Abstract
Purpose :
Researchers are developing binocular therapies in the treatment for amblyopia. Some products are now used in clinical practice. Vivid Vision® is a virtual reality system allowing for dichoptic training. Prior research has shown success with dichoptic treatments using image contrast adjustments (Li et al, 2013). In this study, we test our hypothesis that low-pass filtering (“blur”) and decreased luminance (“occlusion”) in the fellow eye image may benefit amblyopic patients with dichoptic training. We also investigate pre- and post-treatment thresholds for motion-defined form, global motion, and stereoscopic depth order discrimination in a subset of patients.
Methods :
Vivid Vision® was offered to patients if patching was unsuccessful due to poor compliance, reduced efficacy, or regression. 30 min sessions were conducted once weekly for 8 weeks. Equal amounts of “blur” and “occlusion” were applied to the fellow eye image of the dichoptic stimuli to find the minimum level required for patients to perform tasks with 70-80% accuracy throughout each session. Adjustments for ocular misalignments were made to optimize binocularity and eliminate diplopia. All patients including those who were stereodeficient on clinical tests at the start of treatment were able to perform the tasks with these modifications. No adjustment was made to image contrast.
Results :
34 patients were treated. Age range was 3 to 69 yrs: <11yrs (n=18); >11yrs (n=16). Improvement in VA for the amblyopic eye was statistically significant (p<0.0001). This finding was replicated when grouped by age: <11 yrs, >11 years; and etiology: anisometropic (n=25), combined aniso-strabismic/strabismic (n=9). Pre- and post-treatment stereoacuity improved in subjects that were not stereodeficient (n=15) at the start of treatment (p<0.05). Change in fellow eye VA was not significant (p=0.06). The effect of binocular treatment on the laboratory tasks of motion and depth perception was inconclusive.
Conclusions :
Our independent assessment on the clinical efficacy of Vivid Vision® confirms favourable outcomes. Even patients who are unable to pass clinical tests for stereopsis show benefit. “Blur” and “occlusion” introduced to the fellow eye may tap into binocular mechanisms that are less dependent on fine spatial tuning and which may be more resistant to amblyogenic factors due to earlier development.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.