Clinical Features of Type III Acute Acquired Concomitant Esotropia and the Effect of Prism Correction

Objective: To analyze the clinical features of acute acquired c oncomitant esotropia (AACE) type III and the effect of prism correction, including three-stage visual function, stability and the degree of satisfaction. Methods: This was a self-control study. Patients with AACE (III) were examined for strabismus with a von Graefe prism, Maddox rod and synoptophore. The fusion range was measured with a synoptophore, and a prism was prescribed. The changes in values before and after wearing the prism were analyzed, and a satisfaction survey was done. The data were analyzed by a paired t test. The follow-up period ranged from 2 months to 2 years (0.7±0.5 years). Results: The degree of distance and near strabismus with the von Graefe prism was 16.9△±7.0△ and 15.1△±7.5△; with Maddox rod it was 22.6△±8.5△, 16.3△±9.0△; and the degree of distance strabismus with a synoptophore was 18.0△±8.2△. The fusion range with synoptophore was 25.4°±8.8°. The prism preschiption was 6.4△±3.0△. The comparison of distance strabismus and near strabismus with the von Graefe prism separation was no significant difference before and after wearing the prism (t=0.266, P=0.792 and t=0.731, P=0.471). The comparison of distance strabismus and near strabismus with Maddox rod was no significant difference before and after wearing the prism (t=-0.040, P=0.969 and t=-0.587, P=0.562). The comparison of distance strabismus with the synoptophore was t=-0.523, P=0.606 before and after wearing the prism. There was no significant difference in the fusion range (t=-1.210, P=0.237) or the strength of the prescription (t=0.000, P=1.000). There was no difference in stereopsis before and after wearing the prism. After wearing the prism, diplopia disappeared and the subjective evaluation of the effect of the prism was satisfactory for 11% and very satisfactory for 89%. Conclusions: AACE type III has the clinical features of a wide onset age range, large strabismus degree, greater distant strabismus degree than near strabismus degree, fusion function and potential stereopsis function. Prism correction is a good method that can eliminate diplopia, and will not affect the degree of strabismus, fusion range, or stereopsis. Key words: acute acquired concomitant esotropia; diplopia; strabismus; prism