Optos case study 3 Tumour or cyst?

Jonathan Pilbeam reports how one early referral based on findings with the Optos system helped his subsequent patient management

For decades, optometrists have been charged with the task of detecting disease and abnormality of the eye and referring when necessary. In the past, our main investigative tool has been the direct ophthalmoscope and generations of optometrists have become experts in interpreting the small amount of fundus that is visible at any one time.

In recent years a plethora of new techniques have become more widely available including headset indirect, Volk lens and digital imaging systems. These have revolutionised the view available to the clinician. As well as seeing much more of the fundus, we are also detecting many more retinal features that were previously almost confined to the textbooks as they were so difficult to view using traditional methods.

When we were one of the first practices in the UK to take on the Optomap laser scanning system, Optos advised us of the steep learning curve that we would encounter in interpreting the ultra-wide field fundus images demonstrating previously undetected features. The skill in using such a system comes in interpreting these features and deciding whether they are part of a 'normal' retinal picture, or benign lesions that we can monitor, or pathology that needs referral.

One of the earliest people who presented us with this dilemma was a 59-year-old asymptomatic hyperopic patient who presented for a routine eye examination. Direct ophthalmoscopy detected no apparent abnormality. However, Optomap imaging revealed the initially alarming picture, shown in Figure 1. Was it a detachment or even a large malignant melanoma, or was it something altogether more benign?

The patient was urgently referred for the opinion of an ophthalmologist. Unfortunately, we did not receive a report back from the hospital and we had to rely on the patient's report of a 'cyst - and nothing to worry about'. It has since transpired that what we were looking at was a retinoschisis - present in about 5 per cent of the population over 20 years and more prevalent in hyperopes (70 per cent).

Retinoschisis is a split within the sensory retina resulting in an outer choroidal layer of retina and an inner vitreous layer of retina. This is quite distinct from a retinal detachment where the sensory retina (layers 1 to 9) come away from the pigmentary layer (layer 10). The condition is often first noticed at the extreme infero-temporal periphery of the fundus appearing as a smooth elevation of the retina.

This is clearly illustrated in the different appearance of the red and green separation in Figure 2 and Figure 3 where the retinoschisis is more prominent in the red (choroidal) image. Although the lesion may eventually involve the entire fundus periphery, the typical form usually remains anterior to the equator. Although retinal detachment is a very rare complication of retinoschisis, the condition is usually innocuous and asymptomatic.

The result of this case was a more informed practitioner and a patient who was impressed that the condition was detected in the first place; and who is more than happy now to pay for retinal scanning to see how his 'cyst' is getting on.

Our practice now utilises the facility provided by Optos whereby we can email an image to a retinal specialist in the US who provides a second opinion, usually within 24 hours. This, together with our five years of experience in using the system, has now led to a much reduced referral rate for ophthalmological opinion.

*Jonathan Pilbeam is an optometrist practising in Loughborough