Extended-wear soft contact lens and corneal epithelium apoptosis

Purpose. We reported that extended-wear soft contact lens (EWSCL) wearer's human superficial corneal epithelial cell size were larger than normal's. But this mechanism is unknown. We think the mechanism may be produced by decreasing an impulse to epithelial cells by blinking or EWSCL wearer inhibiting a corneal epithelium apoptosis. In this study we analyzed EWSCL wearers and normal rabbit corneal apoptosis. Methods. EWSCL was placed on white rabbit eye for one month. The other eye was used as the normal control. We analyzed superficial corneal epithelial cell size, using specular microscope. Apoptosis was detected by using the APOPTAG™ (ONCOR Co LTD.), apoptosis detection kit. Results. The initial superficial corneal epithelial cell size of 570±251 μm² changed after one month 945±370 μm². Staining, which indicates DNA fragmentation, was detected in only the upper 2 to 3 layers of the corneal epithelium. Stronger staining was observed in the normal control corneal epithelium. Conclusions. EWSCL wearer's corneal epithelial cell size increased and apoptosis cells decreased. These findings indicate that EWSCL wear may inhibit the programmed cell death of the corneal epithelium.