The Reduction of the Postkeratoplasty Astigmatism by Excimer Laser and Diamond Knife Procedure

ABSTRACT

PURPOSE: To evaluate the efficacy of excimer laser PRK (PAK) and arcuate keratotomy (AK) for correction of post-keratoplasty astigmatism. METHODS: We performed AK in 13 patients and PAK in 8 patients who had astigmatism over 3.5 D, and who could not wear contact lens or spectacles. We follow up patients in early phase (1~3 months) and late phase (6~12 months) after operation. Net change in astigmatic magnitude , uncorrected visual acuity, and best corrected visual acuity were examined. Surgery-induced astigmatism was calculated by bector anaysis method. RESULTS: Mean preoperative astigmatism in AK patients was 8.23+/-3.25 D and in PAK patients was 7.84+/-1.58 D. Astigmatic magnitude was decreased 61.2% in early phase, 58.3% in late phase in AK patients and decreased 51.4% in early phase, 41.2% in late phase in PAK patients. Post operative astigmatic axis was changed within 30 degrees 76.9% in early phase, 61.5% in late phase in AK, and 50% in early phase, 37.5% in late phase in PAK. Postoperative uncorrected visual acuity showed stastically significant improvement in early and late phase in AK patients and late phase in PAK patients. Postoprative best corrected visual acuity improved 53.8% in AK patients and 50% in PAK patients above 2 Snellen chart lines, but both was not stastically significant. Postoperative complication was mild haze not interfering refraction and visual acuity in 5 eyes of PAK. CONCLUSIONS: AK corrected astigmatsm and visual acuity more rapidly than PAK in early phase, but more undercorrected in late phase. Mild haze was developed in PAK. But AK and PAK show nearly same astigmatic and visual correction results in conclusion.