Purchase this article with an account.
D. J. Pierre, M. R. Chalita, J. C. Ramos-Esteban, M. Xu, R. R. Krueger; Corneal Changes Following LASIK and Enhancement With Microkeratome and Femtosecond-Laser Flaps. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5362.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare changes in corneal flap and stromal bed thickness after primary LASIK procedure between flaps created by mechanical microkeratome versus femtosecond laser for myopic, hyperopic, or astigmatic ablations.
Retrospective review of 209 eyes after LASIK enhancement. Eyes were divided into mechanical and laser flap groups and further subdivided into myopic, hyperopic and astigmatic ablation subgroups. Central corneal thickness, preablation stromal bed thickness, and theoretical laser ablation depth were data collected from both primary and enhancement procedures to determine changes between procedures.
Table 1. Difference in Flap Thickness between Primary Procedure and Enhacnement and Table 2. Difference in Stromal Bed Thickness between Primary Procedure and Enhancement summarize pachymetric information for the Femtosecond and Mechanical groups as well as for myopic, hyperopic, and mixed astigmatic subgroups. Significant findings follow. In both laser and mechanical groups, flaps at time of enhancement were thicker following myopic ablation, the thickening being greater in mechanical flaps. Residual stromal beds were thinner after myopic ablation in both groups. Stromal beds were thicker after hyperopic ablation in both groups. The stromal bed was thicker following astigmatic ablations in the mechanical group, but unchanged in the femtosecond group.
There are differences in the way the cornea flap and stromal bed changes after primary LASIK procedures between flaps created by a femtosecond laser and a mechanical microkeratome. The greater increase in flap thickness following myopic LASIK may be due to epithelial hyperplasia, and is statistically more prominent in mechanical flaps. The fact that changes appear to be predictable in both myopic and hyperopic treatments could aid refractive surgeons when planning a primary LASIK procedure. Also, the two flap creation methods demonstrate similar magnitudes of stromal thinning after myopic ablations and thickening after hyperopic ablations.
This PDF is available to Subscribers Only