Simultaneous LASIK on both Stromal Surface and Flap Undersurface for High Myopia with Insufficient Corneal Bed

Hong, Hyo Chang; Kim, Jae Ho

Abstract

PURPOSE
To develop a newly modified technique, which is simultaneous laser in situ keratomileusis on both corneal flap undersurface (LASIK-Flap) and the corneal stromal surface, in eyes with insufficient corneal bed of high myopia and thin cornea. METHODS: We performed simultaneous laser in situ keratomileusis on both corneal flap undersurface (LASIK-Flap) and the corneal stromal surface in 38 eyes of 22 patients with high myopia (ranged from SE -4.00D to -14.25D)and corneal thickness (ranged from 435 to 570 micro meter) . In these eyes, all procedures of 130 ~ 160 micro meter thickness of the flap preparation with hinge were successfully made with a use of the Moria M2 microkeratome. The ablation on both the corneal surface and the flap undersurface using VISX star S4 with active track was performed with a plan of postoperative residual corneal stromal bed >250micro meter. We evaluated the changes of visual acuity, refractive error, pachymetry, corneal topography and mesotest for at least 6 months after surgery. Preservation of normal wet state on the flap in very important in procedures. RESULTS: Mean SE was -9.32 +/- 2.75D and mean corneal thickness was 513.37 +/- 36.96 micro meter ranged from 435 micro meter to 570 micro meter before LASIK. Ablation depth of flap undersurface was 48.87 +/- 26.67 micro meter ranged from 6 micro meter to 100 micro meter, and post LASIK spherical equivalent was +0.02 +/- 0.62D (ranged +2.50 ~ -1.50D). No vision concerned complication was found. Follow-up was ranged from 1week to 6 months. CONCLUSIONS: LASIK-flap procedure has an advantage in eyes with insufficient corneal thickness in high myopia.