AC/A Ratio Measured by Modified Gradient Method.
- Author:
Jong Bok LEE
1
;
Sang Gyun BUM
Author Information
1. Department of Ophthalmology, Yonsei University, College of Medicine, Seoul, Korea.
- Publication Type:Original Article
- MeSH:
Esotropia;
Exotropia;
Hand;
Humans;
Ocular Motility Disorders;
Reference Values;
Vision Disparity
- From:Journal of the Korean Ophthalmological Society
1987;28(4):799-804
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
A clinical study on the AC/A ratio with 125 normal persons was performed by modified gradient method. AC/A ratio is a convergence response of an individual to a unit stimulus of accommodation. Through many studies on the AC/A ratio, the normal range of the AC/A ratio was 3 delta/D ~ 5 delta/D. The AC/A ratio can be changed by some drugs. The AC/A ratio is high in divergence excessive exotropia, pseudodivergence exotropia and non-refractive accommodative esotropia; on the other hand, the AC/A ratio is low in convergence insufficiency exotropia. Methods for the determination of the AC/A ratio are heterophoria method, gradient method, fixation disparity method. This study was performed by modified gradient method due to easy application. The mean of the AC/A ratios in this study was 4.55 delta/D, and the AC/A ratios ranged from 0.5 delta/D to 9.6 delta/D. 95 percentile ranged from 3.01 delta/D to 6.09 delta/D. The AC/A ratio in this study seems not to be correlated with age, sex and interpupillary distance.
