Conjunctival Changes Induced by LASIK Suction Ring in a Rabbit Model

Abstract

Purpose: To study histopathological changes in rabbit conjunctiva after suction ring application. Methods: A suction ring was applied to adult albino rabbit eyes (n = 30) with a vacuum pressure of 508 mm Hg for 40 s. Three rabbits were sacrificed at 3 h (3-hour group), 6 h (6-hour group), 1 day (1-day group), 3 days (3-day group), and 7 days (7-day group) after the suction ring application. Histopathological examinations included hematoxylin and eosin, Alcian blue pH 2.5-periodic acid-Schiff (AB2.5-PAS), and Alcian blue pH 1.0-periodic acid-Schiff (AB1.0-PAS) staining. TdT-dUTP-terminal nick-end labeling (TUNEL) assay and immunohistochemical staining for p65 were also performed. Results: The site of suction ring application and adjacent areas did not show transient inflammation. AB2.5-PAS staining revealed that the percentage of neutral mucin was significantly different between 54.5 ± 1.6% in the control group and 22.3 ± 1.3% in the 7-day group (p = 0.04). Apoptosis occurred not only at the site of suction ring application, but also in adjacent regions. At all time points, conjunctival epithelium showed no positive staining for p65. Conclusion: The transient elevation of pressure induced by a suction ring is sufficient to cause conjunctival damage. These histological results support the finding that conjunctival damage caused by suction ring application is one of many etiologies of dry eye syndrome following laser in situ keratomileusis.