Basement Membrane and Collagen Deposition After Laser Subepithelial Keratomileusis and Photorefractive Keratectomy in the Leghorn Chick Eye

Methods: Leghorn chick corneas treated with LASEK surgery (using 20% ethanol for 30 seconds) or PRK were evaluated by indirect confocal immunofluorescence and transmission electron microscopy at 1, 2, 7, 14, and 28 days after surgery. New collagen deposition was determined by dichlorotriazinylaminofluorescein staining 2 and 4 weeks after surgery. Results: Laminin was detected around the basal layers during the immediate postoperative period and 4 weeks after LASEK surgery, and from day 2 onwards after PRK. Collagen III deposition in the cornea was about 3 times greater with PRK than with LASEK. The thickness of new collagen deposition at 4 weeks was 34 µm±2.5 µm in the PRK group, which was significantly greater than that of the LASEK group (11 µm±1 µm; P.001). Conclusions:ReducedsubepithelialstromaltissuedepositionwasobservedinLASEK-treatedeyescomparedwith PRK-treated eyes. Postoperative preservation of the epithelialbasementmembraneandsurvivalofepithelialcells in LASEK and possibly in epithelial laser in situ keratomileusis may contribute to this phenomenon.