To evaluate clinical features and binocular function of long-standing intermittent exotropia detected for the first time in patients older than 16 years of age.

We retrospectively evaluated adult exotropic patients older than 16 years of age who were first diagnosed between March 2001 and February 2010. A total of 73 patients with exotropia who had not undergone ophthalmologic management for at least 10 years were included in the present study.

The mean age was 29.47 ± 12.13 years and 42 (57.5%) patients were male. The mean angle of deviation was 40.68 ± 17.75 prism diopter (PD); 46.58% of patients were between 30 to 50 PD and 26% were over 55 PD. Out Of 64 the intermittent exotropic patients, 17 patients had poor fusion at distance. Abnormal findings in binocular function such as poor stereoacuity, suppression at distance, reduced binocular visual acuity at distance, diplopia, panoramic vision, anomalous retinal correspondence, and accommodative spasms were observed. All 20 patients received surgery. Postoperatively, 59.90% of the patients showed improvement in near stereoacuity, and 78.57% improved in suppression at distance.

According to the present study, exotropia may cause subjective and objective deteriorations in motor/sensory function without appropriate medical or surgical intervention during childhood. In addition, the potential for improvement in binocular function after surgery was demonstrated even in adults. Therefore, we recommend surgical treatment for untreated, long-standing exotropia in adults.