Study on function of visual pathway among amblyopes through analysis of pupil size variance

Abstract

Objective Under different four illumination conditions,comparing the variance of pupil size between the amblyopia eyes and the contralateral normal eyes in monocular amblyopia children to analyze the variance in function of visual pathway of the amblyopia eyes. Methods 30 monocular amblyopia children were selected in random which is including 17 anisometropic amblyopia children,8 ametropia amblyopia children and 5 strabismic amblyopia children,in which of them,there 're 13 Moderate amblyopia and 17 mild amblyopia.The corrected vision of the amblyopia eyes in all of the subjects is 0.2-0.8,while their contralateral normal eyes is 0.9-1.2,Pupil size measured by digital camera means under different four illumination conditions -daylight,direct light reflexion,indirect light reflexion and dark illumination.Every subjects were required to focus on far E optotype and near E optotype respectively,then we compared the pupil size of amblyopia eyes with those of contralateral eyes.Results Under different four illumination conditions,when subjects focus on far and near E optotype,the pupil size of amblyopia eyes was larger than contralateral eyes(paired-samples t test,P<0.05).The pupil size of amblyopia eyes on direct light reflexion condition was larger than amblyopia eyes on indirect light reflexion condition,whatever they focus on at far or near;the pupil size of amblyopia eyes on indirect light reflexion condition was also larger than contralateral eyes on direct light reflexion condition,the pupil size of amblyopia eyes on direct light reflexion condition was also larger than contralateral eyes on indirect light reflexion condition(paired-samples t test,P<0.05).Conclusion The results revealed characteristic suggesting a malfunction of the retina,the visual cortex in amblyopic eyes,besides,the malfunction of E-W nucleus is probably the main reason for the abnormal pupil size in amblyopic eyes.This clinical finding infers that impairment exits in rentia,visual pathway and also visual cortex during the development of the amblyopia. Key words: Amblyopia; Pupil size; Pupillary light reflex