Download Thomas Salisbury

Fig 1: Illustration demonstrating an early direct ophthalmoscope [1]
“Does direct ophthalmoscopy have a role in the
modern NHS?"
October 2016
1
Thomas Salisbury
[email protected]
1.
Ruete, C.G.T., Der Augenspiegel und das Optometer für practische. 1852.
History of Ophthalmoscopy
2
Today a skilled practitioner of direct ophthalmoscopy (DO) may use the ophthalmoscope to
peer into the eye and view the fundus. However, as with most modern inventions, the direct
ophthalmoscope, as we know it today, was reached through many iterations, as aptly shown
in figure 2 below.
Figure 2: History of Ophthalmoscopy [2]
In 1825 Jan Purkinje first observed a human fundus using concave spectacles, but this was
unrecognised until later. It was not until twenty six years later that Hermann von Helmholtz
was accredited with discovering the ophthalmoscope and illuminating the mystery of what
lay behind the pupil [3]. The direct ophthalmoscope has through its iterations utilised
different light sources ranging from candle to the modern bulb and now LEDs. Correcting a
patient’s refractive error was overcome by mounting a rotating disc onto the
ophthalmoscope, this was invented by Egbert Rekoss one hundred and fifty years ago and is
2.
3.
Mackay, D.D., et al., The demise of direct ophthalmoscopy A modern clinical challenge. Neurology: Clinical Practice, 2015. 5(2):
p. 150-157.
Keeler, C., A Brief History of the Ophthalmoscope. Optometry in Practice, 2003. 4: p. 137-145.
still in use today. Equally, the slit lamp was first put forward as an idea in 1911 by Allvar
Gullstrand and has gone on to become, along with the binocular indirect ophthalmoscope
(first built in 1947), the standard method by which modern ophthalmologists examine the
fundus [3]. Table 1 below outlines the various methods of viewing the fundus as well as a brief
overview of their advantages and disadvantages.
Advantages
Mag x15, Erect image, Portable,
Manoeuvrable, Widely
available, relatively low cost,
quickly utilized
Disadvantages
Depth only through parallax,
limited field of view, Record
keeping only in drawing,
Difficult to master
Monocular indirect
Increased field of view, Erect
real image
Same as Monocular direct, less
magnification
Binocular Indirect slit
lamp
Wider field of view, peripherals
available such as tonometry and
gonioscopy, Powerful
illumination, Stabilising rest,
Stereopsis, allows variety of
illumination from indirect to
specular.
Wider field of view, Hand freed,
stereopsis
Good field of view depending on
system, Easy image storage and
manipulation, Good sensitivity
allowing less light to be used
and fainter images can be
captured, Relatively quick to
learn (point, adjust, shoot)
Mag dependant on lens used,
Inverted image, Record
keeping only in drawing
(unless digital slit lamp),
Requires practice to be
competent
Ubiquitous nature of smart
phones, relatively low cost,
digital records, telemedicine
possibilities
Data protection issues,
Requires further clinical trials
Monocular direct
Binocular Indirect
headset
Digital imaging
Mobile imaging
Same as slit lamp
Difficult if patient has physical
issues with mobility e.g.
(tremor, uncooperative, neck
issues), limited stereopsis
depending on system, High
cost, Difficulties with media
opacities
Table 1: Advantages and disadvantages of fundal imaging methods
3
3.
Keeler, C., A Brief History of the Ophthalmoscope. Optometry in Practice, 2003. 4: p. 137-145.
Future of Ophthalmoscopy 4
It is worth noting that among the alternatives to DO, digital imaging is rapidly becoming a
broad field covering many differing modalities such as Fundus photography, scanning laser
ophthalmoscopy and optical coherence tomography (OCT). Future imaging modalities are still
being developed and entering into common use, such as Doppler OCT and adaptive optics [4].
Other more accessible options are currently emerging into the market, I.e. mobile imaging
such as the D-Eye [5] or Peek[6], which are adaptors enabling smart phones to take fundus
photographs. They show significant promise in the third world as specialised imaging is less
available and mobile imaging enables remote review of images. The role of mobile imaging
within the NHS, however, is limited as purchasing a departmental smart phone and camera
adapter would come to a similar cost as a direct ophthalmoscope. It would also incur
additional costs such as a software infrastructure in order to handle image storage. However,
were these barriers to be addressed, smart phone fundal imaging may provide a strong
competitor to DO.
Cost
In today’s NHS cost efficacy is more important than ever. DO is widely available and relatively
(£500) inexpensive compared to slit lamp imaging (£2000-£8000+) and fundus cameras
(£3000-£12000+). Also, with the above imaging modalities the cost of the equipment needs
to be balanced against the training costs. DO is a skill that is taught at medical school where
teaching may vary significantly and, like most things in medicine, effective use benefits from
practice on a variety of patients. Medical graduates who do not engage in extracurricular
learning in addition to normal medical education, show a lack of confidence in their findings
and on the whole all students prefer fundus photographs for both learning and examining the
ocular fundus [7, 8]. Also, due to the removal of ophthalmology being a requirement in
4.
5.
6.
7.
8.
Calcagni, A. and J. Gibson, Imaging of the human fundus in the clinical setting: past, present and future. US ophthalmic review,
2013. 6(1): p. 42-47.
Andrea Russo, F.M., Ciro Costagliola, Mario R Romano, Iari-Gabriel Marino, Francesco Semeraro, Comparison of Smartphonebased Ophthalmoscopy VS Dilated Ophthalmic Examination to Detect Ocular Pathologic Features, in AAO 2014: Chicago.
Lodhia, V., et al., Acceptability, Usability, and Views on Deployment of Peek, a Mobile Phone mHealth Intervention for Eye Care
in Kenya: Qualitative Study. JMIR mHealth and uHealth, 2016. 4(2).
Kelly, L.P., et al., Teaching ophthalmoscopy to medical students (the TOTeMS study). American journal of ophthalmology, 2013.
156(5): p. 1056-1061. e10.
Gupta, R. and W.-C. Lam, Medical students' self-confidence in performing direct ophthalmoscopy in clinical training. Canadian
Journal of Ophthalmology/Journal Canadien d'Ophtalmologie, 2006. 41(2): p. 169-174.
undergraduate training [9] few medical students get a rotation in this specialty which is
possibly propagating the view that ophthalmological issues are simply the realm of
ophthalmologists leading to a lack of confidence in dealing with sight threatening issues when
trained in another speciality [10].
Uses of Ophthalmoscopy 5
As the NHS and private sector have changed and diagnostic imaging has become ubiquitous
in most ophthalmic settings from optometrists to ophthalmology units and it would not be a
fair review of the role of DO in the NHS if the various settings it is used in were not addressed
individually, these are discussed below:
Screening
Wilsons widely known criteria in screening for diseases is what the Liverpool Diabetic Eye
Study looked to evaluate DO and fundal imaging against (among several other outcomes).
This study is what led to the introduction of screening for diabetic eye disease in the UK and
worldwide. Photography as used in the Liverpool diabetic eye study achieved a high sensitivity
of 89% compared to the 65% achieved with DO in detecting early degrees of sight threatening
maculopathy accurately. Photography however struggled to acquire images in with difficulties
such as posture, tremor and media opacities [11]. It also must be noted that this study only
looked at diabetes and not at other specific sight threatening issues that DO may be more
beneficial in visualising.
Primary Care
Few GPs, without a specialist interest, have the time and resources to perform anything more
than DO, as few will have more advanced equipment or the appointment times to perform
proper mydriatic DO.
9.
10.
11.
GMC, Tomorrow’s doctors: Outcomes and standards for undergraduate medical education. . General Medical Council, 2009.
Chan, T., et al., Needs assessment of ophthalmology education for primary care physicians in training: comparison with the
International Council of Ophthalmology recommendations. Clin Ophthalmol, 2011. 5: p. 311-9.
Harding, S., et al., Sensitivity and specificity of photography and direct ophthalmoscopy in screening for sight threatening eye
disease: the Liverpool Diabetic Eye Study. Bmj, 1995. 311(7013): p. 1131-1135.
Ophthalmology Department use
Within ophthalmology units there is a reliance on other techniques for ocular examination,
namely binocular indirect slit lamp, indirect headset and digital imaging.
Non Ophthalmology Specialties
Most inpatients examined by ophthalmology are seen in consultation at the request of
another medical specialty. However, Specialties such as neurology still have a use for DO as
there is a definite need to see the fundus on a relatively regular basis.
Optometrists
Optometrists still widely utilise DO as part of routine examinations on a daily basis regardless
of further imaging performed. Independent optometrists as well as the large chains have
differing levels of finances available to invest in a digital imaging foundation for their
practices. Even so, fundus photography of has found its way into many practices over the past
few years. Currently there is no peer-reviewed, scientific evidence that shows digital imaging
is effective for all patients as a stand-alone technique for examination of the fundus in the
community [12]. The majority of these photography services are charged as extras on top of
what is considered an appropriate optometric eye test. However, certain practices that have
the infrastructure, such as vision express, are offering free retinal photography with sight
tests to attract customers. The question, therefore, is at what point the clinical benefit to the
patient requires fundal photography to become mandatory in addition to, or even in place of,
DO and for this to be included in NHS sight tests. More clinical trials, a more favourable cost:
benefit ratio and the breaking of tradition could facilitate this transition.
Legal Aspects of DO 6
Returning briefly to the history of ophthalmoscopy, it was Keeler who introduced the Morgan
Retinal Graticule to allow locating and measuring features on the retina. This was one of the
first attempts at addressing the issue of record keeping of ophthalmic lesions [13].
6
12.
13.
14.
Ontario, C.o.O.o. Digital Imaging/Fundus Photography in Optometric Practice. 2008; Available from:
http://www.collegeoptom.on.ca/members/professional-practice/policy/286-digital-imaging-fundus-photography-inoptometric-practice/.
Morgan, O.G., A retinal graticule. The British journal of ophthalmology, 1927. 11(7): p. 339.
Davis, F.D. and V. Venkatesh, A critical assessment of potential measurement biases in the technology acceptance model: three
experiments. International Journal of Human-Computer Studies, 1996. 45(1): p. 19-45.
Now with digital imaging, part of what might drive fundal photography to become a standard
in NHS examinations is the legal protection that fundal photography provides in contributing
to good record keeping, as well as a temporal record of retinal changes through a patient’s
lifetime.
Conclusion
It is likely that all the current and future technologies will continue to be improved upon and
combined into increasingly sophisticated instruments. The exponential advancement of
human technology and Moore’s law relating to transistor density will in turn effect the pricing
and availability of electrical goods such as the nonmydriatic fundus camera. Depending on
the rate of technological acceptance, digital photography may at some point replace DO in
many clinical settings. However, this is affected by a variety of external and internal factors
as shown by the technological acceptance model shown in Fig 3.
Figure 3: Technological acceptance model (TAM) [14]
The direct ophthalmoscope is subject to the inexorable advance of technological progress
and in the years to come will inevitably be balanced against alternatives based on its cost
and utility. However, the direct ophthalmoscope will, for the foreseeable future play a role
in the NHS as its portability, cost, utility and familiarity is unmatched by any of the current
alternatives.
Word count: 1495
References
1.
2.
3.
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5.
6.
7.
8.
9.
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11.
12.
13.
14.
Ruete, C.G.T., Der Augenspiegel und das Optometer für practische. 1852.
Mackay, D.D., et al., The demise of direct ophthalmoscopy A modern clinical challenge.
Neurology: Clinical Practice, 2015. 5(2): p. 150-157.
Keeler, C., A Brief History of the Ophthalmoscope. Optometry in Practice, 2003. 4: p. 137145.
Calcagni, A. and J. Gibson, Imaging of the human fundus in the clinical setting: past, present
and future. US ophthalmic review, 2013. 6(1): p. 42-47.
Andrea Russo, F.M., Ciro Costagliola, Mario R Romano, Iari-Gabriel Marino, Francesco
Semeraro, Comparison of Smartphone-based Ophthalmoscopy VS Dilated Ophthalmic
Examination to Detect Ocular Pathologic Features, in AAO 2014: Chicago.
Lodhia, V., et al., Acceptability, Usability, and Views on Deployment of Peek, a Mobile Phone
mHealth Intervention for Eye Care in Kenya: Qualitative Study. JMIR mHealth and uHealth,
2016. 4(2).
Kelly, L.P., et al., Teaching ophthalmoscopy to medical students (the TOTeMS study).
American journal of ophthalmology, 2013. 156(5): p. 1056-1061. e10.
Gupta, R. and W.-C. Lam, Medical students' self-confidence in performing direct
ophthalmoscopy in clinical training. Canadian Journal of Ophthalmology/Journal Canadien
d'Ophtalmologie, 2006. 41(2): p. 169-174.
GMC, Tomorrow’s doctors: Outcomes and standards for undergraduate medical education. .
General Medical Council, 2009.
Chan, T., et al., Needs assessment of ophthalmology education for primary care physicians in
training: comparison with the International Council of Ophthalmology recommendations.
Clin Ophthalmol, 2011. 5: p. 311-9.
Harding, S., et al., Sensitivity and specificity of photography and direct ophthalmoscopy in
screening for sight threatening eye disease: the Liverpool Diabetic Eye Study. Bmj, 1995.
311(7013): p. 1131-1135.
Ontario, C.o.O.o. Digital Imaging/Fundus Photography in Optometric Practice. 2008;
Available from: http://www.collegeoptom.on.ca/members/professionalpractice/policy/286-digital-imaging-fundus-photography-in-optometric-practice/.
Morgan, O.G., A retinal graticule. The British journal of ophthalmology, 1927. 11(7): p. 339.
Davis, F.D. and V. Venkatesh, A critical assessment of potential measurement biases in the
technology acceptance model: three experiments. International Journal of Human-Computer
Studies, 1996. 45(1): p. 19-45.