Abstract
Purpose :
Previous studies have reported a naso-temporal asymmetry for global motion perception, favoring nasalward motion, is present in children and adults with a history of unilateral enucleation. Deprivation amblyopia from unilateral cataract or other forms of unilateral visual impairment results in a less complete form of monocular deprivation. We investigated whether this directional asymmetry is also present in the fellow eye of children with deprivation amblyopia.
Methods :
25 children (10.33 + 2.44 years) with deprivation amblyopia (VA: 0.5 to 1.6 logMAR) from a history of monocular visual deprivation and 30 age-matched controls (9.85 + 3.68 years) participated in this study. Global motion perception for horizontal translation motion was measured for the fellow eye in the deprivation amblyopia group and in a random eye of the control group. Motion coherence thresholds (MCT) for nasalward and temporalward random-dot-kinematograms were measured using interleaved 2-down 1-up staircases. LogMAR visual acuity was measured by age-appropriate clinical tests.
Results :
Overall, the deprivation amblyopia group exhibited a robust naso-temporal asymmetry in favor of nasalward motion (mean nasal MCT: 10.5 ± 6% vs mean temporal MCT: 17 ± 10.5%, t24 = 4.39, p < 0.001). No such asymmetry was observed in the control participants (mean nasal MCT: 13.8 ± 6.8% vs. mean temporal MCT: 13.6 ± 6.6%, t29 = -0.23, p = 0.820). The ratio of temporalward/nasalward MCT asymmetry was significantly higher (t52 = 4.04, p < 0.001) in the deprivation amblyopia group (ratio: 1.86 ± 1.10) compared with the control group (ratio: 0.99 ± 0.34). Furthermore, a linear regression revealed that intervention age, age at testing, and gender did not significantly predict the extent of motion asymmetry in the deprivation amblyopia group.
Conclusions :
Naso-temporal asymmetries for global motion perception are present in the fellow eye of children with monocular deprivation. This asymmetry highlights the importance of binocular visual input for the normal development of extrastriate areas such as V5/MT+ that support motion integration. Our results are consistent with the previous reports of similar directional asymmetry in motion perception in monocular enucleation.
This is a 2021 ARVO Annual Meeting abstract.