Drift of ocular alignment following strabismus surgery. Part 1: using fixed scleral sutures

To evaluate the postoperative alignment drift following traditional strabismus surgery utilizing direct attachment of muscle to sclera.

The ocular alignment drift (change from the first postoperative week) of 106 patients who underwent scleral fixation strabismus surgery at age 0.5 to 35 years with 5 years' maximal follow-up was analysed.

There was a mean undercorrection drift of 4.6 (SD 8.9) prism dioptres (PD) at distance fixation (p = 0.025) and 3.4 (7.6) PD at near (p = 0.053) for all subjects, and 11.3 (8.6) PD distance (p = 0.008) and 10.6 (6.0) PD near (p = 0.016) for exotropic patients. Recession surgery produced an undercorrection drift of 5.3 (8.8) PD (p = 0.021) at distance fixation. Esotropic patients and those undergoing unilateral recession/resection surgery had no significant drift. Patients overcorrected at the 1-week postoperative visit later developed an undercorrection drift at distance (10.3 (7.9) PD, p = 0.002) and near fixation (5.5 (9.2) PD at 36 months, p = 0.041), while undercorrected patients showed no significant drift and largely stayed undercorrected.

Fixed scleral-suture strabismus surgery generally produces a postoperative undercorrection drift, especially following recession surgery, exotropia or overcorrection at the first postoperative week.