Corneal healing following laser refractive keratectomy
G. L. Goodman, S. L. Trokel, W. J. Stark, C. R. Munnerlyn and W. R. Green
Wilmer Institute, Johns Hopkins Hospital, Baltimore, MD 21205.
A 193-nm excimer laser system was used to ablate 4.5-mm optically contoured
zones in the corneal stroma of rabbits to achieve optical flattening of 2,
4, 8, and 16 diopters. We studied the effect of edge profile and wound
depth on reepithelialization and stromal remodeling using dichlorotriazinyl
aminofluorescein, a vital dye that covalently binds to the stromal bed and
delineates the boundaries of new collagen synthesis. All the corneas
reepithelialized; no subsequent recurrent erosions occurred. All seven
corneas that received an ablation of less than 50 microns were clear
centrally at 8 weeks. At an ablation depth of approximately 100 microns,
opacification and scarring were observed biomicroscopically and
histopathologically in two specimens. No evidence of new collagen formation
or epithelial hyperplasia was found in any of the seven corneas that
remained clear. Stromal remodeling was observed in the two corneas that
exhibited scarring.
