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MS Muallem, SH Yoo, AC O Romano, WW Culbertson; Flap Thickness in LASIK Procedures Utilizing the Moria M2 Microkeratome . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2081.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine the predictability of flap thickness in LASIK procedures utilizing the Moria M2 microkeratome and to identify factors that may be related to variations in flap thickness. Methods: In the preliminary study, 59 patients underwent same day bilateral LASIK utilizing the Moria M2 microkeratome to create the corneal flap. The right eye was always treated first. The same suction ring, stop, microkeratome head (110 or 130) and blade were used in fellow eyes. In some eyes, the adaptor for slow movement of the microkeratome head was used. All flap hinges were at the 12:00 o'clock location. Patients with difficulty obtaining satisfactory suction, more than 60 seconds suction time, or eccentric flaps were excluded. The central corneal and residual corneal bed thicknesses were measured with pachymetry just before and immediately after creating the flap, respectively. The difference between the two measurements yielded the flap thickness. Other collected data included age, keratometry, corneal diameter, and preoperative spherical equivalent. The predictability of the flap thickness in the right eye to the flap thickness in the left eye was investigated. Results: Utilizing the 110 head, the mean flap thickness in the right eye was 157.7±21.2µ and 132.8±26.8µ (p=0.002) with and without using the adaptor for slow movement, respectively. In the left eye, the corresponding means were 148.8±23.1µ and 131.4±19.8µ (p=0.011). When utilizing the same speed of the microkeratome head in fellow eyes, there was no statistically significant difference in flap thickness between them (p=0.3). In patients with the adaptor for slow movement utilized only in one eye, the mean flap thickness was significantly different between fellow eyes only when the adaptor was used in the right eye (p=0.003). Utilizing the 130 head without the adaptor for slow movement, there was no statistically significant difference between flap thicknesses in fellow eyes. Multivariate analysis confirmed that fast translational speed of the microkeratome head produced thinner flaps. The flap thickness in the right eye was not found to be a strong predictor of the flap thickness in the left eye. No other factors were identified that affected the flap thickness. Conclusion: The preliminary results of our ongoing study show that increasing the translational speed of the Moria M2 microkeratome head produces thinner flaps. Flap thickness was not strongly correlated with keratometry readings, corneal diameter, corneal thickness, preoperative spherical equivalent or age. No predictability of the flap thickness between fellow eyes was identified.
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