I still use the same direct ophthalmoscope that I acquired during the second year of my optometry course at Aston in the late 1980s. The range of lenses and stops makes it useful for general screening and the focusing is now something I can do on automatic. I have to say that I increasingly use the direct instrument almost as a screening tool and prefer to use a slit lamp and fundus viewing lens for a good view.
This has the advantage of a binocular view, even with mid-sized pupils, but more importantly for me, I can get a better view of the fundus through the many less than transparent crystalline lenses that turn up at our clinic. I am convinced that had the direct not been the sole ophthalmoscope I was trained with at university, it would now be my second choice for fundus viewing.
The Optyse
There has been some publicity over recent months about a low-cost lens-free ophthalmoscope which is being used in developing countries and overseas programmes in eye care screening where budgets are limited. I noticed that the instrument is now being marketed in the UK and was keen to try one out. 
The instrument itself is a similar size to a pen torch (Figure 1) and comes in a slip-in case which may fit into or onto the breast pocket. The unit has lens cover which is rotated over the handle before use (Figure 2). It takes two AAA batteries which offer up to four hours' continual use. The unit contains a miniature 2.5 volt lamp which, as with a standard direct ophthalmoscope, should last for years, but replacements are easily available and easy to obtain and replace.
The unit consists of the lamp, light from which is reflected from a prism directly above it towards the patient's eye. The viewing hole allows the practitioner to look immediately over the prism edge to see the area illuminated (presumably the 
patient's fundus). The prism is visibly yellow, as is the light projected into the patient. This is deliberate as the Optyse claims to 'minimise' ultraviolet radiation and short wavelength visible light (less than 420nm) as a safety precaution. The radiance as a function of typical time exposure is similar to that of other direct ophthalmoscopes, so there appear to be no safety concerns with the Optyse.
Using the Optyse
As someone used to a focusing instrument, it took a long time to get used to a lens-free instrument. My finger continued to search for the lens wheel. As this is a single focus instrument, both patient and practitioner need to be emmetropic to ensure an accurate retinal view. Furthermore, it is not possible to focus easily on more anterior structures, say a large vitreous floater or the crystalline lens. It is therefore important 
that any refractive error is corrected by the practitioner and patient keeping on their spectacles or contact lenses. In the case of spectacles, this undoubtedly reduces somewhat the field of view obtainable through the instrument. For high refractive errors, contact lenses allow a still accurate resolution of retinal detail, but this was trickier through spectacles.
My old ophthalmoscope is of such a shape that if I ram it into the upper corner of my orbit, the viewing hole is directly in front of my eye (Figure 3). The Optyse is much smaller and the viewing hole much closer to the end of the instrument. It is worth spending a few moments before using it on a patient to ensure the instrument positioning is comfortable (Figure 4). What I initially took to be a poor view was actually, in most cases, a result of my positioning the 
instrument incorrectly. Once in the correct position, the patient's eye is approached as with any other direct ophthalmoscope (Figure 5).
Performance
I managed an excellent view of the disc and macular areas on everyone I examined. The key is for the patient correction to be in position. As soon as there is more than around 1 dioptre of blur, the image is increasingly difficult to interpret. I looked at a series of patients with known specific pathologies but unknown to myself before trialling the instrument.
It was easy to detect the small area of myelination next to the disc of a young emmetrope. It was similarly easy to accurately observe and record the symmetrical but significantly cupped discs of a middle-aged myope (corrected with contact lenses). A congenital hypertrophy of the retinal pigment epithelium was not detected in its mid-peripheral location, but could be seen with my old direct ophthalmoscope. The patient in this case was undilated and had scotopic pupil size of around 5mm.
In general, I would say that for corrected or emmetropic patients the instrument is excellent for posterior pole, disc and macular viewing. The image is clear enough for detecting smaller lesions, the magnification and field being comparable to that of a standard direct ophthalmoscope. For more peripheral lesions in undilated patients, and for assessing patients with significant uncorrected refractive error, the instrument does not allow an adequate view.
I loaned the instrument to a general practitioner colleague of mine who openly professes to have problems with his 'focusable' ophthalmoscope. After a week in general practice, he reported that he had tried it on about eight occasions and he described the Optyse as easy to use and useful.
I suggest that this little instrument would be useful for anyone wishing for a cheap screening ophthalmoscope which, in optometric practice, might aid pre-assessment before a more thorough assessment, perhaps with a binocular indirect method as first choice. I could happily use the Optyse and buy a second fundus viewing lens with the money saved (the Optyse is retailing at £38+VAT). For ancillary staff and related medical professionals for whom ophthalmoscopy is useful but not integral to their role, I would say this was an effective instrument. I can also say that where budgets are restricted, as in some overseas eye care programmes, the Optyse should significantly improve the standard of care.
For more information on the Optyse contact Altomed on 0191 519 0111.