PURPOSE: To determine the drift variations of the postoperative alignment in patients who underwent strabismus surgery and to identify possible risk factors associated with such occurrence. PATIENTS AND METHODS: We reviewed the variations in postoperative alignment drift of 819 patients who underwent rectus muscle surgery from January, 1995 to December, 2005 at the Hospital de Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo. The patients were divided into four groups according to the type of deviation (alternating esotropia, monocular esotropia, alternating exotropia and monocular exotropia). Changes in eye positioning were quantified in each group. RESULTS: The prevalence of variations in the postoperative angle (considering variations more than 10 ∆) among the total of studied patients was 33.5% (274 patients). In those patients, a higher frequency was found in the exotropic direction (178 patients or 65.0%) than in the esotropic direction (96 patients or 35,0%), and this difference was statistically significant (chi-square test; p<0.001). CONCLUSIONS: Eye positioning instability can occur over time in patients who underwent strabismus surgery. This incident reinforces the need for the development of alternative therapies in order to provide greater stability to the oculomotor system in the follow-up of strabismus surgery.
Strabismus; Esotropia; Exotropia; Oculomotor muscles; Strabismus; Ocular motility disorders; Postoperative period
