Corneal wound healing in monkeys after repeated excimer laser photorefractive keratectomy
K. D. Hanna, Y. M. Pouliquen, G. O. Waring 3rd, M. Savoldelli, F. Fantes and K. P. Thompson
Department of Ophthalmology, Emory University, Atlanta, Ga.
Five rhesus monkey eyes underwent repeated argon fluoride (193 nm) excimer
laser myopic photorefractive keratectomy 3 months following an initial
ablation that had produced mild subepithelial haze. At 3 months all eyes
had development of a dense subepithelial opacity and a thickened epithelium
(12 cells, 80 microns) with vacuolization of basal cells, fragmented
basement membrane, and a layer of subepithelial fibrosis containing
activated fibroblasts. By 6 months the opacity was clearing; epithelium was
thinner (50 microns); subepithelial fibrosis was more lamellar. By 15
months only mild haze persisted clinically; epithelium was 30 microns
thick, with persistent basal vacuolization and focal basement membrane
disruption; subepithelial fibrous tissue was more organized. Early repeated
excimer laser ablation of the monkey cornea apparently induces vigorous
stromal wound healing. Use of shallower ablations, corticosteroids, or a
longer delay between ablations may be necessary for repeated laser surgery
to be practical clinically.
