[A specular microscopic study on irradiated rabbit corneas--report I. Early injury of the cornea]

To evaluate the effects of ionizing radiation on the cornea, one eye of healthy mature albino rabbits (n = 5) was irradiated with 20 Gy of X-rays (250 kV, 12 mA). Corneal observation was done with a slit-lamp biomicroscope and a specular microscope before irradiation, and follow-up observations were done at one week and 4 weeks after irradiation. Specular microscopic photographs were analyzed with a digitizer. Although slit-lamp biomicroscopy did not show any abnormal findings in the cornea, specular microscopy revealed a significant enlargement of the mean cell area of the superficial corneal epithelium at 4 weeks after irradiation. There were no significant changes in the corneal endothelium during this study. These results strongly suggest that high doses of X-ray irradiation could induce corneal epithelial injury at the early phase, even when by slit-lamp biomicroscopy shows no abnormal findings in the cornea.