J Korean Ophthalmol Soc.  2002 Dec;43(12):2382-2390.

Correction of Myopic Astigmatism using Meditec Mel 70

• Heo JG
• Kim WS

Abstract

PURPOSE: The purpose of this study is to evaluate the efficacy of CCA (Cone for controlled Atmosphere) in Meditec Mel 70 Excimer laser in the extent of correction of myopic astigmatism in comparison with VISX 20/20 with Large beam.
METHODS
We evaluated 256 eyes of 132 patients who had been followed for 6 months or longer after LASIK. Group I included 126 eyes operated by Meditec Mel 70 excimer laser : in group Ia (35 eyes), Meditec Mel 70 was used without CCA setting, and in group Ib (91 eyes), Meditec Mel 70 with CCA setting. Group II included 130 eyes operated by VISX 20/20. We analyzed the clinical results of each group and compared with each other.
RESULTS
Mean preoperative astigmatic refraction was -0.93+/-0.42 diopter in group Ia, -1.12+/-0.89 diopter in group Ib, -1.06+/-0.79 diopter in group I and -1.30+/-1.06 diopter in group II. Six months after procedure, difference vector was -0.59+/-0.56 diopter in group Ia, -0.32+/-0.24 diopter in group Ib, -0.43+/-0.42 diopter in group I and -0.96+/-0.65 diopter in group II. The effect of astigmatic correction was more superior in group Ib than in group Ia, and in group I than in group II (P<0.01). At 6 months follow-up, residual astigmatism within +/-1.0 diopter was in 77.1% of group Ia, 96.7% of group Ib, 91.3% of group I, and 65.4% of group II. The deviation of the cylindrical axis was less in group Ib than in group Ia, and less in group I than in group II : 57.2% in group Ia, 86.8% in group Ib, 78.5% in group I and 57.7% in group II. Among eyes with mean preoperative astigmatic refraction over -1.50 diopter, group Ib and group I showed significantly better effect compared with group Ia and group II(P<0.01).
CONCLUSIONS
LASIK operation using Meditec Mel 70 of German Aesculap-Meditec company especially with CCA showed higher predictibility in the correction of myopic astigmatism. The more severe was the extent of astigmatism, the more excellent was the efficacy of correction.

Keyword

CCA (Cone for controlled Atmosphere); Difference vector; Meditec Mel 70 Excimer laser

MeSH Terms

Astigmatism*
Axis, Cervical Vertebra
Follow-Up Studies
Humans
Keratomileusis, Laser In Situ
Lasers, Excimer