Apoptosis, XXXX , proliferation, and myofibroblast generation in the stroma following LASIK and PRK.

@entity32 @entity9977 @entity267 @entity39 @entity95 @entity1714
The aim of this study was to semi-quantitatively analyze stromal cell apoptosis, stromal cell proliferation, and myofibroblast generation over time points from 4hr to 3 months in @entity95 eyes having photorefractive keratectomy (PRK) or laser in situ keratomeliusis (LASIK). @entity39 and @entity32 were also studied. PRK for @entity1714 (-4.5diopters [D]), PRK for @entity1714 (-9.0D), and LASIK for @entity1714 (-9.0D) were performed in @entity95 eyes, and corneas were obtained for examination at 4, 24, and 72hr, 1 and 4 weeks, and 3 months after surgery. A total of 144 @entity95 were included in the study. Stromal cell apoptosis, proliferation, and myofibroblast generation were evaluated semi-quantitatively by TUNEL assay, immunocytochemical analysis of Ki67, and immunocytochemical analysis of @entity9977 , respectively. @entity39 and characteristics of other cell types in the stroma were evaluated by electron microscopy. Keratocyte apoptosis and the subsequent proliferation and generation of myofibroblasts were qualitatively and quantitatively different in PRK for @entity1714 compared to either PRK for @entity1714 or LASIK for @entity1714 . @entity39 becomes a significant form of cell death by 24hr after injury and may involve corneal fibroblasts, myofibroblasts, and inflammatory cells. Large numbers of polymorphonuclear cells and monocytes invade the @entity267 by 24hr after surgery and persist for over 1 week. The qualitative and quantitative differences in the cellular wound healing response after PRK for high and @entity1714 and LASIK for @entity1714 are likely determinants of the clinical differences in refractive outcome and some of the complications, such as regression and haze, seen after these procedures.
