Decentration after refractive surgery

PURPOSE: To examine factors useful in evaluation of suspect decentration af ter refractive surgery, METHODS: We evaluated 148 cases (eyes) referred to us for recentering proce dures by review of information obtainable by evaluation of pupil position, corneal topography, and corneal curvature gradient. RESULTS: Only a minority of eyes (n=5, 3.4%) were truly decentered; in the remaining majority a high dioptric gradient with consequent focal scarring was present (n=107, 72.3%). In 28 eyes (18.9%), a drifting of the eye durin g treatment was responsible, and in eight eyes (5.4%), a central island was observed. CONCLUSIONS: Proper corneal topographical diagnosis reduces the risk of imp roperly suspecting decentration, and for most cases, smoothing of the centr al cornea is a simple and efficacious solution. Recommendations for the pre vention of decentration include proper patient positioning, special care in treating high myopes, preoperative check of pupil displacement nasally, ev aluation of preoperative map with detection of high temporal curvature grad ient, and use of the cross-cylinder technique in the treatment of astigmati sm.