Mechanical Method Versus Laser Method for the Corneal Epithelium Ablation in Excimer Laser Photorefractive Keratectomy

ABSTRACT

Both mechanical ablation and laser ablation have been introduced for removal of the corneal epithelium in excimer laser photorefractive keratectomy(PRK). We analyzed the differences of the clinical outcome between mechanical ablation and laser ablation on 256 consecutive eyes followed up more than 6 months after PRK from August 1991 to June 1993. During the follow up period. pre- and post- operative visual acuity, refractive errors, corneal clarity, epithelial healing time, post-operative pain, and central island were compared between two groups. Anova and X2 test were used for statistical analysis. The uncorrected visual acuity at 6 months after operation was 0.81 in group A and 0.75 in group B(p<.05). The degree of corneal haziness was more severe in group B than group A at 6 months after operation(p<.05). Mean refractive errors and keratometer readings were not statistically signigicant between two groups. Average epithelial healing times after operation were 3.18 days in group A and 2.73 days in group B(p<.001). The incidence ot central island was lower in group B than in group A(p<.001). Post-operative pain was less severe in group B than in group A. This results suggest that mechanical ablation seems to achieved better visual acuity and less complication than laser ablation for removal of the corneal epithelium in PRK.