Nonaccommodative factors of refractive accommodative esotropia.

The clinical characteristics of 45 cases of refractive accommodative esotropia were compared with 31 cases of the control group who remained orthotropic in the presence of uncorrected same degree of hypermetropia. In addition to the general ophthalmologic and orthoptic examinations, the accommodative convergence/accommodation (AC/A) ratio, fusional vergences and random dot stereopsis were investigated. The hypermetropic patients without esotropia were found to have a lower AC/A ratio and normal fusional function, while in cases with refractive accommodative esotropia, their AC/A ratios were normal and their fusional functions were decreased, especially significant being the divergent fusional function. In both groups, their stereopsis was defective or absent. It is suggested that esotropia be not simply caused by excessive accommodation due to uncorrected hypermetropia, and the range of divergent fusional function and the level of AC/A ratio be the two factors which determine the causation of esotropia in cases with uncorrected hypermetropia.