Corneal flap thickness with the Moria M2™ microkeratome and Med‐Logics calibrated LASIK blades

Purpose: This study aimed to compare and study potential factors that affect the accuracy of corneal flap thickness created in laser‐assisted in situ keratomileusis (LASIK) using the Moria model 2 (M2?) head 130 microkeratome with the Med‐Logics calibrated LASIK blades Minus 20 (ML –20) and Minus 30 (ML –30). Methods: Corneal thickness in 200 (164 myopic and 36 hyperopic) eyes (100 patients) was measured by ultrasonic pachymetry preoperatively and intraoperatively after flap cutting. A total of 100 eyes were treated with the ML –20 and 100 with the ML –30. The right eye was operated before the left eye in each patient, using the same blade. In an additional group of 40 eyes, the left eye was operated first. Results: Mean corneal flap thickness using the ML –20 blade for an intended flap thickness of 140 μm was 129.1 μm (standard deviation [SD] 15.6, range 104–165 μm) in right eyes and 111.5 μm (SD 14.5, range 78–144 μm) in left eyes. Mean corneal flap thickness using the ML –30 blade for an intended flap thickness of 130 μm was 127.1 μm (SD 16.6, range 90–168 μm) in right eyes and 109.9 μm (SD 16.8, range 72–149 μm) in left eyes. Conclusions: Both microkeratome blade types cut thinner flaps than were intended. There was substantial variation in flap thickness. The first flap to be cut with a particular blade was considerably thicker than the second flap cut with the same blade. Based on these data, we recommend the use of disposable single‐use microkeratomes rather than these ML blades.