We seem to have generated some healthy debate with our recent publication of articles looking at the E-Scoop lenses. These feature a yellow tint to enhance contrast for patients, particularly those with maculopathy, and also have a bilateral prism incorporated. The aim of the prism is to project the image onto the retina outside the atrophic macula so enhancing vision.
Theoretically, this is problematic and, indeed, I have some concerns over this. Bilateral prism will indeed change the angle of the incident beam and is useful, for example, in overcoming diplopia by adjusting the incident angle to meet the angle of deviation for one eye in a recent onset tropia, for example. The problem with using this bilaterally for eccentric viewing is that, in my humble view, it is most likely to simply adjust the binocular viewing gaze rather than encourage eccentric viewing.
Recent studies have looked at the whole area of eccentric viewing and raised some questions. A nice paper soon to be published by Professor Chris Dickinson and Dr Ahalya Subramanian has suggested that the main benefit of any eccentric viewing training strategy, typically using targeted focus based on a clock face assessment of residual retinal preference, is of a subjective nature – patients report benefit in having their problems looked at but with no functional or measurable improvement. Similar results seem to be coming from the work of Gary Rubin recently published at ARVO.
That said, subjective benefit is still a benefit. There is an ever-increasing number of patients reporting significant improvement with the lenses. At the recent European optometry conference, I met up with a German practitioner reporting amazing results with the E-Scoop. It seems to me we are moving towards a familiar problem. Should we deny patients the opportunity to try a solution they may find benefit from even when the evidence base does not support any benefit?