Influence of flap thickness on visual and refractive outcomes after laser in situ keratomileusis performed with a mechanical keratome

Abstract

To study the effect of flap thickness on visual acuity and refractive outcomes after laser in situ keratomileusis (LASIK) using 2 blade types with a mechanical microkeratome. Emory Vision, Atlanta, Georgia, USA. This retrospective analysis was of LASIK cases performed between January 2005 and June 2006 using an Amadeus I microkeratome and an ML7090 CLB blade (blade A) or a Surepass blade (blade B). Outcomes analyzed included flap thickness, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), the enhancement rate, and surgical complications 3 months postoperatively. Two hundred sixty-three eyes of 153 patients were analyzed; blade A was used in 158 eyes and blade B, in 105 eyes. The mean flap thickness was significantly thinner with blade A than with blade B (107 microm +/- 12 [SD] versus 130 +/- 20 microm) (P<.0001). There was no overall correlation with either blade between flap thickness and UDVA, CDVA, or MRSE (all r<0.2). At 3 months, there was no statistically significant difference in UDVA, CDVA, or MRSE between the 2 blade groups at 3 months (all P > .10), and there was no difference in the complication rates. Flap thickness did not affect visual or refractive outcomes with a mechanical microkeratome with either blade type.