Correction of Myopic Astigmatism using Meditec Mel 70

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.

Immunolocalization of Matrix Metalloproteinase-2, -9 and Tissue Inhibitor of Metalloproteinase-1, -2 in Suture-induced Corneal Neovascularization

PURPOSE: Metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) have been linked to the angiogenic process in general. In order to understand the potential roles of MMPs and TIMPs in corneal neovascularization process, we examined the expression and activities of MMP-2, MMP-9, TIMP-1 and TIMP-2 during the course of suture-induced corneal neovascularization in rat model. METHODS: Corneal neovascularization of rat cornea was induced by suturing. The expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in sutured corneas was examined by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The activities of MMP-2 and MMP-9 were measured before and after suture by gelatin zymography. RESULTS: MMP-2 proenzyme, and TIMP-1, -2 were expressed in normal corneas, predominantly in corneal epithelium. After injury, expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 increased, notably in healing corneal epithelium, infiltrating inflammatory cells, stromal fibroblasts, and ingrowing vascular endothelial cells. The intensity of immunostaining and enzymatic activities of MMP-2 and MMP-9 paralleled the magnitude of inflammatory cell infiltration, which peaked around day 7 after suture. Immunoreactivity of MMP/TIMP decreased significantly two weeks after suturing. At day 35 after suture, staining of MMP-2, TIMP-1, -2 remained visible only in corneal epithelium and vascular endothelial cells. CONCLUSIONS: MMPs as well as TIMPs were upregulated during suture-induced corneal neo-vascularization, suggesting that both may take part in extracellular matrix remodeling in the corneal wound healing, inflammatory, and neovascularization processes.