Changes in astigmatism after ptosis surgery measured by corneal topography.

A computerized topographic analysis system (EyeSys [EyeSys Technologies, Houston, TX, U.S.A.]) was used to evaluate corneal astigmatic changes (central corneal power and astigmatic axis) after blepharoptosis surgery on 29 eyelids (22 patients). Fifteen nonoperated eyelids of study patients undergoing unilateral ptosis repair were used as controls. All patients were evaluated preoperatively and again 6 weeks after surgery. Fifteen operated eyelids and five controls were also examined 12 months after surgery to evaluate the stability of these measurements. In 72.4% of operated eyes, corneal topography demonstrated increased with-the-rule astigmatism 6 weeks after surgery, 13.8% of surgical eyes showed increasing against-the-rule astigmatism, and in 13.8%, no change was noted from preoperative measurements. None of the 15 control eyes demonstrated any change in corneal astigmatic axis or significant change in central corneal power. By 12 months after surgery, all of the operated eyes showed a regression toward the amount and pattern of preoperative astigmatism. Only two of 15 eyes maintained a difference of > 0.3 D of central corneal power greater than their preoperative measurement at 1 year. These data suggest that corneal topography may be altered by changes in eyelid position, although the changes appear to be temporary in most patients.