Photorefractive keratectomy for astigmatism with the Meditec MEL 60 laser

PURPOSE: To evaluate the results of photorefractive keratectomy (PRK) in eyes treated with astigmatic refractive errors. METHODS: Nine hundred forty eyes were treated with the Aesculap Meditec MEL 60 ArF excimer laser. Treatment groups were: Group 1 (n=746) eyes with compound myopic astigmatism, Group 2 (n=104) eyes with compound hyperopic astigmatism, Group 3 (n=75) eyes treated for mixed astigmatism, and Group 4 (n=15) eyes with simple myopic astigmatism (negative cylinder). RESULTS: In Group 1, the preoperative spherical equivalent refraction of-6.10 D with an average of-1.50 D cylinder decreased to -0.95 D with -0.13 D cylinder; uncorrected visual acuity (UCVA) of 20/40 or better was achieved in 86% (642/746 eyes); 20/20 or better in 58% (433/746 eyes); 0.8% (6/746 eyes) lost two lines of spectacle-corrected visual acuity (SCVA); 74% (552/746 eyes) were within ±0.50 D and 93% (694/746 eyes) were within ±1.00 D of target refraction. In Group 2, preoperative mean +4.57 D spherical equivalent refraction with an average of +1.57 D cylinder decreased to +1.13 D with +0.38 D cylinder; UCVA of 20/40 or better was achieved in 84% (87/104 eyes); 20/20 or better in 46% (48/104 eyes); 14,4% (15/104 eyes) lost two or more lines of SCVA; 52% (54/104 eyes) were within ±0.50 D and 82% (85/104 eyes) were within ±1.00 D of target refraction. In Group 3, mean preoperative -4.20 D cylinder and +3.00 D spherical equivalent refraction decreased to -0.50 D cylinder and -0.50 D spherical equivalent refraction; UCVA of 20/40 or better was achieved in 83% (62/75 eyes); 20/20 or better in 32% (24/75 eyes); 13.3% (10/75 eyes) lost two or more lines of SCVA. In Group 4, mean preoperative -3.98 D cylinder decreased to -0.62 D cylinder; UCVA of 20/40 or better was achieved in 60% (9/15 eyes); none of the eyes achieved 20/20 or better; SCVA remained stable in 6.6% (1/15 eyes) and decreased two or more lines in 20.0% (3/15 eyes); 20% (3/15 eyes) were within ±0.50 D and 53.3% (8/15 eyes) were within ±1.00 D of target refraction. CONCLUSION: PRK with the Meditec MEL 60 laser produced the best results in eyes with compound myopic astigmatism (Group 1). In all other groups, results were less predictable.