Evaluation of motion perception and binocular vision following dichoptic treatment for amblyopia

Although poor monocular visual acuity is the main characteristic of amblyopia, binocular vision is also often disrupted in amblyopia. Motion perception deficits have also been reported to be impaired in both amblyopic and fellow eyes. Occlusion therapy, the gold-standard treatment for amblyopia, is usually unsuccessful at fully restoring binocular visual function or motion perception. We evaluated the effectiveness of a video game-based dichoptic treatment (Vivid Vision) for restoring these aspects of vision in amblyopia. Twenty-one participants (age 6 to 56 years) with strabismic, anisometropic or aniso-strabismic amblyopia were assessed before and after 8 weeks of binocular treatment. Treatment was not part of the research protocol and comprised at least 4 h of training through a local optometry practice in the clinic or at home. Monocular visual function measures included visual acuity, and coherence thresholds for discriminating motion-defined form orientation or global motion direction. Binocular measures included stereoacuity and interocular suppression measured as a contrast balance index on a dichoptic eye chart. Group analyses revealed abnormal performance before the treatment, relative to a large control dataset (N = 217), on every measure except fellow-eye visual acuity. After the treatment, there was a significant mean improvement in amblyopic-eye visual acuity, amblyopic-eye motion-defined form perception and fellow-eye global motion perception, with some participants improving to normal performance levels. Interocular suppression was reduced in 43 % of participants and stereoacuity improved in 14 % of participants following treatment. Visual acuity improvement was greater with clinic than home-based treatment, while global motion improvement was greater in the strabismic amblyopic group. There was no effect of participant age. The Vivid Vision dichoptic treatment improved monocular and binocular measures in some but not all participants.