In:
Journal of Refractive Surgery, SLACK, Inc., Vol. 7, No. 3 ( 1991-05), p. 214-222
Abstract:
ABSTRACT: With an ArF excimer laser (193 nm, 750 mJ/cm p 2 , 20 Hz) and a special slit-mask system, perforating and non-perforating linear keratectomies were performed in 55 rabbit corneas with a follow-up from 1 hour to 6 months. Varying the pulse number according io ablation rate (0.8 µ???/pulse) and corneal thickness, four linear radial excisions (3 mm length, 70 µp? width) of increasing depth (70%, 80%, 90%, 100% perforation) were produced. The corneas were processed for light microscopy, scanning and transmission electron microscopy, and vital staining of the endothelium. Except for mild cell contact alterations and discrete single cell damage in the 90% deep excisions, no endothelial damage could be detected after non-perforating keratectomies. Minute ( 〈 20 µm and small (20 to 100 µmmaximal diameter) perforations induced cell enlargement, formation of pseudopodia, rosette-like figures, multi-nucleated giant cells, and ultimately uniform reformation of the cell pattern (1 hour to 7 days postoperatively). Larger excimer laser defects of Descemet's membrane ( 〉 100 µt?) were overgrown by dedifferentiated endothelial cells producing a new PAS-positive basement membrane. Vital staining revealed the complete and stable reorganization of the endothelium over these lesions within 6 months. Our observations are similar to those reported on the endothelial repair process following other surgical manipulations (knife incisions, direct Nd:YAG-laser trauma) and support the applicability of excimer lasers for corneal trephination in patients. Refract Corneal Surg 1991;7:214-222.)
Type of Medium:
Online Resource
ISSN:
1081-597X
DOI:
10.3928/1081-597X-19910501-06
Language:
English
Publisher:
SLACK, Inc.
Publication Date:
1991
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