Comparison of Laser Epithelial Keratomileusis(LASEK) in One Eye and Photorefractive Keratectomy(PRK) in Other Eye for Low to Moderate Myopia

PURPOSE: To assess effectiveness, safety and stability of laser epithelial keratomileusis(LASEK), versus conventional photorefractive keratectomy(PRK) for low to moderate myopia. METHODS: 27 patients with a manifest refraction of -3.00 to -6.50 diopters were treated and followed-up for 3 months. In each case, one eye received PRK and the other LASEK. The surgical method and the sequence between the eyes were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity, manifest refraction, corneal haze and surgical preference were examined after the operation. RESULTS: During a 3-month-follow-up, we found no significant differences in epithelial healing time, uncorrected visual acuity and refractive error. However, LASEK treated eyes had lower postoperative pain scores(P=0.047), and corneal haze scores(1 month; P=0.02) than those of PRK. Seventeen patients(63%) preferred the LASEK procedure. CONCLUSION: LASEK and PRK has an equal effect in correction of myopia, but LASEK reduced incidence of postoperative pain and early postoperative corneal haze. This suggests LASEK can be an alternative procedure for correction of low to moderate myopia.

The Clinical Results of Vitrectomy in Proliferative Diabetic Retinopathy with Diabetic Nephropathy

Many patients undergoing vitrectomy due to proliferative diabetic retinopathy also have diabetic ephropathy.Hence, to figure out the surgi-cal results of vitrectomy and the survival rate after vitrectomy in diabetic patients having diabetic nephropathy, we reviewed medical records of 70 patients[83 eyes]who had been followed for 3 months or longer after vitrectomy. Among them, 28 patients[33 eyes]were complicated by diabetic nephropathy.Visual acuity improved in 21 out of 33 eyes [63.6%]among the patients with nephropathy while vision improved in 29 out of 50 eyes[58.0%] among those without nephropathy.The two groups showed significant improvement of visual acuity postoperatively and the difference in visual acuity improvement between two groups was not statistically significant. The factors which affected postoperative visual acuity improvements in patients with diabetic nephropathy were preoperative panretinal photocoagulation[p=0.013]and intraoperative intraocular silicone oil injection[p=0.021]. Rate of occurrence of complications after vitrectomy and the types of the complications were similar in the two groups. During the 4-year follow up, 4 of 11 patients who had been on peritoneal dialysis or emodialysis died. These results showed that the result of vitrectomy for proliferative diabetic retinopathy in patients with iabetic nephropathy was not poor and suggested that diabetic nephropathy might not be a contraindication of vitrectomy for proliferative diabetic retinopathy.

The Quantitative Analysis of Effectiveness of Radiation Therapy on Choroidal Ne ovascular Membra n e s

The natural course of visual acuity of choroidal neovascularization (CNV) membrane is known to be poor.When fovea is involved, only a subset of patients is eligible for laser photocoagulation or alternative treatment odalities.Radiation therapy has been investigated for applying to such cases, however there have been controversies among reports on the effec-tiveness of radiation therapy.Hence we intended to evaluate the effective-ness of radiation therapy quantitatively.Twenty-one eyes with subfoveal CNV were treated with 4 MV X-ray (total dose of 20 Gy).After the follow-up period of 6months or longer, the visual acuity remained stable or improved from the initial visual acuity in 15 of 21 eyes (71.4%). Based on indocyanine green (ICG)video angiography, the CNVs decreased in their size in 16 of 21 eyes (76.2%)and this difference was statistically significant. These results suggest that radiation can induce regression of subfoveal CNV and maintain central vision in a significant number of patients and we believe that larger, longer study is necessary.

The Differences of IOP and Factors Influencing IOP Measured by Goldmann Applanation Tonometer after Photore fractive Keratectomy and Laser In Situ Keratomileusis in Myopic Eyes between -4~-7 Diopters

To evaluate the differences and factors to be considered when measuring intraocular pressure after photorefractive keratectomy[PRK]and laser in situ keratomileusis[LASIK], we prospectively reviewed the medical records of myopic eyes between -4~-7 diopters. Among them, 14 patients, 22 eyes underwent PRK and 10 patients, 18 eyes recieived LASIK. We measured intraocular pressures by Goldmann applanation tonometry preoperatively, 1 month, 3 months and 6 months postoperatively in each group. Corneal curvatures, central corneal thicknesses were measured and compared when measuring intraocular pressure. The postoperative intraocular pressure was lower than the preoperative value in both groups[p<0.01], and the decreased amount of IOP were not statistically different in both groups[p=0.29]. Targeted ablation depth[p=0.19]and ablation diameter[p=0.16]did not show statistically significant correlation to postoperative IOP decrease. In measuring intraocular pressure after PRK or LASIK, attention should be given to the pressure and its interpretation.

The Differences of IOP and Factors Influencing IOP Measured by Goldmann Applanation Tonometer after Photore fractive Keratectomy and Laser In Situ Keratomileusis in Myopic Eyes between -4~-7 Diopters

To evaluate the differences and factors to be considered when measuring intraocular pressure after photorefractive keratectomy[PRK]and laser in situ keratomileusis[LASIK], we prospectively reviewed the medical records of myopic eyes between -4~-7 diopters. Among them, 14 patients, 22 eyes underwent PRK and 10 patients, 18 eyes recieived LASIK. We measured intraocular pressures by Goldmann applanation tonometry preoperatively, 1 month, 3 months and 6 months postoperatively in each group. Corneal curvatures, central corneal thicknesses were measured and compared when measuring intraocular pressure. The postoperative intraocular pressure was lower than the preoperative value in both groups[p<0.01], and the decreased amount of IOP were not statistically different in both groups[p=0.29]. Targeted ablation depth[p=0.19]and ablation diameter[p=0.16]did not show statistically significant correlation to postoperative IOP decrease. In measuring intraocular pressure after PRK or LASIK, attention should be given to the pressure and its interpretation.