The Results of Nation-Wide Registry of Age-related Macular Degeneration in Korea

PURPOSE: To evaluate the incidence and clinical features of age-related macular degeneration (AMD) in Korea. METHODS: Web-based (www.armd-nova.or.kr) registration was conducted for AMD patients aged 50 or more who were newly diagnosed by retinal specialists in Korea from August 20, 2005 to August 20, 2006. Patient data including ophthalmologic examination, fundus photography, fluorescein angiogram and/or indocyanin green angiogram (ICG), past medical history, behavioral habit, combined systemic diseases were up-loaded. RESULTS: Among finally enrolled 1,141 newly diagnosed AMD patients, 690 patients (60.5%) were male and 451 patients (39.5%) were female. The average age of AMD patients was 69.7+/-8.0. Early AMD was observed in 190 patients and 951 patients had late AMD. Classic choroidal neovascular membrane (CNVM) was observed in 18.6% of exudative AMD patients and 63.4 % had occult CNVM. Subfoveal CNVM was observed in 80.4% of the patients with CNVM. Among the 580 exudative AMD eyes that performed indocyanin green angiography (ICG), 184 eyes (31.7%) had polypoidal choroidal vasculopathy (PCV) and 36 eyes (6.2%) showed retinal angiomatous proliferation (RAP). Age, male gender, smoking, diabetes and hypertension significantly increased the risk of the AMD among Koreans. CONCLUSIONS: Because of the low rate of participation by retinal specialists, definite incidence of AMD was not obtainable. However, the estimated 1-year AMD incidence in the Pusan area of Korea is at least 0.4%. In contrast to Western people, 31.7% of exudative AMD cases were revealed to be PCV and 6.2% were revealed to be RAP. This discrepancy between ethnic groups should be considered in the diagnosis and treatment modality selection of Korean AMD patients.

Direct Detection of Reactive Nitrogen Species in Experimental Autoimmune Uveitis

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.

The Inhibitory Effect of Ticlopidine on VEGF Induced Corneal Neovascularization

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.

Normal values of Positive wave in the Multifocal Electroretinography in Korean

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.

A Case of Multiple Sclerosis in Child Showing Homonymous Hemianopia

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.

Prism Diopter for Unconformity between the Optical Center and the Pupil Center

PURPOSE: To investigate the effect of the difference between interoptical and interpupillary center distance on the eye of the patient. METHODS: One hundred patients were enrolled in this study. We investigated the congruities between interpupillary and interoptical center distance, the horizontal balance of optical center, and the induced prismatic effects. RESULTS: Prismatic effects were evaluated for 30 patients who were wearing inaccurate lens centering. The average of P.D in male (64.2+/-2.7 mm) was greater than that in female (61.2+/-2.2 mm). The evolution of the induced horizontal phoria showed that forty-seven percent of the patients had induced exophoria and fifty-three percent of the patients had induced esophoria. The prism diopter of the induced exophoria and esophoria were 0.92+/-0.87delta and 0.62+/-0.46delta, respectively. CONCLUSIONS: When the pupillary distance of or the interpupillary distance was not accurately measured, the prism effect and the induced phoria developed by the difference between interoptical and interpupillary center distance.

Keratitis in Measles

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.

The Change of Tear Flim after laser Epithelial keratomileusis and laser in situ keratomileusis

PURPOSE: To compare the effects of laser epithelial keratomileusis(LASEK) and laser in situ keratomileusis(LASIK) on tear secretion and tear film stability. METHODS: Sixty two eyes went through photorefractive surgery including LASEK(26 eyes, 14 patients) or LASIK(36 eyes, 18 patients) by the same surgeon from January in 2000 to April in 2000. Tear secretion was measured with schirmer test and tear stability was measured with tear breakup time(BUT) preoperatively and 2 months after procedures. RESULTS: In the LASEK group, the preoperative mean values were BUT, 7.46 sec; Shirmer, 11.92 mm, and at postoperative 2 months, they were 6.62 sec and 9.31 mm, respectively. The difference was statistically insignificant(P=0.51, P=0.22). In the LASIK group, the preoperative mean values were BUT, 7.56 sec; Shirmer, 10.56 mm. At 2 months, they were 5.56 sec and 7 mm, respectively. The difference was statistically significant(P=0.02, P=0.02). CONCLUSIONS: Our result showed that tear secretion seemed to be significantly decreased after LASIK, but not after LASEK.

A Case of DeMorsier Syndrome Misdiagnosed as Amblyopia

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.

Factors Affecting the Thickness of Suction Ring in LASIK

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.

Chemiluminescence Study of Pe roxynitrite in Experimental Autoimmune Uveitis

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.

Surgically Induced Astigmatic Change after Laser in Situ Keratomileusis using Manual Microkeratome

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.

Stimulation of macrophage function by interphotoreceptor retinoid-binding protein: production of nitric oxide

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.