCh MRCP
Walton Centre for Neurology and Neurosurgery, Liverpool
Date of acceptance 9 January 2009
Introduction
Migraine with aura
Headache is a common and distressing condition which
has been a feature of the human condition throughout
history (Rose 1995). Headache is recognised to be a major
cause of impaired quality of life, yet the fact that many
notable individuals (Jones 1999; Box 1) have suffered from
headache indicates that it does not preclude great works
or achievements.
Visual disturbance is the most common form of migraine aura,
although somatosensory (tingling, paraesthesiae, numbness)
and motor (aphasia, weakness) auras may sometimes occur.
The visual aura of migraine is variable between patients,
and may consist of positive or negative phenomena. The
former include spots of light (photopsia), flashing lights
(scintillations), zig-zag shapes sometimes likened to
fortifications (teichopsia) and kaleidoscopic effects with
variable colours. These visual appearances often move
gradually from the periphery of the visual field towards the
centre over a period of 20−30 minutes, sometimes up to an
hour. Dedicated self-observers have sometimes mapped these
changes in great detail (e.g. Aird 1870; Figure 1). Negative
visual phenomena include homonymous visual field loss or
patchy scotomata, and more diffuse complaints such as
blurring, heat haze and ‘water on glass’. Tunnel vision and
even blindness may occur. Other less common visual
phenomena include distortion of the appearance of objects,
such that they appear either too large or too small
(metamorphopsia). There may also be altered perception of body
image, micro- or macrosomatognosia, also known as the ‘Alice in
Wonderland syndrome’ (Larner 2005b, Lippman 1952).
Correct diagnosis and treatment of headache is now the
focus of a worldwide campaign (Steiner 2004). Hence, all
practitioners of medicine and of professions allied to
medicine need to be aware of headache. Amongst the
latter, optometrists are particularly relevant, since so many
individuals with headache will consult an optometrist,
often before any other health professional, in the belief
that their symptoms may represent a primary ocular
problem (Larner 2005a). Various eye disorders are
recognised to be possible causes of headache, including
acute glaucoma, inflammatory ocular disorders and
refractive errors (International Headache Society
Classification Subcommittee 2004).
Although many different headache types may be delineated
based on their clinical features (International Headache
Society Classification Subcommittee 2004), the category
of migraine is probably the most important of these. This
article summarises the clinical features of migraine and
some of its variants, with emphasis on visual phenomena,
and briefly discusses pathophysiology, differential
diagnosis and management.
Jane Austen
Hildegard of Bingen
Charlotte Brontë
Sigmund Freud
Caleb Hillier Parry
Clinical Features
Thomas Jefferson
Immanuel Kant
Migraine is an intermittent, episodic disorder, broadly
classified into migraine with aura, formerly known as
classical migraine, and migraine without aura, formerly
known as common migraine. Because migraine with aura
may have very prominent visual phenomena, it may be the
form more commonly seen by optometrists.
Charles Lutwidge Dodgson (Lewis Carroll)
Friedrich Nietzsche
Box 1. Some famous (possible) migraineurs
Address for correspondence: Dr AJ Larner, Walton Centre for Neurology and Neurosurgery, Lower Lane, Fazakerley, Liverpool L9 7LJ.
19
© 2009 The College of Optometrists
A Larner
Pathophysiology of Visual Phenomena
in Migraine
Visual auras have been variously interpreted over the years.
In the 12th century Hildegard, the Abbess of Bingen in
Germany, thought they were divine visions or revelations;
centuries later the illustrations she drew were recognised
as typical of migraine auras (Singer 1928).
Cortical spreading depression (CSD), first discovered
experimentally by Leão (1944), is an intense
depolarisation of neuronal and glial membranes with loss
of their resistance and a cessation of synaptic activity,
which is thought to underlie migraine aura. There are a
number of avenues of evidence to support this idea. The
clinical observation of the progression of aura suggests a
velocity of spread across the cortex (3mm/min) which is
similar to that of experimentally observed CSD.
Investigative modalities such as functional magnetic
resonance imaging (MRI) and magnetoencephalography
provide evidence that CSD underlies aura. Medications which
prevent migraine, including propranolol, topiramate,
amitriptyline and sodium valproate, have been shown to block
CSD. Brain ischaemia has sometimes been suggested as the
cause of aura, but the evidence is less compelling than for
CSD, although ischaemia may trigger CSD.
Figure 1. Airy’s (1870) observations of his own visual migraine
auras
Generally, as the visual symptoms abate, the headache
phase of migraine builds in intensity, its character typically
described as a throbbing or pulsating sensation, often
more or less lateralised, often with associated systemic
features such as nausea and dizziness. Another visual
phenomenon may now become apparent, namely
photophobia, requiring the patient to turn off lights, close
the curtains or wear dark glasses. Other normal sensory
phenomena may also be unpleasant, including sounds
(phonophobia) and smells (osmophobia). Patients prefer
to be still, since even minor exercise such as climbing
stairs or even head shaking may exacerbate symptoms.
The photophobia which characterises migraine headaches
is thought to reflect a lack of habituation to sensory
stimuli, a sensory processing disturbance with changes in
cortical synchronisation.
Headache may improve or abort after vomiting or sleep, or
persist in an attenuated form for up to 72 hours, leaving
the individual feeling drained and listless and often unable to
work (absenteeism) or working ineffectively (presenteeism).
Migraine Variants of Particular Relevance
to Optometrists
Patients will seldom be seen by practitioners during an
aura, or even during the headache phase. Hence by the
time patients are examined there are generally no
ophthalmic findings. If signs such as visual field defects,
papilloedema or cranial nerve palsies are present, other
diagnostic possibilities need to be considered (see below).
As indicated by the distinction between migraine with or
without aura, migraine is a pleomorphic condition. Since
visual phenomena are prominent in some of these other
migraine variants it behoves optometrists to be aware of
them. These are variants, as distinct from subtypes, since
their pathophysiology is believed to be similar, with the
possible exception of ophthalmoplegic migraine.
In the adult population, migraine is two to three times
more common in women than men, suggesting that
hormonal factors may contribute to pathogenesis.
Menarche, pregnancy and menopause may all influence
headache frequency and severity. Migraine with aura
usually presents before the age of 40 years. De novo
diagnosis above this age may require investigation to
exclude other causes of headache and/or visual
disturbance, including transient ischaemic attacks (TIAs),
cerebral neoplasm, temporal arteritis, epilepsy and pituitary
macroadenoma (Evans & Bruining 2002), although very-lateonset migraine with aura is described (Larner 2007).
Aura without headache
Visual aura may occur in isolation, without a succeeding
headache. This has been termed migraine without
headache or migraine equivalent, but is now classified as
‘typical aura without headache’ (International Headache
Society Classification Subcommittee 2004). The differential
diagnosis encompasses cervical arterial (carotid or vertebral)
dissection and, particularly in older individuals, ocular TIAs.
20
Migraine
Basilar-type migraine
(International
Headache
Society
Classification
Subcommittee 2004), in part because of changing
perceptions about its pathophysiology. In such cases MRI
may show focal swelling of the oculomotor nerve (observed
pathologically in the 19th century), with enhancement in
the acute phase, suggesting that this may be a focal
demyelinating neuropathy; response to steroids would also be
consistent with this interpretation (Doran & Larner 2004).
Although dizziness is not an uncommon symptom of
migraine attacks, florid neurological symptoms and signs
suggestive of posterior fossa involvement, such as true
vertigo, tinnitus, deafness, ataxia, dysarthria and even
transient loss of consciousness, may sometimes occur
(Bickerstaff 1961). There may be accompanying visual
phenomena including diplopia and bilateral visual
disturbance which may involve both temporal and nasal
fields. This condition was previously known as ‘basilar
artery migraine’ or ‘basilar migraine’, in the belief that the
basilar artery was implicated in pathogenesis, but evidence
for this is lacking and hence the terminology has changed
to ‘basilar-type’.
Differential Diagnosis of Migraine
The diagnosis of migraine with or without aura is entirely
clinical, based on a focused history taking. Diagnosis is
often therefore very straightforward. Consultation with a
neurologist and brain imaging are generally not required.
However, there are a number of conditions which may
enter the differential diagnosis of migraine which do
require a different input and treatment. Broadly these may
be divided into other headache disorders and other
neurological conditions. Examination findings such as
persistent visual field defect, papilloedema or cranial nerve
palsy should also be red flags for a diagnosis other than
migraine.
Retinal migraine
The characteristic feature of this rare condition is
monocular visual phenomena, such as aura, altitudinal
field defect, scotomata or even blindness, followed by or
concurrent with migraine headache. Care must be
exercised in accepting a history of monocular visual
phenomena at face value, since patients may have difficulty
in distinguishing unilateral and bilateral symptoms. As
with typical aura without headache, there are important
differential diagnoses for these visual phenomena,
including ocular TIA, structural disorders of the eye such
as retinal detachment and optic neuropathy.
Other Headache Disorders
Tension-type headache
Migrainous infarction, migrainous stroke
Classically, neurology texts have distinguished between
migraine and tension-type headache, the latter being
characterised by ‘featureless’ headaches, present for hours
or days, likened to a band around the head or a pressure on
top of the head, and usually responding to simple
analgesia. Some patients refer to them as ‘normal
headaches’. However, concurrence of migraine and
tension-type headaches is not infrequent, and it may be
necessary to ask patients how many headache types they
think they have.
One of the definitions of migrainous stroke is an aura
lasting more than 7 days. Generally migrainous stroke is
rare (smoking and oral contraceptive pill use add to the
risk), and other causes of stroke should be vigorously
sought before accepting this as a diagnosis of exclusion.
Ophthalmoplegic migraine
Diplopia with an external ophthalmoplegia, typically an
oculomotor (third) or abducens (sixth) nerve palsy
accompanied by migraine-type headache, has been termed
ophthalmoplegic migraine. However, the headache is
atypical since it may last a week or more. Clearly, a
structural lesion, such as a posterior communicating
artery aneurysm causing an oculomotor nerve palsy, needs
to be excluded with this presentation. Cases of
ophthalmoplegic migraine are in fact extremely rare: a
French retrospective epidemiological study identified only
9 possible cases in more than 52000 headache
presentations (Giraud et al. 2007). Moreover, this disorder
has now been reclassified as a cranial neuralgia
Medication overuse headache
Chronic daily headache (more than 15 headache days per
month) should always prompt questions about analgesic
use, since regular use of most analgesics will lead to
medication overuse headache, also sometimes called
medication-maintained headache. The importance of
identifying this condition cannot be overemphasised since
all therapeutic approaches other than withdrawal of
medication are destined for failure as long as regular
analgesic use continues to drive the headache disorder.
21
A Larner
Cluster headache
migraine but symptoms are usually transient rather than
recurrent. Concurrent neck pain may be a clue to the
diagnosis, but this is not invariably present.
Cluster headache, formerly and confusingly known as
‘migrainous
neuralgia’,
should
be
relatively
straightforward to differentiate from migraine on the basis
of the clinical history. Here the pain is strictly unilateral,
attacks are generally briefer (up to 3 hours), the pain is so
intense that patients prefer to move about in seeking
relief, and there are autonomic phenomena such as red eye
(chemosis), partial ptosis and miosis, eye watering
(epiphora) and ipsilateral nasal blockage or watering.
Attacks occur on a daily basis, often at a similar time each
night, sometimes for weeks on end before the cluster bout
resolves, only to recur again, sometimes at a similar time
of year. Because of the autonomic phenomena, cluster
headache is now classified with the trigeminal autonomic
cephalalgias. Other members of this group, paroxysmal
hemicrania and short-lasting unilateral neuralgiform
headache with conjunctival injection and tearing
(SUNCT), are much less common than cluster headache
and are characterised by briefer but more frequent
unilateral attacks of pain (Larner 2008).
Pituitary tumour
It is well recognised that pituitary tumours may be
complicated by episodic migraine, as well as other
headache types (Levy et al. 2005), with improvement in
some cases following hypophysectomy. In the absence of
systemic features suggestive of pituitary disease,
examination for bitemporal field defects may be the most
reliable way to exclude local effects of pituitary gland
enlargement.
Multisystem neurological disorders
A number of rare neurological disorders may have migraine
as one of their clinical features, including cerebral
autosomal-dominant arteriopathy with subcortical infarcts
and leukoencephalopathy (CADASIL), mitochondrial
cytopathies, channelopathies such as familial hemiplegic
migraine and hereditary haemorrhagic telangiectasia in
association with cerebral arteriovenous malformations.
Although much beloved by neurologists, all these
conditions are extremely rare and hence unlikely to be
encountered in optometry practice. It may be added that
the old belief that strictly lateralised migraine headaches
were associated with underlying arteriovenous
malformations seems to be without foundation.
Chronic migraine, transformed migraine
Some patients with typical migraine with or without aura
may experience a change in symptomatology over the
years, such that the acute attacks tend to become less
severe and a more chronic headache disorder evolves. This
has been variously termed as chronic migraine or
transformed migraine. Headache may occur daily or almost
daily, which necessitates exclusion of medication overuse
headache before applying this diagnostic label.
Treatment of Migraine
Although treatment of migraine may be deemed to lie
outwith the remit of optometry practice, nonetheless
some awareness of management is appropriate if only to
avoid misleading advice, such as the need to see a
neurologist (urgently or otherwise), have a brain scan or
even to attend hospital immediately. Referral to the
general practitioner and/or self-directed treatment will
suffice in the majority of cases once a definite diagnosis of
migraine has been made.
Other Neurological Conditions
Ocular TIA
Transient interruption of the blood supply to one eye,
typically due to emboli of carotid artery or cardiac origin,
causes monocular blindness which is of sudden onset, with
the defect being maximal from onset, rather than building
up over time. There is no evolution of symptoms, contrary
to that which typifies migraine with aura. Headache is
generally not a feature of ocular TIAs, and if headache does
occur it is of moderate intensity with no specific features.
There are a number of recognised triggers or precipitants
for migraine, avoidance of which may prevent further
attacks. These include sleep deprivation, relaxation after
periods of intense mental activity (‘come down’ or ‘let
down’, often presenting with weekend migraine; one
patient of mine wondered if this pattern of headache
reflected a psychiatric disorder), exercise (‘footballer’s
migraine’), menstruation and dietary factors (chocolate
and cheese seem to be the most reliably identified
Arterial dissection
Spontaneous, atraumatic dissection of the carotid
(Silverman & Wityk 1998) or vertebral (Young &
Humphrey 1995) artery has been reported to mimic
22
Migraine
culprits). Keeping a headache diary and analysing factors
such as these may prove helpful in some instances, perhaps
particularly in the case of migraine related to
menstruation (MacGregor & Hackshaw 2004).
British Association for the Study of Headache (BASH):
www.bash.org.uk
International Headache Society (IHS):
www.i-h-s.org
Drug treatment, if required, may be broadly divided into
two categories: acute and prophylactic. Evidence-based
guidelines for the drug treatment of migraine have been
developed, for example by the European Federation of
Neurological Societies (Evers et al. 2006) and the British
Association for the Study of Headache (2007). Further
information may also be found on appropriate websites
(Box 2). Acute treatments include aspirin, triptans and
non-steroidal anti-inflammatory drugs. It should be noted
that these treatments, including triptans, are of no use for
the treatment of the visual aura per se, and they should
only be taken with the onset of headache. Prophylactic
agents include beta-blockers, antiepileptic drugs
(topiramate, sodium valproate) and amitriptyline.
Mayo Clinic:
www.mayoclinic.com/health/migraine-headache/DS00120
Migraine Action Association (MAA):
www.migraine.org.uk
Migraine in Primary Care Advisors (MIPCA):
www.mipca.org
Migraine Trust:
www.migrainetrust.org
Box 2. Useful websites for further information about migraine
Addressing risk factors for possible migraine
comorbidities, such as stroke and coronary artery disease,
should also be undertaken, cessation of smoking probably
being the most important advice (Diener et al. 2008).
Patent foramen ovale (PFO) of the heart is certainly more
common in patients with migraine with aura as compared
to unaffected individuals and to patients with migraine
without aura, and anecdotal reports have suggested that
PFO closure may improve migraine. However, in the only
double-blind study undertaken to date (Dowson et al.
2008), no significant effect was found for the chosen
primary endpoint (cessation of migraine headache
91−180 days after the procedure).
References
Aird H (1870) On a distinct form of transient hemiopsia.
Phil Trans R Soc Lond 160, 247−64
Bickerstaff ER (1961) Basilar artery migraine. Lancet 1,
15−17
British Association for the Study of Headache (2007)
Guidelines for all Healthcare Professionals in the Diagnosis
and Management of Migraine, Tension-type, Cluster and
Medication-overuse Headache. London: British Association
for the Study of Headache
Conclusion
Diener HC, Küper M, Kurth T (2008) Migraine-associated
risks and comorbidity. J Neurol 255, 1290−301
How should optometrists approach patients with a
complaint of headache? If headaches are intermittent and
attended with visual features, positive or negative, the
suspicion of possible migraine should be raised, the more
so if examination of the eye is normal. Depending on the
frequency of attacks, referral to the general practitioner
may be appropriate, since the majority of such cases can be
managed in the primary care setting.
Doran M, Larner AJ (2004) MRI findings in
ophthalmoplegic migraine: nosological implications.
J Neurol 251, 100−1
Dowson A, Mullen MJ, Peatfield R et al. (2008) Migraine
Intervention with STARFlex Technology (MIST) trial: a
prospective, multicenter, double-blind, sham-controlled
trial to evaluate the effectiveness of patent foramen ovale
closure with STARFlex septal repair implant to resolve
refractory migraine headache. Circulation 117, 1397−404
Evans RW, Bruining K (2002) New onset migraine in the
elderly. Headache 42, 946−7
23
A Larner
Evers S, Afra J, Frese A et al. (2006) EFNS guideline on the
drug treatment of migraine – report of an EFNS task force.
Eur J Neurol 13, 560−72
Silverman IE, Wityk RJ (1998) Transient migraine-like
symptoms with internal carotid artery dissection. Clin
Neurol Neurosurg 100, 116−20
Giraud P, Valade D, Lanteri-Minet M et al. (2007) Is
migraine with cranial nerve palsy an ophthalmoplegic
migraine? J Headache Pain 8, 119−22
Singer C (1928) From Magic to Science. Essays on the
Scientific Twilight. London: Ernest Benn
Steiner TJ (2004) Lifting the burden: the global campaign
against headache. Lancet Neurol 3, 204−5
International
Headache
Society
Classification
Subcommittee (2004) The international classification of
headache disorders, second edition. Cephalalgia 24,
1−160
Young G, Humphrey P (1995) Vertebral artery dissection
mimicking migraine. J Neurol Neurosurg Psychiatry 59,
340−1
Jones JM (1999) Great pains: famous people with
headaches. Cephalalgia 19, 627−30
Larner AJ (2005a) What role do optometrists currently
play in the management of headache? A hospital-based
perspective. Optom Pract 6, 173−4
Larner AJ (2005b) The neurology of ‘Alice’. Adv Clin
Neurosci Rehabil 4, 35−6
Larner AJ (2007) Late onset migraine with aura: how old
is too old? J Headache Pain 8, 251−2
Larner AJ (2008) Trigeminal autonomic cephalalgias:
frequency in a general neurology clinic setting. J Headache
Pain 9, 325−6
Leão AAP (1944) Spreading depression of activity in
cerebral cortex. J Neurophysiol 7, 359−90
Levy MJ, Matharu MS, Meeran K et al. (2005) The clinical
characteristics of headache in patients with pituitary
tumours. Brain 128, 1921−30
Lippman CW (1952) Certain hallucinations peculiar to
migraine. J Nerv Ment Dis 116, 346−51
MacGregor EA, Hackshaw A (2004) Prevalence of migraine
on each day of the natural menstrual cycle. Neurology 63,
351−3
Rose FC (1995) The history of migraine from
Mesopotamian to Medieval times. Cephalalgia 15
(suppl. 15), 1−3
24
Migraine
Multiple Choice Questions
This paper is reference C-10712. One credit is available. Please use the inserted answer sheet. Copies can be obtained from
Optometry in Practice Administration, PO Box 6, Skelmersdale, Lancashire WN8 9FW. There is only one correct answer for each
question.
1.
(a)
(b)
(c)
(d)
2.
(a)
(b)
(c)
(d)
3.
In a typical migraine aura, which of the following
symptoms would be considered a negative
phenomenon?
Scintillations
Photopsia
Teichopsia
Homonymous visual defect
(a)
(b)
(c)
(d)
Which of these clinical features would not support
the diagnosis of migraine headache?
Pulsing sensation
Absence of lateralisation
Exacerbation by mild physical activity
Associated systemic features, eg nausea and dizziness
4.
(a)
(b)
(c)
(d)
Which of these statements about migraine is true?
It is more common in men
It may be complicated by stroke
It is invariably preceded by an aura
It invariably improves after the menopause
5.
Which of the following medications may be used for
the prophylactic treatment of migraine?
Sumatriptan
Paracetamol
Sodium valproate
Ibuprofen
(a)
(b)
(c)
(d)
6. Which of these statements about migraine is true?
(a) Most migraines are secondary/symptomatic
headaches rather than primary/idiopathic headaches
(b) Most patients with migraine require referral for a
specialist neurological opinion
(c) Most migraine patients require a brain scan
(d) Most migraines can be adequately managed in the
primary care setting
In the International Headache Society (2004)
classification, which of the following eye disorders is
not recognised to be a possible cause of headache?
Acute glaucoma
Refractive errors
Ocular inflammatory disorder
Optic neuritis
25
A Larner
26
Optometry in Practice Vol 10 (2009) 27–32
The Alleviation of SEALs
Nigel Best
BSc(Hons) MCOptom
Specsavers Opticians, Darlington, County Durham
Date of acceptance 19 December 2008
Background
producing silicone hydrogels with more base curve options
and lower moduli to try to reduce these mechanical noninflammatory complications.
For many of our contact lens patients continuous wear (up
to 30 nights without removal) is the most desirable
modality. It was in 1981 that the US Food and Drug
Administration approved hydrogel lenses for this purpose.
In the 1980s there was an increased understanding of the
relationship between hypoxia and corneal oedema and in
1984 Holden and Mertz defined the levels of oxygen
needed to avoid overnight swelling with both daily and
continuous-wear lenses. A further study into lens
transmissibility requirements in 1999 by Harvitt and
Bonanno raised the bar even higher for contact lens
manufacturers. Hydrogel lenses were incapable of meeting
these requirements and as such were associated with an
increased risk of complications (Graham et al. 1986,
Mordino et al. 1986, Weissmann et al. 1984).
Case Record
First visit: 08/04/2008
Patient BW, a 43-year-old architect, presented for an eye
examination and contact lens check. He had worn a soft
contact lens in his right eye only for over 10 years, on a 30day continuous-wear basis for roughly the last 6 years. He
was generally satisfied with both the vision and comfort
with his current lens, reporting only occasional episodes of
mild discomfort, and he seldom wore his spectacles. He
was in good health, taking no medication and suffering
from no allergies. He had never attended the Hospital Eye
Service for any treatment and there was no family history
of eye disease. His working day is split fairly equally
between computer work and client visits; his free time is
mostly spent with his young family.
A landmark study (Poggio & Abelson 1993) showed
extended-wear hydrogel patients to have an increased risk
of microbial keratitis compared to daily wear and reduced
confidence in the modality. Further studies have
subsequently confirmed the increased risk (Cheng et al.
1999). In 1999 the arrival of silicone hydrogel lenses
provided practitioners with lenses which provided sufficient
oxygen to prevent corneal oedema following overnight wear
(Sweeney et al. 2004). This increased transmissibility was
achieved by incorporating silicone into the lenses and then
either surface-treating the lenses (Jones et al. 2006, Tighe
2004) or incorporating a wetting agent (Steffen & Schnider
2004) to increase wettability and decrease lipid
interaction. As a result of the silicone incorporated into
these first-generation lenses their modulus was two to three
times higher than that of conventional hydrogel lenses.
This makes the lenses easier to handle for patients with
poor handling capabilities but they are less able to conform
to the shape of the eye, so loose-fitting lenses are less
comfortable (Dumbleton et al. 2002a, 2002b). These lenses
were also associated with mechanical complications such as
giant papillary conjunctivitis and superior epithelial
arcuate lesions (SEALS) (Dumbleton 2003, Holden et al.
2001). The lens manufacturers have responded by
The contact lens check was carried out first because BW
presented wearing his lens. On further questioning he
admitted to very occasionally removing his lens to clean it
with saline from an aerosol if he was experiencing any
discomfort or blurred vision. His current lens was about
2 weeks old.
He provided a copy of his most recent eye examination,
dated 13/03/2007. The details were as follows:
RE: –1.50/–0.25 × 180
LE: plano/–0.25 × 180
He had brought his most recent packaging to the
appointment: his specification was as follows:
RE: Air Optix Night & Day 8.40:13.80/–1.75
LE: no lens
His visual acuity (VA) and overrefraction were:
RE VA 6/5 N5 with good range O/R plano
LE unaided vision 6/5 N5 with good range
Address for correspondence: Mr Nigel Best, 6 The Oval, Wynyard, Cleveland TS22 5SQ.
27
© 2009 The College of Optometrists
N Best
Slit-lamp examination
The lens showed 0.5mm movement on blinking and
recentred briskly following digital displacement. The
centration of the lens was excellent, both in the primary
position and on versional movements. The quality of the
lens surface was good with minimal deposition; no drying
of the lens surface between blinking was apparent.
graded as less than 1 on the Efron scale while the cornea
was healthy. No fluorescein was inserted.
The patient was shown the photograph and the likely
aetiology discussed. It was suggested that switching to a
softer lens material might alleviate the problem. The
higher incidence of corneal inflammatory events with
continuous wear and the risk of microbial keratitis were
also discussed. The patient was happy to continue and was
supplied with the following lens to insert into his right eye
(following irrigation of any remaining fluoroscein with
saline solution):
RE: Coopervision Biofinity 8.60:14.00/–1.75
Following lens removal his non-invasive break-up time was
recorded as 17 seconds in his right eye and his K-readings
were as follows:
7.90 along 180
7.85 along 90
The lens fit was excellent. It centred well in all positions of
gaze, recentred well following displacement and moved
about 0.3mm on blinking. The patient felt the lens was
slightly more comfortable than his previous lenses,
acknowledging that it felt significantly ‘softer’. His VA with
the new lens was 6/5 with no significant overrefraction and
his reading range was adequate. BW was asked to return in
24 hours for an initial check and advised to remove the
lens if he experienced any discomfort, redness or reduced
vision. A 3-month supply of lenses was provided. His eye
examination followed.
Bulbar redness was graded as equivalent to Efron scale 1.3;
limbal redness was 1.5 increasing to 2.2 superiorly. There
was some superficial punctate staining inferiorly equivalent
to Efron 1.9 but of greater concern was a coalescent
arcuate band of staining superiorly. It extended from the 12
o’clock to the 2 o’clock position with only superficial
staining between 11 and 12 o’clock. It had a length of 2mm
and a width of about 0.5mm. The adjacent limbal
vasculature was injected and conjunctival staining was
equivalent to Efron 2.4. A photograph was taken (Figure 1).
Following lid eversion there was only a mild papillary
reaction which was graded as equivalent to Efron 1.2.
His prescription and acuities were as follows:
RE: –1.50/–0.25 × 30 VA 6/5 N5 with good range
LE: plano/–0.50 × 45 VA 6/5 N5 with good range
Fundoscopy was unremarkable.
His intraocular pressures were RE 15mmHg, LE 13mmHg
at 10.30.
One-day check: 09/04/2008
BW returned the following morning for his 1-day check.
His overrefraction and acuities were as follows:
RE: VA 6/5 N5 with good range O/R plano
The fit was as described previously and the lens was
comfortable. The patient was asked to return for a checkup in 1 month’s time.
Figure 1. Superior cornea following continuous wear of Lotrafilcon A
lens.
One-month visit: 16/05/2008
Break-up time following fluoroscein instillation was 12
seconds and the tear meniscus was regular with a height of
0.4mm centrally. No lid parallel conjunctival folds were
present.
Slit-lamp examination
VA and lens fit remained unchanged. The current lens was
1 week old and no significant surface deposition was
observed. BW felt that the new lens was more comfortable
than his previous one.
The slit-lamp examination of the left eye was completely
unremarkable with limbal and bulbar conjunctival redness
Diffuse illumination with white light showed no clinically
significant change in either bulbar or limbal conjunctival
28
The Alleviation of SEALs
BW was reassured that his corneas looked healthier in his
new lens than before and advised to continue lens wear as
before. He was asked to return for a routine check in 6
months’ time and advised on what action to take in the
meantime if his eyes became inflamed or his vision or
comfort reduced.
hyperaemia, graded as 1.3 and 1.5 respectively as before,
although the limbal conjunctiva hyperaemia under the
upper eyelid had now reduced from 2.2 to 1.5. Following
instillation of fluoroscein the superior cornea was now free
of staining, although mild inferior punctate staining was
still apparent, graded as Efron 1.9. The conjunctival
staining under the upper lid had also resolved. A
photograph was taken to demonstrate to the patient the
improvement (Figure 2).
Discussion
SEALs are not commonly seen in hydrogel lens wearers;
however the increasing trend amongst practitioners to fit
silicone hydrogel lenses for both daily and continuous wear
(Efron & Morgan 2008a, 2008b) has led to increasing
reports of SEALs (Dumbleton 2002, 2003, Holden et al.
2001, O’Hare et al. 2001, Stapleton et al. 2006). With
continuous wear of the first-generation silicone hydrogel
lenses, one study found that up to 4.5% of patients per year
would present with the condition (Dumbleton 2003).
The aetiology of SEALs is multifactorial, although
increasing lens modulus and excessive lens mobility appear
to be the most significant contributing factors. It is
believed that the following factors may all also predispose
to its occurrence: peripheral corneal topography, uppereyelid pressure and lens surface characteristics
(Dumbleton 2002, 2003, Holden et al. 2001, O’Hare et al.
2001, Young & Mirejovsky 1993).
Figure 2. Superior cornea following continuous wear of Comfilcon A
lens.
In general silicone hydrogel materials have a higher
modulus than hydrogel lenses (Table 1). First-generation
silicone hydrogel materials had higher levels of silicone to
provide sufficient oxygen transmissibility for oedema-free
overnight wear. Second-generation silicone hydrogel
lenses, eg the Lotrafilcon B and Galyfilcon A, had reduced
levels of silicone compared to the first-generation lenses
Lotrafilcon A and Balafilcon A (Steffen & Schnider 2004,
Steffen et al. 2004). As a result their modulus was lower
but so was their oxygen transmissibility, and these lenses
were only licensed for daily or occasional overnight wear.
BW was advised that he could continue lens wear and
should return for a routine check in 6 months’ time.
Six-month checkup: 03/12/2008
BW presented for his 6-month check. He was still wearing
the lens on a 30-day continuous-wear basis, happy with
both the VA and comfort.
His VA and acuity were as follows:
RE: VA 6/5 N5 with good range. OR plano
LE: no lens
Table 1. Moduli of some soft-lens materials
Material modulus
Lotrafilcon A (All Day All Night Air Optix)
Lotrafilcon B (Air Optix)
Comfilcon A (Biofinity)
Galyfilcon A (Acuvue Advance)
Senofilcon A (Acuvue Oasys)
Balafilcon A (Purevision) 1.1
Etafilcon A (Acuvue 2)
The centration and dynamic fit of the lens remained
unchanged. His bulbar and limbal conjunctival hyperaemia
were graded as 1.0 and 1.2 respectively. He had a small
area of inferior punctate staining graded as 1.4 but no
staining superiorly. There was no localised bulbar or limbal
hyperaemia or conjunctival staining under the upper lid.
Following lid eversion the papillary conjunctivitis was
graded as 0.5.
MPa
1.5
1.0
0.75
0.4
0.7
1.1
0.29
Data from French & Jones (2008): Etafilcon A data from manufacturer
29
N Best
References
The Comfilcon A material used in the above case would be
regarded as a third-generation silicone hydrogel lens. In
this lens the manufacturer has utilised long-chain siliconecontaining macromers to achieve high levels of oxygen
transmissibility from a lower concentration of silicone.
This has resulted in a significantly lower modulus and
higher water content than first-generation lenses.
Carnt N, Jalberty I, Stretton S et al. (2007) Solution
toxicity in soft contact lens daily wear is associated with
corneal inflammation. Optom Vis Sci 84, 309–15
Cheng KH, Leung SL, Hoekman HW et al. (1999)
Incidence of contact lens associated microbial keratitis
and its related morbidity. Lancet 354, 181–5
Some practitioners may question the need to manage a
SEAL which is generally asymptomatic, but it is well
documented that continuous wear is a risk factor for
corneal infiltrative events (Sczcotka-Flynn & Diaz 2007),
as are certain types of corneal staining (Carnt et al. 2007).
Therefore it would seem prudent to keep corneal staining
to a minimum in these patients.
Dumbleton K (2002) Adverse events with silicone hydrogel
continuous wear. Contact Lens Ant Eye 25, 137–46
Dumbleton K (2003) Non-inflammatory silicone hydrogel
contact lens complications. Eye Contact Lens 29 (Suppl.),
S186–9; discussion S190–1
Conclusion
Dumbleton KA, Chalmers RL, McNalley J et al. (2002a)
Effect of lens base curve on subjective comfort and
assessment of fit with silicone hydrogel continuous wear
contact lenses. Optom Vis Sci 79, 633–7
While the risk of microbial keratitis with continuous wear
of silicone hydrogel lenses is disappointingly similar to
hydrogel materials (Kodjikian et al. 2008, Schein et al.
1989, Stapleton et al. 2007) practitioners may now be in a
position to manage mechanical non-inflammatory
complications such as SEALs and papillary conjunctivitis,
which can occasionally result from the wear of firstgeneration lenses.
Dumbleton K, Jones L et al. (2002b) Silicone hydrogel
lenses: fitting procedures and in practice protocols for
continuous wear lenses. Optician 223, 37–45
Efron N, Morgan PB (2008a) Patterns of prescribing
extended wear contact lenses. Contact Lens Ant Eye 31,
167–9
The majority of first-generation silicone hydrogel lens
wearers do not experience the type of complications
described above, but practitioners faced with such a
condition could consider refitting their patient with a
third-generation silicone hydrogel lens. As there is no
evidence that these new materials have any effect on the
incidence of corneal inflammatory events or microbial
keratitis, the importance of careful patient selection,
education and regular follow-up remains the same.
Efron N, Morgan PB (2008b) Trends in the use of silicone
hydrogel contact lenses for daily wear. Contact Lens Ant
Eye 31, 242–3
French K, Jones L (2008) A decade with silicone hydrogels:
part 1. Optom Today 16, 42−6
Graham CM, Dart JK, Buckley CJ (1986) Extended wear
hydrogel and daily wear hard lenses for aphakia. Success
and complications compared in a longtitudinal study.
Ophthalmology 93, 1489–94
Harvitt DM, Bonanno JA (1999) Re-evaluation of the
oxygen diffusion model for predicting minimum contact
lens Dk/t values needed to avoid corneal anoxia. Optom Vis
Sci 76, 712–19
Holden BA, Mertz GW (1984) Critical oxygen levels to
avoid corneal oedema for daily and extended wear. Invest
Ophthalmol Vis Sci 25, 1161–67
Holden BA, Stephenson A, Stretton S et al. (2001)
Superior epithelial arcuate lesions with soft contact lenses.
Optom Vis Sci 78, 9–12
30
The Alleviation of SEALs
Tighe B (2004) Silicone hydrogels: structure, properties
and behavior. In: Sweeney D (ed.) Silicone Hydrogels:
Continuous Wear Contact Lenses. Oxford: ButterworthHeinemann, pp. 1–27
Jones L, Subbaraman LN, Rogers R et al. (2006) Surface
treatment, wetting and modulus of silicone hydrogels.
Optician 232, 28–34
Kodjikian L, Casoli-Bergeron E, Malet F et al. (2008)
Bacterial adhesion to conventional hydrogel and new
silicone hydrogel contact lens materials. Graefes Arch Clin
Ophthalmol 246, 267–73
Weissmann BA, Mondino BJ, Pettit TH et al. (1984)
Corneal ulcers associated with extended wear soft contact
lenses. Am J Ophthalmol 97, 476–81
Mordino MJ, Weissman BA, Farb MD et al. (1986) Corneal
ulcers associated with daily wear and extended wear
contact lenses. Am J Ophthalmol 15, 58–65
Young G, Mirejovsky D (1993) A hypothesis for the
aetiology of soft contact lens-induced superior arcuate
keratopathy. Int Contact Lens Clin 20, 177–80
O’Hare N, Naduvilath T, Sweeney DF et al. (2001) A clinical
comparison of limbal and paralimbal superior epithelial
arcuate lesions in high Dk extended wear. Invest
Ophthalmol Vis Sci 42, s595
Poggio EG, Abelson MB (1993) Complications and
symptoms in disposable extended wear lenses compared
with conventional soft daily wear and soft extended wear
lenses. CLAO J 10, 31–9
Schein OD, Glynn RJ, Poggio EC et al. (1989) The relative
risk of ulcerative keratitis among users of daily wear and
extended wear soft contact lenses. A case controlled study.
Microbial keratitis study group. N Engl J Med 321, 773–8
Sczcotka-Flynn L, Diaz M (2007) Risk of corneal
inflammatory events with silicone hydrogel and low Dk
hydrogel extended contact lens wear; a meta analysis.
Optom Vis Sci 87, 247–56
Stapleton F, Stretton S, Papas E et al. (2006) Silicone
hydrogel contact lenses and the ocular surface. Ocular
Surface 4, 24–43
Stapleton F, Keay L, Jalbert I et al. (2007) The
epidemiology of contact lens related infiltrates. Optom Vis
Sci 84, 257–72
Steffen R, Schnider C (2004) A next generation silicone
hydrogel for daily wear. Part 1 – material properties.
Optician 227, 23–5
Steffen R, Schnider C, McCabe K (2004) Finding the
comfort zone. Contact Lens Spectrum 13 (Suppl.), 1–4
Sweeney D, du Toit R, Keay L et al. (2004) Clinical
performance of silicone hydrogel lenses. In: Sweeney D
(ed.) Silicone Hydrogels: Continuous Wear Contact Lenses,
2nd edn. Oxford: Butterworth-Heinemann, pp. 164–216
31
Nigel Best
Multiple Choice Questions
This paper is reference C-10713. One credit is available. Please use the inserted answer sheet. Copies can be obtained from
Optometry in Practice Administration, PO Box 6, Skelmersdale, Lancashire WN8 9FW. There is only one correct answer for
each question.
1.
(a)
(b)
(c)
(d)
6.
Which of the following complications is not
associated with continuous wear of first-generation
silicone hydrogel lenses?
Mucin ball formation
Papillary conjunctivitis
Epithelial microcysts
SEALs
(a)
(b)
(c)
2.
(a)
(b)
(c)
(d)
3.
(a)
(b)
(c)
(d)
4.
(a)
(b)
(c)
(d)
5.
(a)
(b)
(c)
(d)
Which of the following statements regarding SEALs is
incorrect?
They are associated with lenses with higher moduli
They are a common cause of contact lens intolerance
Excessive lens movement predisposes to their
formation
They occur less frequently in hydrogel lens wearers
(d)
Which of the following would be regarded as firstgeneration silicone hydrogel lenses?
Balafilcon A and Comfilcon A
Lotrafilcon A and Omafilcon A
Senofilcon A and Galyfilcon A
Balafilcon A and Lotrafilcon A
Which of the following would be most likely to result
in SEAL formation?
Poor wetting
Peripheral corneal topography
Excessive lens movement
Upper-eyelid pressure
Which of the following lenses has the highest
modulus?
Lotrafilcon A
Balafilcon A
Senofilcon A
Lotrafilcon B
32
Regarding continuous wear of first-generation
silicone hydrogel lenses, which of the following
statements is false?
They are associated with a higher incidence of
papillary conjunctivitis than hydrogel lenses
Patients with handling difficulties may find these
lenses easier to insert and remove
They exceed the oxygen transmissibility requirements
for avoidance of corneal oedema
They are associated with a significantly lower risk of
microbial keratitis compared with hydrogel lenses
Optometry in Practice Vol 10 (2009) Issue 1
Multiple Choice Answer Sheet
Instructions
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the paper clearly marked at the top of each section.
Indicate your answer by filling in the relevant answer box, e.g.
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Make sure you fill in your address and, if appropriate, College membership number. Return this sheet to Optometry in
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0
1
D
1. Infection Control in
Optometric Practice
Question 1
Question 2
Question 3
Question 4
Question 5
Question 6
Question 7
Question 8
Question 9
Question 10
Question 11
Question 12
Question 13
Question 14
Question 15
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2. Legal Cases in Optical
Practice: Part One
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4. The Alleviation
of SEALs
3. Migraine
Question 1
Question 2
Question 3
Question 4
Question 5
Question 6
a
b c
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Volume 9 Issue 4
H. Radhakrishnan ‒ Myopia: An Overview
1.d 2.c 3.a 4.c 5.c 6.b 7.d 8.d 9.a 10.d 11.a 12.c
T.S. Kalyanasundaram ‒ Current Concepts in Age-related Macular Degeneration
1.c 2.d 3.b 4.b 5.c 6.d 7.b 8.a 9.d 10.c 11.c 12.d 13.b 14.d 15.d
D. Thomson ‒ The Ageing Eye
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E.L. Langley & M.J. Cox ‒ The Ocular Consequences of HIV/AIDS
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Optometry in Practice
Volume 10 Issue 1 pages 1 – 32
ST Parrish
ii
Editorial
Susan Blakeney
1 – 12
Infection Control in Optometric Practice
Rakesh Kapoor
13 – 18
Legal Cases in Optical Practice: Part One
Andrew Larner
19 – 26
Migraine
Nigel Best
The Alleviation of SEALs
27 – 32
ISSN 1467-9051
Optometry in Practice
2009 Volume 10 Issue 1 pages 1 – 32