Stereoscopic visual acuity in types of ametropic amblyopia in children

To evaluate the presence of stereopsis in children with ametropic amblyopia, including hyperopia, myopia, and astigmatism.

A total of 205 children with the average age of 5.2 years were selected, including 65 cases of astigmatic amblyopia, 30 of myopic amblyopia, and 110 of hyperopic amblyopia. The near stereoacuity test (zero disparity stereoacuity, crossed disparity, and uncrossed disparity) and distance stereoacuity test by synoptophore with Yan's random-dot test in The Examination Chart of Stereoscopic Acuity were performed. Visual acuity was examined with the standard Snellen chart. Distance fusion was determined with the synoptophore. Correlations between amblyopia and stereopsis were performed with logistic procedure.

Differences between zero disparity stereoacuity of hyperopia, myopia, and astigmatism were statistically significant in children with mild and moderate amblyopia determined by the near stereoacuity test (P < .05). Individuals with hyperopia have better central stereopsis and macular stereopsis, whereas children with astigmatism have significantly decreased stereoacuity. No difference was identified between the three types in children with severe amblyopia (P > .05). Results of different degrees of amblyopia at distance and near were approximate. In amblyopic eyes, difference between hyperopia, myopia, and astigmatism, determined with synoptophore, was not significant (P > .05). The types and degrees of amblyopia were closely related with stereopsis (P < .001).

In mild and moderate amblyopic eyes, children with astigmatism had the worst stereoacuity. This group should pay more attention to visual stimulation training and stereopsis training.