Corneal cell response after flap creation using a mechanical microkeratome or a 200 kHz femtosecond laser

Abstract

Purpose: To compare the inflammatory cell response within the corneal flap interface created by a mechanical microkeratome and a femtosecond laser.

Setting: Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.

Design: Experimental in vitro study.

Methods: Corneoscleral buttons of 12 enucleated human eyes not suitable for transplantation were put into organ culture. Corneal flaps were created using a 200 kHz femtosecond laser (Visumax) (femtosecond group) or a mechanical microkeratome (Amadeus) (microkeratome group). Flaps were not lifted after treatment. In 2 corneas, no treatment was performed (control group). Corneas were kept in organ culture for 12 hours thereafter. To evaluate cell-mediated immune reaction, immunofluorescent staining for leucocytes (cluster of differentiation 45) and specifically for dendritic cells (human leukocyte antigen-DR) was performed in every group. A terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was used to determine apoptosis reaction.

Results: The ratio of dendritic cells in the femtosecond group compared with the microkeratome group was 1.2 (P=.02), the ratio of leucocytes was 1.4 (P=.06), and the ratio of apoptotic cells was 1.0 (P=.59). There was no marked significant difference in the distribution of inflammatory cell reaction. The control group showed neither specific inflammatory reaction nor apoptosis.

Conclusion: This in vitro series of human corneas showed similar inflammatory tissue reaction after femtosecond laser-assisted and microkeratome-assisted flap creation (P<.05).

Financial disclosure: No author has a financial or proprietary interest in any material or method mentioned.