Photorefractive keratectomy with the 193-nm excimer laser is one of the most promising innovations in refractive surgery. However, routine clinical application is hindered by two main obstacles, i.e., postoperative subepithelial opacity and possible regression of the refractive result. Because we have previously demonstrated beneficial effects of basic fibroblast growth factor (bFGF) on corneal epithelial healing in different in vivo models, we investigated the influence on both epithelial and stromal healing of topical bFGF after excimer laser keratomileusis in a rabbit model. After 7-mm circular deepithelialization, the eyes of 24 New Zealand White rabbits received identical deep stromal laser ablations (depth 50 µm, 6 D, diameter 5 mm) and were randomly assigned to one of four treatment groups [control (phosphate-buffered saline, PBS), bFGF 10 µg/application, dexamethasone 0,1%, bFGF + dexamethasone, n=12 eyes/group]. All treatments were administered four times daily—bFGF until complete epithelial healing, dexamethasone and PBS until 3 months postsurgery. Wound surface regression on time was determined by means of computer-assisted image analysis of fluorescein-stained corneas. Corneal opacity was observed biomicroscopically and graded using a previously established scoring system. After bFGF application for 2-3 days only, a highly significant acceleration in epithelial wound healing speed was found compared with the rate of the other three treatment groups (p<0.001). A combined therapy (bFGF + steroid) had no effect on the healing rate. Compared with control values, mean scores for subepithelial haze in the other groups were found to be nearly 50% lower during the first 2 postoperative months. No significant difference could be seen between eyes that received bFGF, dexamethasone, or bFGF + steroid. These results demonstrate for the first time the efficiency of a growth factor in modulating the wound healing response after excimer laser photoablation. Also with regard to possible adverse reactions, a short-term and low-dose bFGF application seems advantageous over a continuous treatment with corticosteroid drugs.
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