Changes in higher order aberrations after wavefront-guided PRK for correction of low to moderate myopia and myopic astigmatism: two-year follow-up.
OBJECTIVE
To assess efficacy, safety, and changes in higher order aberrations after wavefront-guided photorefractive keratectomy (PRK) in comparison with conventional PRK for low to moderate myopia with myopic astigmatism using a WASCA Workstation with the MEL 70 G-Scan excimer laser.


METHODS
A total of 126 myopic or myopic-astigmatic eyes of 112 patients were included in this retrospective study. Patients were divided into two groups: Group 1, the study group; and Group 2, the control group. Group 1 consisted of 78 eyes treated with wavefront-guided PRK. Group 2 consisted of 48 eyes treated with spherocylindrical conventional PRK.


RESULTS
Two years postoperatively, in Group 1, 5% of eyes achieved an uncorrected visual acuity (UCVA) of 0.05; 69% achieved a UCVA of 0.00; 18% of eyes experienced enhanced visual acuity of -0.18 and 8% of -0.30. In Group 2, 8% of eyes achieved a UCVA of 0.1; 25% achieved a UCVA of 0.05; and 67% achieved a UCVA of 0.00 according to logMAR calculation method. Total higher-order root-mean square increased by a factor 1.18 for Group 1 and 1.6 for Group 2. There was a significant increase of coma by a factor 1.74 in Group 2 and spherical aberration by a factor 2.09 in Group 1 and 3.56 in Group 2.


CONCLUSIONS
The data support the safety and effectiveness of the wavefront-guided PRK using a WASCA Workstation for correction of low to moderate refractive errors. This method reduced the number of higher order aberrations induced by excimer laser surgery and improved uncorrected and spectacle-corrected visual acuity when compared to conventional PRK.
1st Department of Ophthalmology, Silesian University of Medicine, ul. Caglana 35, 40-952 Katowice, Poland. iza@kli-okul.katowice.pl
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Wigledowska-Promienska
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Zawojska
D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D003315:Cornea / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D017060:Patient Satisfaction; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*