The Predictability and Safety of 4-Incision Keratotomy for Myopia and Myopic Astigmatism

Objective: Incisional keratotomy (RK) and photorefractive keratectomy by excimer laser (PRK) are the 2 chief methods for surgical removal of myopia and astigmatism. This study of 100 eyes of consecutive patients who had RK performed in 1993 was done to set a bench-mark against which excimer laser (PRK) results could be compared. Study Design: Surgery was performed by a single surgeon in a day care surgical centre under local anaesthetic. The surgical study was restricted to 4-incision keratotomy with or without astigmatic surgery. All patients attended for follow-up which was up to 1 year. Patients: The range of refractive error treated was between −1.50 D and −6.75 D of myopia and between 1.25 D and 5.25 D of astigmatism. Coincident astigmatic surgery was done on 30% of cases and secondary enhancement surgery on 15% of cases. Main Outcome Measures: The aim of the surgery was −0.50 D and predictability was measured as a percentage of eyes correcting to within 0.50 D and 1.00 D. Loss or gain of best corrected visual acuity (BCVA) was assessed. Results: Eighty-three per cent of eyes were corrected to within 0.50 D and 98% corrected to within 1.00 D of the target of -0.50 D. Two eyes lost 1 line of BCVA and 5 eyes gained 1 line of BCVA. Conclusions: It is concluded that at this time 4-incision keratotomy achieves a higher predictability of result than any published results in the same refractive groups receiving excimer laser treatment.