Corneal light scattering with stromal reformation after laser in situ keratomileusis and photorefractive keratectomy

Abstract

Objective: To correlate corneal light scattering with keratocyte and extracellular matrix reformation after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).Setting: Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, Maryland, USA.Methods: Sixteen pigmented rabbit eyes were randomly divided Into 2 groups. Group 1 (n=8) had a 5.0 mm, -10.0 diopter (D) LASIK treatment and Group 2 (n=8), a 6.0 mm, -10.0 D surface PRK treatment after mechanical epithelial debridement. The stromal surface exposed at surgery was stained with dichlorotriazinylaminofluQrescein (DTAF) solution. Slitlamp biomicroscopic and objective measurement of corneal light scattering using a scatterometer were performed 1 and 2 days and 1, 2, 3, 4, 8, and 12 weeks after surgery. In each group, 2 corneas were harvested at 1 week and 1 month and 4 corneas were harvested at 12 weeks. Tissue sections were examined by light and fluorescence microscopy. The percentage of newly formed stromal tissue was calculated and correlated with the scatterometry index.Results: In Group 1, corneas remained clear and healed without significant scarring throughout the study. In Group 2, subepithelial scarring was noted. Extracellular matrix reformation peaked at 1 month and showed a slight regression thereafter. The percentage of extracellular matrix reformation was strongly correlated with the scatterometry index (r = .86, P < .001).Conclusions: In this study, significant subepithelial stromal tissue reformation followed PRK. The percentage of extracellular matrix reformation correlated well with the objective corneal light scattering measurements.