Purpose: To compare the Moria Model Two (M2) automated microkeratome with the head 90 (intended to create a 120-microm flap) to the head 130 (intended to create a 160-microm flap) in reoperations following previous photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK) in terms of accuracy, predictability, safety and complications of the procedure.
Methods: Eighty-five eyes of 70 consecutive patients received LASIK with the Moria M2 microkeratome. Nine previously PRK-operated eyes were reoperated with the head 90 and 37 eyes were reoperated with the head 130. Repeated LASIK was performed on 16 eyes with the head 90 and on 23 eyes with head the 130. Flap dimensions were measured and correlated to preoperative parameters.
Results: The average flap thickness in the previously PRK-operated eyes was 115.1 microm [range 82-137 microm, standard deviation (SD) 17.9] with the head 90 and 131.2 microm (range 105-171 microm, SD 19.8) with the head 130. In the previously LASIK-operated eyes, the mean flap thickness was 139.2 microm (range 92-182 microm, SD 23.8) with the head 90 and 141.9 microm (range 109-179 microm, SD 15.2) with the head 130. There were no free or incomplete flaps or flaps with buttonholes in the study. There was no statistically significant difference in postoperative uncorrected visual acuity (UCVA) between the groups.
Conclusion: In eyes with previous PRK or LASIK, LASIK reoperation offers a safe alternative for improving refractive outcomes. The Moria M2 head 90, especially in LASIK-operated eyes, does not cut thinner flaps compared to the head 130.