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J Refract Surg. 1995 Nov-Dec;11(6):460-7.

Effect of corticosteroids on rabbits corneal keratocytes after photorefractive keratectomy.

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  • 1University of Houston, College of Optometry 77204-6052, USA.



To determine the corticosteroid effect on the activity and repopulation of keratocytes after photorefractive keratectomy (PRK).


A 193-nm excimer laser (VISX Twenty/Twenty) created a central ablation depth of 22 microns (diameter:5 nm) on 22 corneas of 16 albino rabbits. Two ablated eyes were examined 6 hours following PRK. Twelve eyes received no postoperative corticosteroids and eight were treated with topical fluoromethalone for 3 months. Corneas were examined 1, 3, 6, and 12 months after PRK by immunofluorescence and transmission electron microscopy.


Corticosteroids reduced haze (p=0.02), but all corneas (treated or untreated) cleared 6 months after PRK. Keratocytes were absent from the anterior 100 microns of the stroma 6 hours after PRK. However, the number and activity of keratocytes were significantly greater in this area in untreated corneas at 1 month and then gradually decreased. By 6 and 12 months, the number of keratocytes approached controls. Treated corneas had fewer keratocytes than either controls or untreated eyes (p<0.01) and by 3 months, a subepithelial acellular zone of 30 to 50 microns thickness appeared and persisted until at last 12 months after PRK.


Corticosteroids have a transient effect in reducing haze and seem to inhibit keratocyte movement, leading to an acellular subepithelial region beneath the ablated area.

[PubMed - indexed for MEDLINE]
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