PURPOSE: Suction ring is needed to fix the cornea during LASIK procedure. But if we choose the suction ring inappropriately, we meet the various problems such as conjunctival edema, conjunctival hemorrhage, ocular pain, and prolongation of operation time. To investigates various factors affecting the thickness of suction ring(1-4) in LASIK procedure. METHODS: We performed LASIK procedure by using SCMD microkeratome and VISX STAR laser on 398 eyes from Dec. 1996 to Feb. 1999. We compared difference on pachymetry, keratometry, corneal diameter, spherical equivalent according to the thickness of suction ring and analyzed these factors with One-Way ANOVA test. RESULTS: The results are that keratometry affected size of suction ring significantly. The flap size and hinge size are affected by size of suction ring significantly, but others did not show significant results. CONCLUSIONS: These results suggest that we need to choose the size of suction ring according to keratometry during LASIK procedure for decreasing various complications.
Cornea ; Edema ; Hemorrhage ; Keratomileusis, Laser In Situ* ; Suction*

In this study, we investigated whether retinal soluble proteins, such as interphotoreceptor retinoid-binding protein(IRBP), play a role in the induction of nitric oxide by macrophages in vitro. Cells from the murine macrophage cell line RAW 264.7 and rat and rabbit peritoneal macrophages were incubated in the presence of retinal soluble protein. The nitrite level in the cultured supernatant was evaluated for nitric oxide production using the Griess reaction. IRBP induced significant, dose-dependent nitrite production in both RAW 264.7 and rat peritoneal macrophages. Induction of inducible nitric oxide synthase (iNOS) by retinal proteins was inhibited by the iNOS-specific inhibitor, aminoguanidine, and the tyrosine inhibitor, genistein. These results show that soluble retinal proteins significantly induce nitric acid production by macrophages. Increased production of reactive oxygen species by macrophages in the presence of this soluble retinal protein in vivo may accelerate photoreceptor degeneration in uveitis.
Animal ; Cell Line ; Comparative Study ; Enzyme Inhibitors/pharmacology ; Eye Proteins/pharmacology* ; Guanidines/pharmacology ; Macrophages, Peritoneal/metabolism ; Macrophages, Peritoneal/drug effects* ; Macrophages, Peritoneal/cytology ; Nitric Oxide/biosynthesis* ; Nitric-Oxide Synthase/metabolism ; Nitric-Oxide Synthase/antagonists & inhibitors ; Rabbits ; Rats ; Rats, Inbred Lew ; Retinol-Binding Proteins/pharmacology*

We performed spherical LASIK operations using manual microkeratome and assessed the axis and magnitude of surgically induced astigmatism by vector analysis[Jaffe's rectangular coordinates]. Six month follow-up of 124eyes of 98 patients who were followed for 6 months or longer were included. Myopia ranged from -4.00 to -9.75 diopter. We divided eyes depending on the degree of myopia;group 1, 31 eyes between -4.00 and -5.75 diopter, group 2, 46 eyes between -6.00 and -7 .75 diopter, and group 3, 47 eyes between -8.00 and -9.75 diopter. Also, we compared the axis of surgically induced astigmatism between right eyes[73 eyes]and left eyes[48 eyes]. Preoperative astigmatic refraction was -0.63 +/-0.30 diopter in group 1, -0.67 +/-0.35 diopter in group 2, -0.67 +/-0.41 diopter in group 3.After 2 months, magnitude of surgically induced astigmatism was 0.84 +/-0.57 diopter in group 1, 1.08 +/-0.72 diopter in group 2, 1.19 +/-0.84 diopter in group 3[P=0.15], after 6 months, 1.01 +/-0.59 diopter in group 1, 1.16 +/-0.98 diopter in group 2, and 0.99 +/-0.59 diopter in group 3[P=0.52]. Change in the axis of vectorial-induced astigmatism was not statistically significant between right eyes and left eyes after 2 months[P=0.16], but significant after 6 months[p<0.05 ]. In conclusion, spherical LASIK using manual microkeratome may induce a significant change in magnitude of the astigmatism regardless the degree of myopia. The difference of astigmatic axis was statistically significant between right eyes and left eyes after 6 months. These changes and differences may require long-term follow-up and further investigation.
Astigmatism ; Axis, Cervical Vertebra ; Follow-Up Studies ; Humans ; Keratomileusis, Laser In Situ* ; Myopia

PURPOSE: To obtain normal values of positive wave (b-wave) in the multifocal ERG in terms of age and sex of Koreans. METHODS: The multifocal ERGs by using RETIscan visual evoked response imaging system were tested for 80 eyes. 61 retinal locations were stimulated concurrently. We analyzed the average responses of 5 concentric rings. RESULTS: In the amplitudes of b-wave, ring 1, 84.1 5.4 nV/deg, was the largest of all the other rings and ring 5, 23.1+/-1.5 nV/deg, was the smallest of all the other rings (P<0.05). No statistically significant difference was observed in amplitude between sexs. The implicit time of b-wave was the longest in the ring 1, 40.8 1.6 ms, and shortest in the ring 4, 36.7+/-0.9 ms (P<0.05). CONCLUSIONS: The amplitude of b-wave was the largest in the fovea, and became smaller with eccentricity. The largest amplitude of b-wave was observed in the age of twenties. The amplitude of b-wave was decreased with age in the ring 3, 4, and 5. The interindividual variation of the amplitude of b-wave was greatest in the fovea. The implicit time of b-wave in the fovea was the longest, and that in the ring 4 was the shortest. It became longer from the ring 5, again.
Electroretinography* ; Evoked Potentials, Visual ; Reference Values* ; Retinaldehyde

PURPOSE: To report a case of multiple sclerosis showing homonymous hemianopia which is rare in multiple sclerosis. METHODS: A 6-year-old male patient presented with headache and seizure. A brain MRI demonstrated multiple high signal lesions along subcortical white matter of both cerebral hemispheres. A visual field examination demonstrated left homonymous hemianopia. Visual field defect was improved after intravenous steroid theraphy. RESULTS: Multiple sclerosis is rare under age ten, and homonymous hemianopia also rarely occurs in multiple sclerosis.
Brain ; Cerebrum ; Child* ; Headache ; Hemianopsia* ; Humans ; Magnetic Resonance Imaging ; Male ; Multiple Sclerosis* ; Optic Neuritis ; Seizures ; Visual Fields

The purpose of this study is to evaluate the extent of peroxynitrite generation in the pool of radicals/oxidants from intraocular inflammation using luminol-dependent chemiluminescence(LDCL)method. S-antigen induced uveitis was produced in Lewis rats. The rats were killed at the peak of inflammation, and the retinas and choroids were collected for the LDCL. Sodium bicarbonate was used to confirm the peroxynitrite signal. Superoxide dismutase(SOD), N-nitro-L-arginine methyl ester(LNAME)and aminoguanidine(AG)were tried to evaluate the inhibitory effect of superoxide and nitric oxide. LDCL counts for 6 inflamed and 6 control retina/choroid preparations were 66, 429+/-413 cpm and 13, 941+/-105 cpm, respectively(p<0.01). In the presence of bicarbonate, emission was increased by 125.3+/-6.6%(n=6)and the signal was sustained for 2 hours. SOD, L-NAME and AG suppressed the LDCL by 39.8+/-6.1%(n=3), 20.4+/-4.4%(n=3) and 35.9+/-4.0 %(n=3), These observations suggest that peroxynitrite contributes considerably to the generation of the total pool of reactive species by the cellular infiltrate. The presence of a high level of peroxynitrite, a potent oxidizing and nitrating agent, in inflamed retina may cause irreversible tissue damage to the photoreceptors.
Animals ; Choroid ; Inflammation ; Luminescence* ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Peroxynitrous Acid ; Rats ; Retina ; Sodium Bicarbonate ; Superoxides ; Uveitis*

PURPOSE: We report a 32-year-old man with DeMorsier syndrome, who was referred for seizures, esotropia and visual disturbance of left eye. METHODS: Fundus examination, visual field examination and the visual evoked potential were performed, and other diagnostic studies included endocrine determinations, the electroencephalogram and MR imaging. RESULTS: Ophthalmic examination revealed left optic nerve hypoplasia with the "double ring" sign. Axial MR T1 weighted image showed tiny left optic nerve and absence of the septum pellucidum. Subsequent evaluation revealed temporal visual field defect, abnormal VEP and deuteranomaly of left eye.
Adult ; Amblyopia* ; Electroencephalography ; Esotropia ; Evoked Potentials, Visual ; Humans ; Magnetic Resonance Imaging ; Optic Nerve ; Seizures ; Septum Pellucidum ; Visual Fields

PURPOSE: Demonstrate unequivocally the generation of nitric oxide in experimental autoimmune uveoretinitis by electron spin resonance spectroscopy (ESR) using ferrous iron complex of N-methyl-D-glucamine dithiocarbamate, (MGD)2-Fe2+, as a spin trap. METHODS: Experimental autoimmune uveitis was induced in Lewis rats, and at the peak of the intraocular inflammation, the animals received intravitreous injections of the spin trap. The retina and choroid dissected from the enucleated globes were subjected to ESR. Similarly, the retina and choroid obtained at the peak of experimental autoimmune uveo-retinitis (EAU) were placed in a vial containing luminal, and chemiluminescence was counted on a Packard liquid scintillation analyzer. RESULTS: The ESR three-line spectrum (g=2.04; a(N)=12.5 G) obtained was characteristic of the adduct [(MGD)2-Fe2+-NO]. The majority of this signal was eliminated by the inducible nitric oxide synthase (iNOS) specific inhibitor aminoguanidine injected inflamed retina was detected when compared with that of the non inflamed controls. The chemiluminescent activity was further increased two-fold by the addition of bicarbonate to the inflamed retina; the phenomenon is attributable only to the presence of a high steady-state concentration of peroxynitrite. CONCLUSIONS: The study shows an unequivocal presence of nitric oxide in EAU retina and choroid and the generation of peroxynitrite. High levels of these reactive nitrogen species generated in the inflamed retina and choroids are certain to cause irreversible tissue damage, especially at the susceptible sites such as photoreceptors.
Uveitis/immunology/*metabolism ; Thiocarbamates ; Spin Trapping ; Spin Labels ; Sorbitol/analogs & derivatives ; Retina/metabolism ; Reactive Nitrogen Species/*metabolism ; Rats, Inbred Lew ; Rats ; Peptide Fragments/immunology ; Humans ; Electron Spin Resonance Spectroscopy ; Choroid/metabolism ; Autoimmune Diseases/immunology/*metabolism ; Arrestin/immunology ; Animals

PURPOSE: Ticlopidine, which has platelet inhibitory property, is currently used in peripheral arterial obstructive disease, ischemic stroke, and coronary artery disease. It is also known to have antiangiogenesis effect. We studied the effect of ticlopidine on rabbit corneal angiogenesis induced by VEGF. METHODS: In control group, a hydron pellet containing 300ng VEGF and phosphate buffered saline(PBS) was implanted intrastromally in the superior cornea. In treatment group, a hydron pellet containing 300ng VEGF and 375micro gram ticlopidine was implanted as the same manner. At 3, 5, and 7 day after implantation, we examined corneas under the microscope and estimated the angiogenesis score. RESULTS: At 5 and 7 day after implantation, ticlopidine-treated group had mean angiogenesis score of 27.9 and 49.1(p=0.014, independent t-test), while control group scored 13.0 and 25.3(p=0.004). CONCLUSIONS: In a rabbit corneal pocket assay, ticlopidine appears to have inhibitory effect on VEGF-induced corneal angiogenesis.
Angiogenesis Inhibitors ; Arterial Occlusive Diseases ; Blood Platelets ; Cornea ; Corneal Neovascularization* ; Coronary Artery Disease ; Stroke ; Ticlopidine* ; Vascular Endothelial Growth Factor A*

PURPOSE: To determine the natural history and clinical characteristics of keratitis associated with measles which is currently epidemic in Korea. METHODS: Eighty-four hospitalized patients with measles were prospectively examined between December 2000 and March 2001, during their admission period. Ocular and adnexal examination was performed with a slit lamp biomicroscope. Fundus examination and corneal sensitivity test were also performed. RESULTS: The age and sex distributions were not significant. Age of patients ranged from 18 months to 19 years. All patients with measles have conjunctivitis signs, such as follicles and injection. Superficial keratitis was detected in 7 of 84 patients (8.3%). Corneal lesions were bilateral, well demarcated, round, multiple and 0.2 to 0.4 mm in size. The mean duration of keratitis was 10.1+/-2.9 days in this study. All keratitis resolved spontaneously using artificial tears and prophylactic antibiotic eyedrops CONCLUSIONS:Keratitis associated with measles developed frequently (8.3%), so careful ophthalmic examination should be performed in measles.
Conjunctivitis ; Humans ; Keratitis* ; Korea ; Measles* ; Natural History ; Ophthalmic Solutions ; Prospective Studies ; Sex Distribution