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Diabetes in primary Care Practice
Dr Simon Barnard
Life can be too sweet
Diabetes in primary care optometric
Dr Simon Barnard
PhD BSc FCOptom FAAO DCLP DipClinOptom
Clarion Hotel
Oslo
Thursday 24 January 2002
Oslo
1
24 January 2002
Diabetes in primary Care Practice
Dr Simon Barnard
Table of Contents
Table of Contents .............................................................................................. 2
Introduction ....................................................................................................... 3
Epidemiology ..................................................................................................... 3
Prevalence ..................................................................................................... 3
Incidence of blindness ................................................................................... 3
Non-Insulin Diabetes Mellitus (NIDDM) ............................................................. 3
Insulin-Dependent Diabetes Mellituis (IDDM) .................................................... 4
Ocular manifestations of diabetes ..................................................................... 4
Introduction .................................................................................................... 4
Retinal manifestations ................................................................................... 5
Fundoscopy ....................................................................................................... 6
Advantages of indirect versus direct ophthalmoscopy ................................... 6
Indications for referral........................................................................................ 7
Guidelines of the European Working Party for Screening for diabetic
retinopathy ..................................................................................................... 7
Informing the GP & Diabetic Physician .......................................................... 8
Useful contact.................................................................................................... 8
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24 January 2002
Diabetes in primary Care Practice
Dr Simon Barnard
Introduction
Diabetic care forms an increasingly important part of general optometric practice
with optometrists in some areas of the UK, and indeed across the world in the
USA, Canada, Australia and some EC countries such as the Netherlands,
examining the majority of diabetics seen for their eye care.
In certain Area Health Authorities in the UK there are formal “Shared Care”
schemes where the optometrist is paid an additional fee for just carrying out
fundoscopy on diabetics.
Epidemiology
Prevalence
1% of the 60 million population in the UK suffers from Diabetes. The prevalence
increases with age to 3 to 4% of the population over the age of 40 years.
Norway, with a population of 4.5 million inhabitants has approximately 130,000
people with diabetes. This amounts to some 2.9% of the population. About
0.45% have IDDM and 1.8% suffer from NIDDM. It is estimated that a further
0.65% of the population are undiagnosed.
Incidence of blindness
In the UK there are 1500 new cases of blindness per year.
Non-Insulin Diabetes Mellitus (NIDDM)
These patients can survive without exogenous insulin although many eventually
require insulin to improve control. The prevalence in the UK is approximately 1%
in UK and in Norway 1.8 %.
The prevalence in elderly and some groups in the UK, for example Asian
communities are higher at around approximately 3 to 5%.
The prevalence in Lima Indians of Arizona is reportedly 50%.
Migrants to western world seem to be particularly susceptible.
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Diabetes in primary Care Practice
Dr Simon Barnard
NIDDM is correlated with a combination of relative insulin deficiency and insulin
resistance. The latter may be exacerbated by obesity.
There is a strong genetic predisposition with twin concordance for NIDDM being
90% compared to only 40% for IDDM.
NIDDM accounts for about 75 to 80% of the diabetic population.
NIDDM gives high risk of macrovascular complications and usually presents as a
syndrome of anomalies including hypertension, hyperlipidaemia, obesity, and
insulin resistance.
Very often optometrists will hear from their patient that “ I have a just a little
sugar” or “I have mild diabetes”. In fact, there is no such thing as “mild diabetes”.
Whatever the control required, if not adhered to, the disease will lead to retinal
and other damage.
Insulin-Dependent Diabetes Mellitus (IDDM)
These patients cannot survive without insulin. In the UK the prevalence is about
0.2% with an incidence of 15/100,000/year aged < 21. Most cases present before
30 years and there is a peak incidence at 11-13 years.
A possible cause is destruction of the  cells of the Islets of Langerhans perhaps
through an autoimmune response.
Retinopathy is unusual before puberty and usually only presents after at least 10
years.
Mortality in < 50 age group is about 5 x higher than non-diabetics.
Ocular manifestations of diabetes
Introduction
Although we often think of retinal changes, it must not be forgotten that other
parts of the eye and visual system may be affected including the anterior
segment with changes occurring to the iris and lens. Changes in the iris include
micro aneurysms and neovascularisation, the latter leading to a secondary
glaucoma.
The classic “diabetic snowflake cataract” that occurs in acute diabetes is rarely
seen. If the patient is swiftly treated, the cataract substantially resolves. Diabetics
tend to develop prematurely age related lens changes.
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Diabetes in primary Care Practice
Dr Simon Barnard
The optometrist is often the first person to suspect diabetes in a patient because
of apparent fluctuations in refraction, along with reported symptoms of an
unusual thirst and possible a general feeling of malaise or repeated illnesses.
The visual pathway may be affected in a variety of ways with, for example,
haemorrhages producing visual field defects. Similarly diabetics are more prone
to suffering lesions of the ocular motor system with consequent gaze palsies and
incomitant strabismus.
Retinal manifestations
Retinal signs may be categorised into:(1)
non-proliferative
(a)
background
(b)
pre-proliferative
(2)
proliferative
Let us look at each of these.
Background diabetic retinopathy
This manifests as:




dot and blot haemorrhages.
micro aneurysms are also present and are more prevalent temporally.
lipid exudates, sometimes call hard exudates may also be present.
macular oedema may occur and be focal or diffuse.
Pre-proliferative diabetic retinopathy
This manifests as




more marked background retinopathy but now with the addition of
“cotton wool spots” which represent nerve fibre infarction with axonal
debris.
IntraRetinal Microvascular Anomalies (IRMA)
Venous beading and looping
Proliferative diabetic retinopathy (PDR)
The term proliferation describes the appearance of “new vessels” or
“neovascularisation”. These vessels emanate from retinal venules..
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Diabetes in primary Care Practice

Dr Simon Barnard
Neovascularisation can occur on the disc (NVD) or as neovascularisation
elsewhere (NVE).
These vessels are fragile and are prone to bleed into the sub-hylaoid space,
giving



a flat topped or sub-hylaoid haemorrhage. These can break through into
the vitreous to produce a
vitreous haemorrhage which will resolve with cicatricisation, and as the
fibrous tissue contracts will cause traction leading to
retinal detachment
Fundoscopy
It is necessary to dilate diabetics’ and before doing so the optometrist should
check the anterior chamber angle with the slit lamp (Van Herrick technique) and,
if the angle appears narrow, with gonioscopy.
Drugs of choice to dilate are the anti-muscarinic, Tropicamide 0.5% or 1% and
The sympathomimetic, phenylephrine hydrochloride 2.5%. These can be used
synergistically to produce maximum dilatation.
However, patients with advance diabetic disease, with signs such as peripheral
neuropathy, may be “super-sensitive” to sympathomimetics. Phenylephrine
should be avoided in these cases because of the risk of adversely affecting the
cardiovascular system.
As a rule, the optometrist should check the systemic blood pressure of all
patients over 40 years of age before using phenylephrine.
Advantages of indirect versus direct ophthalmoscopy
The best way of examining the diabetic fundus is with a slit lamp lens such as the
Volk 66, 70 or 90 D or with contact fundus lens. The direct ophthalmoscope may
be used but really is quite inferior.
Whilst the direct opthalmoscope gives a field of view of about 10 degrees, this
compares with the better field of view around 120 degrees with some slit lamp
fundus lenses. Similarly indirect provides stereopsis and better illumination.
Retinal photography is also invaluable for screening for and recording changes.
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Diabetes in primary Care Practice
Dr Simon Barnard
Indications for referral
Guidelines of the European Working Party for Screening for diabetic
retinopathy
Immediate referral
Sight threatening retinopathy
Proliferative retinopathy
NVD
NVE
Pre-retinal haemorrhage
Fibrous tissue
Vitreous haemorrhage
Fibrous tissue
Recent retinal detachment
Rubeosis iridis
Early referral
Lesions likely to be threatening within twelve months
Pre-proliferative retinopathy
Venous irregularities (beading, loops collaterals)
Multiple haemorrhages
Multiple cotton wool spots
IRMA
Non-proliferative retinopathy with macular involvement
Reduced VA (? = macular oedema)
Lipid of haemorrhage within 1 disc diameter of macular
Non-proliferative retinopathy without macular involvement
Circinate or plaqued lipid within major temporal arcades
Any other finding observer unsure of
Lesions not requiring referral to the ophthalmologist
Non-proliferative retinopathy
Small numbers of cotton wool spots not associated with pre-proliferative changes
Occasional haemorrhages/micro aneurysms and lipid not within 1 DD of macular
Drusen
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Diabetes in primary Care Practice
Dr Simon Barnard
Informing the GP & Diabetic Physician
In the UK it is mandatory to write a report the patient’s GP following an eye
examination. A copy sent to the diabetic physician will be useful/.
It should be remembered that although ophthalmological attention may not be
necessary, modifications to the general diabetic regime of therapy are sometimes
required.
Useful contact
Norges Diabetesforbund
Postboks 6442 Ettersad
N-0605 Oslo
Tel +47 23 05 18 00
Dr Simon Barnard
e-mail [email protected]
January 2002
Oslo
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24 January 2002