Fluorophotometric Detection of Oxygen Free Radicals in the Cornea and Lens after Excimer Laser Photore fractive Keratecto my in Rabbit

Heo, Jun Ho; Wee, Won Ryang; Lee, Jin Hak

Abstract

This study was performed to detect the oxidative stress in the cornea and lens in vivo by fluorophotometer after excimer laser photorefractive keratectomy(PRK). Twenty New Zealand white rabbits(20 eyes)were divided into two groups, control group(10 eyes)and PRK group(10 eyes). Rabbits of PRK group underwent PRK(8 diopters)and 2', 7'-dichlorofluorescein diacetate(DCFH-DA)was applied on the central cornea 6 hours after PRK in both groups. Fluorophotometric readings of the cornea and lens were measured 15 minutes(F15)and 30 minutes(F30)after DCFH-DA application in both groups. The cornea and lens was observed with slit lamp biomicroscope for 8 weeks. F15 and F30 of the cornea in PRK group(3.83+/-1.22 ng/ml, 5.12+/-1.57 ng/ml)were significantly higher than those in control group(2.61+/-0.59 ng/ml Eq, 3.26+/-0.76 ng/ml Eq)(p=0.01, p=0.005). F15 and F30 of the lens in PRK group(409.7+/-157.2 ng/ml, 594.9+/-242.2 ng/ml Eq)were significantly higher than those in control group(74.1+/-48.3 ng/ml Eq, 310.1+/-249.8 ng/ml Eq)(p=0.0004, p=0.01). No lens opacity developed and F15 and F30 of the cornea did not correlate with corneal haze determined at postoperative 8 weeks. In this study, we demonstrated increased oxygen free radicals in the cornea and lens after PRK by fluorophotometer in vivo and this method can be used as a useful tool to investigate the possible damage induced by oxygen free radicals in the cornea and lens after excimer laser corneal ablation.