Abstract
Purpose :
While the clinical focus for amblyopia has been monocular patching to restore visual acuity of the amblyopic eye, recent evidence supports the primary role of binocular dysfunction in amblyopia. Binocularly discordant visual experience during early childhood results not only in a monocular visual acuity deficit, but can also affect both amblyopic and fellow eye motion perception. We determined the prevalence of fellow eye motion perception deficits, assessed associations with clinical and sensory factors, and explored the effectiveness of patching versus binocular treatment in alleviating fellow eye deficits.
Methods :
81 amblyopic children (6-12y; 0.2-1.5 logMAR) with strabismus (n=19), anisometropia (n=34), or both (n=28) participated, along with 19 age-similar controls. All amblyopic children had been treated with spectacles, patching, and/or binocular treatment but had residual amblyopia. Performance on a motion-defined form (MDF) task was evaluated in the context of a Star Wars game. The child was asked to indicate the orientation of a rectangular enemy spaceship defined by coherently moving dots surrounded by dots moving in the opposite direction. The proportion of coherently moving dots was progressively reduced to determine the coherence threshold. Sensory factors (visual acuity [VA], stereoacuity, Worth-4 dot [W4] fusion, suppression) were assessed at the same visit; clinical factors (age at diagnosis, initial VA, surgery, prior treatment) were obtained from medical records.
Results :
There were no significant differences in any of clinical factors between children in patching vs binocular treatment groups. Overall, MDF deficits were present in 19% of fellow eyes in treated amblyopic children. Fewer children had fellow eye MDF deficits following binocular treatment than after patching (10% vs 31%, p=0.02) and MDF deficits were less severe after binocular treatment than patching (p=0.013). Fellow eye MDF deficits correlated with stereoacuity (p=0.004), W4 fusion (p=0.005), and age at diagnosis (p=0.009), but not with amblyopic eye VA.
Conclusions :
Fellow eye motion perception deficits are common, affecting 1/3 of amblyopic children treated with patching, and likely reflect abnormalities in binocular cortical mechanisms resulting from discordant visual experience. Binocular amblyopia treatment, which is effective in improving visual acuity, may also provide a benefit for the fellow eye.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.