Predicting Stereopsis in Macular Degeneration

Binocular visual function and fixational control in patients with macular disease: A review

“…Additionally, Silvestri et al 22 found a similar proportion of patients exhibiting binocular summation and binocular inhibition for MRS, at 42% and 41%, respectively. Patients with binocular inhibition also show a significantly lower binocular MRS than the summation and equality groups, as shown in Figure 1 18,25 . Likewise, a similar pattern of results was found for CPS and reading acuity 21,22 .…”

“…Poor or no stereopsis is observed in patients with macular degeneration, particularly those with large asymmetry in retinal damage between the two eyes 22 44 and if the distance between intact retinal locations is less than the upper disparity limit at the corresponding eccentricity 18 …”

“…There is potential for rehabilitation in some patients with stereopsis. For patients with an intact retina below the upper disparity limit, they can perhaps be trained to use alternate PRLs that fall within this limit to regain stereopsis 18 …”

“…22 The potential for at least coarse stereopsis in these patients may depend on whether they have intact visual function in roughly corresponding points in the two retinas (i.e., the PRLs fall on functional retina and corresponding positions in the two eyes), 44 and if the distance between intact retinal locations is less than the upper disparity limit at the corresponding eccentricity. 18 Coarse stereopsis in patients with central vision loss is important for performing tasks of daily living. The absence of stereopsis in patients with macular degeneration with bilateral vision impairment has been associated with reduced overall quality of life, with these patients scoring low on reading ability scores.…”

“…This difference may arise from corresponding PRLs falling onto unequally functional retinal locations or from the PRL of the worse eye falling directly onto the scotoma when coming into retinal correspondence with that of the better eye during binocular viewing. For these patients, high interocular asymmetry, 17 and possible abnormal disparity produced by eccentric locations of the PRL in the two eyes 18 can affect binocular summation and stereopsis. Unfortunately, these binocular functions and oculomotor control of patients with macular disease are not well understood.…”