Comparison Wave Front-Guided and Cross Cylinder Photorefractive Keratectomy for Moderate-High Astigmatism

Introduction & This study was performed to compare the visual and refractive outcomes of photorefractive keratectomy (PRK) in eyes with medium-high astigmatism by WF-guided method using Visx system and cross-cylinder method using Nidek EC-5000 excimer laser system. Although there are many studies about efficacy and safety of Wave front guided and Cross Cylinder Photorefractive Keratectomy، there are few studies on moderate to high astigmatism. In a descriptive comparative study، WF-PRK was performed on 50 eyes of 25 patients with compound myopic astigmatism. Each patient underwent PRK by WF-guided approach. Then the results were compared with the cross-cylinder PRK previously performed on 48 eyes of 24 patients. After 6 months، 100% of the eyes in the WF group had uncorrected visual acuity of 20/25 or better compared to 79. 2% in the cross-cylinder group. Mean refractive astigmatism had decreased by 1. 57± 0. 53 in the WF group and 1. 67±0. 52 in the cross-cylinder group (P=0. 75). Mean postoperative absolute change in total root-mean-square higher order aberrations in the WF group and cross-cylinder group were 0. 05± 0. 22 µm and 0. 17±0. 20µm، respectively (P<0. 001). Both methods of PRK using the Nidek EC-5000 and visx excimer laser systems are effective for correcting medium-high astigmatism. WF approach is more successful in improving the refractive results.