Photoastigmatic refractive keratectomy for low, moderate and high astigmatism using a broad beam excimer laser: evaluation according to new international criterias

Background Photorefractive keratectomy (PRK) is an accepted procedure to co rrect myopia in Germany. The purpose of this study was to evaluate photoast igmatic refractive keratectomy (PARK) for myopic astigmatism. Material and methods PARK using the VISX 20/20 excimer laser was performed in 50 eyes of 36 patients (25 female, 16 male) aged 22 to 68 years (mean 38 +/- 10 years) in the period of 1995 to 1996. Retrospective evaluation was done after dividing the patients into three astigmatic groups between -0.5 diopters (D) and -1.5 D (group I, n = 28), between -1.75 D and -3.0 D (grou p II, n = 16) und between -3.25 D and -5.5 D (group III, n = 6). The correc tion of myopic astigmatism was assessed concerning the criteria safety, eff icacy, predictability and stability. Mean follow-up was 12 months (8-15 mon ths). Results Seventy-eigth % of all eyes achieved an uncorrected visual acuity o f >0.5. Sixty-eight % of the eyes were within +/- 1.0 D of the desired corr ection. Loss of 2 or more lines of best corrected visual acuity occurred in 6 eyes (12.0%). We observed in group I an astigmatic reduction of 36.0% in group II of 66.5% and in group III of 68.0%. The surgically induced astigm atism was calculated with 1.29 +/- 1.0 D. Mean axis rotation of the refract ive cylinder was 22.12 +/- 23.05 degrees. Conclusions PARK using the VISX 20/20 excimer laser is an acceptable proced ure to correct myopic astigmatism. However, the study revealed that astigma tic reduction with a broad beam laser is not yet perfect in terms of effica cy, predictability and safety.