The Evaluation of Contrast Sensitivity and Glare after LASIK Using Flying Spot Mode Laser According to Pupil Diameter and Refractive Error

PURPOSE: To study the effect of LASIK using flying spot mode laser on contrast sensitivity and glare according to pupil diameter and preoperative refractive error. METHODS: Fifty seven eyes of 42 patients had LASIK using MEL 70 G-scan (Asclepion Meditec, Germany) to correct myopia ranging from -2.50 to -10.50 diopter (D). The contrast and glare sensitivity were measured preoperatively and 1 week, 1 month and 3 months after LASIK using CGT-1000 (Takagi, Japan). RESULTS: The mean preoperative spherical equivalent (SE) was -5.4+/-2.9D. The mean pupil diameter was 5.95+/-0.46 mm in scotopic condition. Contrast sensitivity was significantly reduced 1 month after LASIK, depending on pupil diameter and degree of preoperative myopia. However, values returned to preoperative figures thereafter (P<0.05). Glare sensitivity was improved at all frequencies 3 months after LASIK, and most significantly at high frequency (P=.031). CONCLUSIONS: LASIK using employing the flying spot mode laser can effectively accomplish refractive correction without reduction of preoperative contrast and glare sensitivity values.

The Translocation of Nuclaer Factor Kappa B on Corneal Epithelial Cells after Ultraviolet B Irrradiation

PURPOSE: To seek the role of nuclear factor kappa B (NF-kB) on the corneal epithelial cell death after ultraviolet (UV) irradiation. METHODS: Human corneal epithelial cells transfected by Simian Virus 40 were used in this study. UVB(312 nm) located at 10cm distance from bottom (0.6 mW/cm2 ) was irradiated for 10, 20, 30, and 40 seconds. To measure the cytotoxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method was used. Translocation of NF-KB was examined by immunocytochemistry with anti NF-K B p65 antibody and Electrophoretic Mobility Shift Assay (EMSA). To confirm the role of NF-KB , sulfasalazine, a specific inhibitor of NF-KB (0.5 mmole), was pretreated for 30 minutes before irradiatrion, and cytotoxicity and translocation of NF-KB was evaluated. RESULTS: UV irradiation resulted in a significant decrease in viability of cultured human corneal epithelial cells, especially after 20 second duration. When HCECs were irradiated with UVB, the translocation of N F -KB was observed in immunocytochemistry. These translocation was peaked 2 hours after UV irradiation in EMSA. In HCECs pretreated with sulfasalazine, either the cellular death or the translocation of NF-KB was blocked. CONCLUSION: UV irradiation can translocate NF-KB on the cultured human corneal epithelial cells. The cellular death after UV irradiation was blocked by sulfasalazine, a potent inhibitor of translocation of NF-KB. These findings suggest that NF-KB plays an important role in cellular death after UV irradiation.