Abstract
Purpose: :
To investigate how the amblyopic, the fellow, and both eyes could perform differently regarding reaction time (RT) and visual sensitivity in anisometropic amblyopes with or without microtropia.
Methods: :
Subjects were 5 anisometropic amblyopes without microtropia (age ranged, 6.3-8.1 years) and 10 anisometropic amblyopes with microtropia (age ranged, 6.4-9.7 years) who had completed occlusion therapy and could be examined for RT. The amblyopic eyes without microtropia had the post-treatment visual acuity (VA) of 1.0 (0 log MAR) or better while the post-treatment VA of the amblyopic eyes with microtropia ranged 0.5-0.9 (0.30-0.05 log MAR). RT was measured by the Octopus 900 perimeter with a GKP program and visual sensitivity was evaluated using a white-spot target of 0.431° visual angle. The test locations were arranged at 4 positions on the meridians of 45°, 135°, 225° and 315°. Targets were moved outward along the four meridians with a velocity of 3.0 deg/s.
Results: :
The amblyopic eye had significantly lower visual sensitivity than the fellow eye in both groups (p<0.01). In the microtropes, no significant difference in visual sensitivity was seen between the fellow eye and both eyes. In the non-microtropes, binocular visual sensitivity was higher in the fellow eye (p<0.05) but it did not exceed the expected probability summation. The RTs of the amblyopic eye, fellow eye, and both eyes did not significantly differ in the non-microtropes. In the microtropes, the amblyopic eye had significantly longer RT than the fellow eye (p<0.01), while the RT difference between the fellow eye and both eyes was not significant. While RT for both eyes was longer than RT for the fellow eye in 4 (40%) of the 10 microtropes, this was not observed in any of the non-microtropes.
Conclusions: :
Our results showed that in cases of anisometropic amblyopia with microtropia, not only visual sensitivity but also RT were influenced by the disease even after amblyopia therapy. In addition, the influence of amblyopia on RT could depend on the type of amblyopia.
Keywords: amblyopia • binocular vision/stereopsis • visual fields