Comparison of corneal histopathology changes between the rigid gas permeable contact lens wearers and the soft contact lens wearers

Abstract

Objective To investigate the corneal morphologic changes induced by wearing rigid gas permeable contact lenses (RGPCL) and soft contact lenses (SCL). Methods It was a case-control study. Sixty high myopia subjects participated in the study. Thirty were given RGPCL and 30 were given SCL Three, 6 and 12 months after wearing the contact lenses, confocal microscopy was used to observe the central and peripheral corneal epithelial cells, the density of the Langerhans cells,nerve fibers, corneal stroma, and endothelial cells of the 2 groups. A two-way ANOVA was used to analyze the data. Results Twelve months after contact lens wearing, the epithelial cell density of the corneal surface was lower in the SCL group than in the RGPCL group (F=4.262, P＜0.05), and corneal vesicles and corneal gutata were occasionally observed. The density of the Langerhans cells both in the central and peripheral cornea was higher in the SCL group (F=5.362, P＜0.05;F=-14.910, P＜0.05), and the tortuosity of the nerve fibers increased significantly in the eyes of those wearing SCL compared with those wearing RGPCL. The density of the anterior stromal cells was lower (P＜0.05) while the microdot densities in the stroma were higher in the SCL group than in the RGPCL group (P＜0.05). The polymorphology of the corneal endothelial cells was more apparent in the SCL group, but the density of the endothelial cells was similar for the 2 groups. The thickness of the central corneal epithelium was thinner for SCL wearers compared to RGPCL wearers (F=-2.061, P＜0.05). There were no differences for all of the indices within the same group at 3 months, 6 months and 12 months. Conclusion The corneal morphologic changes of RGPCL wearers are less severe than those of SCL wearers, suggesting that RGPCL wearing is a safe correction method. Key words: Contact lens,rigid gas permeable; Contact lens,soft; Histopathology; Confocal microscopy; Cornea