RELEASE OF TGF-BETA-1 AND VEGF IN TEARS FOLLOWING PHOTOREFRACTIVE KERATECTOMY

Purpose. To study the presence and release of tear fluid transforming growth factor-beta 1 (TGF-beta 1) and vasoendothelial growth factor (V EGF) of 19 patients undergoing excimer laser photorefractive keratecto my. Methods. Tear fluid samples were collected with scaled microcapill ary tubes preoperatively (Day 0) and on the first or second (Day 1-2) and seventh (Day 7) postoperative days. Since postoperative tear fluid flow was significantly higher, we calculated the release of both grow th factors by multiplying the con concentration by the tear fluid flow in the capillary. Results. The median tear fluid flow in the capillar y was 8.1 mu l/ min (range 0.7-20.8) on Day 0, 46.3 mu l/min (3.1-135. 1) on Day 1-2, and 10.2 mu l/min (1.8-65) on Day 7. The median TGF-bet a 1 concentration and release values were: Day 0: 4.5 ng/ mi (0-23) an d 24 pg/min (0-257), Day 1-2: 9 ng/ml (0-32) and 446 pg/min (0-4602; p = 0.0014), and Day 7: 6.5 ng/ml (0-44) and 53 pg/min (0-470), respect ively. The median VEGF concentrations and releases were: Day 0: 19 ng/ ml (14-23) and 128 pg/min (11-458), Day 1-2: 15 ng/ml (11-20) and 695 pg/min (14-2567; p = 0.0007), and Day 7: 17.5 ng/ml (15-22) and 167 pg /min (27-1235), respectively. Conclusions. TGF-beta 1 and VEGF are com ponents of normal tear fluid. The significantly increased release of b oth growth factors after excimer laser photorefractive keratectomy may influence the corneal wound healing process.