Changes in the Visual Evoked Response During and After Occlusion Therapy for Amblyopia

Abstract

The VER was studied in normal children aged 4--11 years and in 71 amblyopic children at Moorfields Eye Hospital. Changes in the VER in amblyopia are best observed with 20% contrast and small square sizes. The better eye of untreated amblyopia has a normal time-to-peak for P1 of the cortical response, while that of the amblyopic eye is delayed, the more so with poor binocular vision in partial agreement with our previous findings. We found with a high degree of significance that occlusion therapy renders the VER from the amblyopic eye more 'normal' but causes considerable delay in the VER from the covered eye, even though its visual acuity does not change. At the end of occlusion, these changes are usually reversible although not always completely in patients who have had prolonged occlusion.

Continuous Full-Time Occlusion of the Sound Eye Vs Full-Time Occlusion of the Sound Eye Periodically Alternating with Occlusion of the Amblyopic Eye in Treatment of Amblyopia: A Prospective Randomized Study

“…First, the mean value of PVEP latencies of the sound eye in the experimental group showed growth trend, opposite to the control group. Arden and Barnard (29,30) also reported the same changes in the visually evoked response after continuous occlusion. Although these tendencies did not show significant statistical difference in our study, in their absence interocular initial and final latencies difference would not show significant statistical improvement.…”

Temporal Ventriloquism Reveals Intact Audiovisual Temporal Integration in Amblyopia

“…31 In amblyopia, the neural mechanism for cross-modal matching may be miscalibrated in early life under the influence of increased temporal jitter 15,17 and interocular latency differences. 41,42 If audiovisual cross-modal matching is calibrated before the end of the sensitive period for amblyopic visual recovery, 43 then therapy that improves vision, equalizes evoked response latencies, 44,45 and reduces internal temporal noise 16 may not narrow the audiovisual temporal binding window. Such asynchronous sensitive periods for unisensory and multisensory functions may therefore explain how cross-modal matching may be selectively impaired, and why the deficit persists under binocular viewing conditions that provide highfidelity temporal information from the fellow eye.…”