The Analysis of Corneal Topography after Laser in Situ Keratomileusis(LASIK) for Myopic Correction

PURPOSE: To investigate the patterns of corneal topography after LASIK METHODS: The author have performed LASIK to correct the myopia of 21 male and 34 female patients. The corneal topography was performed at preoperative state and 2 days, 1, 3, 6, 12months after operation. RESULTS: Differential maps were classified using a standard eight-category classification scheme which were divided into a combined regular group(toric-with-axis, toric-against-axis, homogeneous, focal topographic variant) and a combined irregular group(semicircular, irregularly irregular, central island, keyhole). At 2 days, the distribution of corneal topographic patterns was 61.8% in a combined regular group and 38.2% in a combined irregular group. Of all patterns, the homogeneous pattern was predominant. The best corrected visual acuity was better in a combined regular group than in a combined irregular group which was statistically significant. After postoperative 1 month, most irregular patterns had a change in topography, generally to an optically smoother pattern. CONCLUSIONS: Corneal topography has been established as an invaluable tool for refractive surgery and this analysis allows the recognition of normal and abnormal patterns of ablation following excimer laser surgery.

Change in Fluorescein clearance and Tear Film Stability following Laser in situ Keratomileusis

PURPOSE: To study the change in corneal sensitivity, tear film stability, tear clearance and blink rate after LASIK. METHODS: The authors have performed LASIK to correct the visual acuity in myopia of 3 males and 18 females(42 eyes). The corneal sensitivity(Cochet-Bonnet esthesiometer), tear film break-up time, fluorescein clearance and blink rate were measured prior to operation, 2 weeks, 1 and 3 months after LASIK. RESULTS: There was decrease in corneal sensitivity after LASIK, which did not recover to the pre-operative level by 3 months after LASIK. To restore corneal sensitivity, more time was needed for regrowth and maturation of the nerve fiber. The decrease in BUT scores 1 and 3 months after LASIK was statistically significant. The decrease in blink rate after LASIK was also statistically significant. The increase in FCT concentration grade was not statistically significant. There was a trend toward a reduction in blink rate in the group with more correction. CONCLUSIONS: Symptoms suggestive of relative tear deficiency such as foreign-body sensation, visual fluctuation and absence of reflex tear have described after LASIK. Change in corneal sensitivity, tear film stability and blink rate were associated with such dry eye symptoms.

A Case of Endophthalmitis after Laser in situ Keratomi leusisLASIK

Laser in situ keratomileusis[LASIK] is a refractive surgical procedure that is effective in treating myopia and astigmatism. The incidence of corneal infection after LASIK is approximately 0.02% according to international experience. We experience the case of a 20-year old man who developed endophthalmitis; corneal edema, epithelial defect, hypopyon was found 2 days after LASIK. He was immediately given intravenous and subconjuntival injection[tobramycin and ceftazidime] and topical fortified eyedrop[tobramycin and ceftazidime]. The microbiologic study revealed Serratia marcescens as the causative organism. Three days after therapy was instituted, the hypopyon resolved. After 4 months of LASIK, visual acuity was 1.0 and maintained recently. We report a case of endophthalmitis after LASIK by Serratia marcescens which detected early and treated by antibiotics. In addition, close postoperative surveillance and education for hygiene was required on early postoperative period.