ABSTRACT
Binocular function is not easy to obtain after strabismus surgery in adults with longstanding strabismus. In this study, postoperative binocular function was evaluated in 60 adults with longstanding horizontal strabismus. The subjects were eighteen years older and had developed strabismus before the age of eight. They were composed of 15 esotropes and 45exotropes without history of strabismus surgery. Pre-and postoperative stereopsis was assessed with Titmus-fly and Randot stereopsis tests. Visual acuity of the deviating eye, duration of deviation, angle of deviation, and status of stereopsis were compared according to the type of deviation. Stereopsis was shown in 20.0% of esotropes and 71.1% of exotropes before surgery. After surgery, only 46.7% of esotropes showed stereopsis in contrast with 91.1% of exotropes. In cases with congenital origin, 22.2% of esotropes and 83.3% of exotropes had stereopsis, while in those of acquired origin, 83.3%, and 92.3%, respectively. This study shows that stereopsis of good quality can be obtained and improved after surgery in adlts with longstanding horizontal strabismus except congenital esotropes. Higher gain of good postoperative stereopsis was related to better visual acuity of the deviating eye and shorter duration of deviation.