Preoperative Factors related to Corneal Flap Thickness in LASIK using Microkeratome

ABSTRACT

PURPOSE: To identify factors that may be related to variations in corneal flap thickness in LASIK using the Moria M2 microkeratome. METHODS: The charts of patients having LASIK based on steep keratometry nomogram using Moria M2 microkeratome (head 110 micrometer) and excimer laser (VISX STAR S2, USA) in our department of ophthalmology from March, 2003, to May 2005, were reviewed retrospectively. A total of 195 eyes were enrolled in the investigation. We analyzed relationship between corneal flap thickness and preoperative factors including central corneal thickness, steep keratometer, corneal diameter, suction ring using multiple regression analysis. RESULTS: Mean corneal flap thickness was 119.37+/-21.21 micrometer. There was a statistically significant positive correlation between flap thickness and central corneal thickness (p<0.05). No correlation was found between flap thickness and other preoperative factors including steep keratometer, corneal diameter and suction ring. CONCLUSIONS: Mean corneal flap thickness using the Moria M2 110 micrometer head was 119.37+/-21.21 micrometer, little thicker than our expectation. When surgery is performed based on steep keratometry nomogram using Moria M2 microkeratome, if intraoperative factors are excluded, there is a trend toward thicker flap thickness with thicker central corneal thickness, whereas steep keratometer, corneal diameter or suction ring have no influence on flap thickness.