Risk factors for insufficient fixation of microkeratome during laser in situ keratomileusis

PURPOSE: To investigate the potential risk factors leading to insufficient fixation of a microkeratome during laser in situ keratomileusis (LASIK), especially in Asian eyes. METHODS: We performed a retrospective analysis of 1809 eyes of 972 patients that underwent LASIK. Profiles of patients (age, sex, past medical history, width of palpebral fissure, corneal power, and postoperative clinical course) whose operations were discontinued due to insufficient fixation were compared to all LASIK patients. RESULTS: Insufficient fixation was observed in 18 eyes of 16 patients. Those patients were significantly younger (26.1 +/- 5.5 yr) compared to all patients (32.3 +/- 8.6 yr). Mean keratometric power was 42.40 +/- 1.37 D in patients with insufficient fixation and 43.60 +/- 1.40 D in all patients (P<.001). Maximum width of palpebral fissure with eyes wide open was 0.96 +/- 0.20 mm in patients with insufficient fixation, and 1.10 +/- 0.19 mm in all patients (P=.0015). These patients subsequently underwent LASIK utilizing combinations of cooling, frequent corticosteroid instillation for several hours, and lateral canthotomy. CONCLUSION: Narrow palpebral fissures commonly found in Asian populations might be a risk factor for insufficient fixation of a microkeratome in LASIK, especially in young patients with flat corneas.