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Background: In recent years, it has been established that the suppression of the amblyopic eye by the fellow eye is the major cause of amblyopia. New behavioural therapies like dichoptic therapy attempt to reduce suppression in amblyopic adults who have passed the critical stage of visual cortex development. Anisometropic amblyopia has the highest prevalence of amblyopia, and managing this condition in adults may lead to improvement in the quality of life. Aim: The purpose of the review is to assess the impact of this novel treatment of amblyopia, with particular focus on using dichoptic therapy for anisometropic amblyopia in adults. Methods: A literature search was conducted on articles published in the last 20 years, and papers were sourced from databases such as Elsevier, Science Direct and PubMed using the reference manager Mendeley. (The search was performed from December 2017 to December 2018.) Results: Evidence from located studies in adults with anisometropic or mixed amblyopia managed with new behavioural treatments including dichoptic therapy showed some significant improvement in the best-corrected distance visual acuity, stereopsis and contrast sensitivity whilst improving or restoring optimal binocular vision. Conclusion: Adults with anisometropic and/or mixed amblyopia can benefit from dichoptic therapy with a unique approach to improve binocularity concurrently. The therapy represents a viable option for managing amblyopia in adults and can be administered as office-based or home-based treatment in a timely manner that could improve the quality of life for such patients.

Aim: We tested whether prism fusion range (PFR) could be improved by training and whether any improvement in PFR also led to improvement in stereo-acuity. Methods: The PFR and stereo-acuity thresholds of 15 participants with normal or corrected-to-normal vision were tested intially then at 1 week and 5 weeks. Eight of the participants, the experimental group, were instructed in training their base-in and base-out near prism fusion at home for 10 minutes twice each day for 1 week. Seven participants, the control group, were simply tested on three occasions without training. Results: For the experimental group after 1 week both near and distant PFR had significantly improved, by over 10∆ compared with the control group. Stereo-acuity had improved significantly but modestly by about 3 sec arc. However, 4 weeks later, during which no further training occurred, both PFR and stereo-acuity were no longer significantly different between the groups. Conclusions: Although in visually normal participants training of near PFR can lead to improvement in near and distant PFR and stereo-acuity, in the longer term no differences were found between the trained group and a control group who were untrained. These results emphasise the importance of including for comparison a non-treatment group in such studies.