[A prospective clinical study of correction of myopic astigmatism by combined treatment with PRK and T-incision and photoastigmatic refractive keratectomy. The results after one year].
BACKGROUND
In contrast to the correction of simple myopia there is no widely accepted technique for the correction of myopic astigmatism. Currently two techniques are available: the photoastigmatic refractive keratectomy (PARK) and the combination of arcuate keratotomies with standard PRK (PRK-T).


METHODS
In two groups, 67 patients underwent a correction of myopic astigmatism in a total of 87 eyes (19 by PRK-T and 68 by PARK), and were followed for 1 year. The spherical equivalent was -6.7 D in both groups and the refractive astigmatism ranged from -1.0 to -6.5 D. The PARK procedure was performed by means of an elliptic ablation (Kertom I, Schwind) with a 5.8 x 8.1 mm zone. The PRK-T technique consisted of two arcuate keratotomies with a free optical zone of 7 mm and a standard myopic PRK at least 6 weeks later.


RESULTS
The 1 year follow-up was completed in 57 out of 87 eyes included in the study. At 1 year post-operation, 83% of the PRK-T group and 80% of the PARK group had an uncorrected visual acuity of 20/40 or better. The refractive astigmatism was reduced by 76% in the PRK-T group and by 67% in the PARK group. The spherical equivalent was -0.59 +/- 1.1 D at 1 year after PRK-T and -0.28 +/- 1.04 D after PARK. In three eyes of the PARK group (6.7%) a visual loss of more than one Snellen line occurred. Two of these eyes had a preoperative myopia of more than -6 diopters.


CONCLUSIONS
Both techniques have the potential to reduce myopic astigmatism, however, the success rate is not as high compared to spherical PRK. Also, the complication rate of 2.5% in corrections to -6 D is significantly higher than that with spherical myopic PRK.
Alkara
N
N
Augenklinik im Universitäts-Klinikum Carl Gustav Carus der Technischen Universität Dresden.
Genth
U
U
Seiler
T
T
D000328:Adult; D001251:Astigmatism / Q000534:rehabilitation* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects / Q000379:methods; D018903:Photorefractive Keratectomy / Q000009:adverse effects / Q000379:methods*; D011446:Prospective Studies
Astigmatismuskorrektur mittels PRK kombiniert mit T-Inzision und photoastigmatischer Keratektomie. Einjahresergebnisse einer prospektiven klinischen Studie.