To evaluate associated factors by comparing the patients with consecutive exotropia to the patients with orthophoria after undergoing surgery for infantile esotropia.

The study consisted of 50 patients who underwent bilateral medial rectus recession and attended follow-ups until eight years of age. The authors retrospectively investigated the clinical characteristics ofage at operation, duration between diagnosis and operation, the spherical equivalent of both eyes, the deviated angle at the first visit and immediately before the operation, the recession amount, and the total follow-up period.

During the mean follow-up period of 78.51±54.70 months, 13 patients (26%) had consecutive exotropia, 27 patients (54%) had orthophoria and 10 patients (20%) had remnant esotropia. As the result of comparing orthophoric patients to consecutive exotropic patients, there were no significant differences in the birth weights, the deviated angles at the first visit and immediately before the operation, the spherical equivalents of both eyes, the ages at operation, the recession amounts, and the durations between diagnosis and operation. However, in consecutive exotropia, inferior oblique muscle overaction was 46.5%, dissociated vertical deviation was 46.5% in orthophoric patients, inferior oblique muscle overaction was 19.24%, and dissociated vertical deviation was 8.7%.

A thorough follow-up is necessary when inferior oblique muscle overaction and dissociated vertical deviation occur after undergoing a bilateral medial rectus operation.