Corneal Endothelial Damage after Deep Excimer Laser Ablation

ABSTRACT

To investigate the effect of deep excimer laser ablation on the corneal endothelium, excimer laser photo refractive keratectomy(PRK) with different ablation depths were performed to obtain various residual corneal thickness(range 90-250 micrometer) in white rabbit corneas(N=50). Corneal endothelium was stained with Alizarin red S(pH 4.2) for 2 minutes three days after excimer laser ablation and was analyzed morphometrically using digitizer the morphometric parameters according to residual corneal thickness. In the corneas of residual corneal thickness(RT) over 200 micrometer and untreated controls(N=6), endothelial damages were rarely seen. With the decrease of residual corneal thickness, hexagonality and shape factor decreased, and coefficient of variation of the cell area(CV) increased(p<0.01). In corneas of RT less than 200 micrometer, endothelial damages were found and become more severe in corneas of RT between 90~149 micrometer. Hexagonal shaped cells were rarely observed, and the shapes of most cells were changed. Deep excimer laser PRK might affect corneal endothelial cells if the RT is less than 200 micrometer, and these findings suggest that care is recommended when doing deep excimer laser corneal ablation, especially excimer laser assisted in situ keratomileusis.