gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

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Reduced keratocyte loss after laser epithelial keratomileusis (LASEK) in comparison to photorefractive keratectomy (PRK) in rabbits

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  • corresponding author R. Darawsha - Department of Ophthalmology, University Hospital Essen, Essen
  • T. Laube - Department of Ophthalmology, University Hospital Essen, Essen
  • C. Theiss - Department of Cytology, University of Bochum, Bochum
  • C. Brockmann - Department of Ophthalmology, University Hospital Essen, Essen
  • K.-P. Steuhl - Department of Ophthalmology, University Hospital Essen, Essen
  • D. Meller - Department of Ophthalmology, University Hospital Essen, Essen

Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogSO.04.03

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dog2004/04dog443.shtml

Published: September 22, 2004

© 2004 Darawsha et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective

To compare corneal wound healing with special regard to keratocyte loss and transformation of myofibroblasts in corneal stroma after LASEK and conventional PRK in rabbits.

Methods

LASEK and PRK were performed in rabbits and studied after 8 hours, 1, 3, and 14 days (each group n=2-4). In all eyes, corneal epithelium was pretreated with 30% ethanol for 3.5 min. In the PRK group, the whole epithelium was removed, but in the LASEK group an epithelial flap was created and repositioned after photoablation to adhere to the underlying stromal bed. Excimer photoablation was performed unilaterally with a 6.0 mm ablation zone and 106 μm depth equivalent to -9.0 dpt using the SUMMIT APEX PLUS laser with PRK mode. Keratocyte loss was analyzed using a DNA fragmentation detecting TUNEL assay. TUNEL positive keratocytes were counted in 4 different high power fields. A monoclonal antibody directed against α-smooth muscle actin which has been found in migrating myofibroblasts was applied for further analysis.

Results

8 hours after LASEK, eyes showed minor epithelial defects, whereas PRK treated eyes developed a distinct wouly located in the anterior corneal stroma were noted 8 and 24 hours after PRK which diminished distinctively after 3 days. LASEK treated eyes revealed significant less TUNEL positive keratocytes at the early postoperative time points and showed a delayed transient increase of TUNEL positive cells 3 days after laser photoablation. At 14 days, the number of TUNEL positive keratocytes decreased in both surgical groups and LASEK treated eyes revealed significantly less α-SMA positive myofibroblasts than PRK treated eyes.

Conclusions

LASEK does induce significantly less keratocyte loss and a reduced myofibroblast transformation than PRK and supports thereby wound healing in the acute phase after laser photoablation. LASEK might offer the possibility to treat higher myopia with reduced risk of developing complications as known to occur in PRK.