AIM: To evaluate actual versus expected laser in situ keratomileusis (LASIK) flap thickness using the Moria M2,130 microkeratome head.
METHODS: 50 eyes of 25 patients scheduled for LASIK surgery for myopia where enrolled in this study. Patients were prepared for surgery. On the day of surgery they were admitted to the LASIK room where the lids were sterilized and draped. A suction lid speculum was applied to one eye after instilling one drop of Benox into the conjunctival sac, the eye was then washed with balanced salt solution BSS and the suction of the lid speculum activated to assure there was no excess BSS in the conjunctival sac then a final preoperative ultrasonic central corneal pachymetry reading using the sterile probe of the Tomey AL-2000 pachymer was recorded. The suction ring of the Moria M2 mikroketatome was centered on the cornea and immediately after the lasik flap was fashioned and the suction ring removed the flap was elevated then an intra operative central stromal bed pachmetry reading was recorded using the sterile Tomey AL-2000 pachymer probe. The actual flap thickness was calculated by subtracting the intra operative central stromal thickness from the preoperative central corneal thickness.
SETTING: Out patient Lasik center in the period from January 2004 till beginning of February 2004.
RESULTS: The mean actual flap thickness created by the Moria M2 130 head microkeratome for the first cut was 153.8 + 17 (range 120µm – 188µm) and for the second cut 148.4 + 15.82 (range 118- 185). The mean difference in flap thickness between the first and second cut was 4.4µm + 1.7µm with the tendency of the second flap to be slightly thinner than the first. This difference was found to be statistically insignificant (P>0.05, paired t test). The mean difference between the actual and expected flap thickness was 9.9µm + 1.7 and this was found to be statistically significant ( P |
