Bill Harvey: How eccentric is vision training?

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.