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A Ivarsen, T Moller-Pedersen; Characterization of Corneal Wound Repair at the LASIK Flap Edge . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4238.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Inadequate wound healing of the LASIK flap may be associated with severe complications including flap dislocation, epithelial ingrowth, and flap melting. The present study characterizes temporal changes in corneal wound repair at the LASIK flap edge. Methods: Fifteen rabbits received monocular LASIK and were evaluated during a six-month period using slit-lamp and in vivo confocal microscopy. Three corneas were vitally stained with DTAF to allow detection of newly deposited fibrotic tissue. At various timepoints, corneas were processed for histology and stained for nuclei, f-actin, ED-A fibronectin, and α-smooth muscle actin. Results: At day one, leukocytes migrated from the conjunctival vessels into the cornea. Near limbus, the leukocytes were often organised into long chains stretching towards the flap edge; suggestive of directional migration in preformed cavities. From day four, elongated fibroblasts (with a prominent f-actin expression) migrated from the periphery towards a circumferential band (250 µm wide), immediately peripheral to the flap edge. The lateral extension of this wound repair zone (WRZ) was sharply delimited by the incisional gap in the basement membrane. At three weeks, limited myofibroblast transformation occurred within the WRZ, and over time a 50 µm thick layer of new fibrotic matrix was deposited. Concurrently, the WRZ showed an increased organisation and a gradual decline in light reflectivity. Throughout the study, no major acellular zones were identified, and keratocytes within and below the flap remained quiescent. Conclusion: Post-LASIK wound repair is located to a narrow band peripheral to the flap edge. Only minimal fibrosis develops below the flap, which may explain the high proportion of flap-related LASIK complications.
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