We have attempted to measure parafoveal retinal acuity directly on the exact retinal locus, while observing the retinal image in real time using the scanning laser ophthalmoscope(SLO 101, Rodenstock, Munish, Germany). By the SLO Visumetry software(Rodenstock v. 3.0), thirty eyes of healthy volunteers were examined in 20degrees image field. Using Snellen E as stimulus, the examination was performed from the fovea by the radial pattern. The maximal retinal distance point, which responded to stimulus, was recorded by the pixel, and the distance(mm) from the fovea was calculated by the Bennett formula. The maximum distance from the fovea at the given stimulus size was achieved as follows: 0.32+/-0.01mmat the 15 x15 arc of minute(0.333), 0.63+/-0.01mm at the 17 x17 arc of minute(0.294), 1.05+/-0.03 mmat 20 x 20 arc of minute(0.25), and 1.44+/-0.0 5 mmat the 23 x23 arc of minute(0.217). It was also revealed that the horizontal maximal distance from fovea at given stimulus size was statistically superior to the vertical maximal distance(p<0.05). In conclusion we were able to establish the normal range of parafoveal retinal acuity in healthy volunteers. It may serve as the baseline for subsequent study of retinal pathology and functional evaluation as well as its treatment.
Healthy Volunteers* ; Pathology ; Reference Values ; Retinaldehyde* ; Visual Acuity*

No abstract available.
Pericardial Effusion* ; Radionuclide Imaging* ; Technetium Tc 99m Medronate*

The function of ascorbic acid in the eye is unknown. It acts mainly as antioxidant, protecting ocular tissue from oxygen free radical released by light. The concentration of ascorbic acid in the aqueous humor of diurnal mammals is considerably higher than its concentration in the plasma. But the exact concentration of ascorbic acid in the vitreous is unknown. We determined the ascorbic acid concentration in serum, aqueous humor and vitreous of the rabbit using High Performance Liquid Chromatography. The concentration of ascorbic acid is 146.8+/-78.0microgram/ml in aqueous humor, and 58.2+/-25.8microgram/ml(R=0.992) in vitreous. There was significant correlation betweenthe concentration of ascorbic acid in the aqueous humor and vitreous from the same eye. And the inter-indivudual difference of ascorbic acid concntration is greater than the inter-cular difference of ascorbic acid concentration. Therefore it probably due to an active secretion and diffusion into posteror aqueous & vitrous.
Aqueous Humor ; Ascorbic Acid* ; Chromatography, Liquid ; Diffusion ; Mammals ; Oxygen ; Plasma ; Vitreous Body*

Perfluorodecalin, which is one of the perfluorocarbon liquids, is not established safety in use of long-acting intraocular tamponade. Therefore, to determine its safety we injected it alone and combined with silicone oil into the vitreous of vitrectomized eyes. We evaluated the changes of the fundus, electroretinogram, histopathology as light and electron microgragh after lensectomy and vitrectomy in pigmented rabbits periodically. In rabbits replaced with perfluorodecalin alone, fundus showed mild proliferative vitreoretinopathy and micrographs showed the destruction of the inner and outer segments of the photoreceptors. In rabbits replaced with perfluorodecalin and silicone oil, fundus showed more severe proliferative vitreoretinopathy than perfluorodecalin alone and micrographs showed the destruction of the entire retina. In electroretinogram, the amplitude was decreased markedly. So, it is considered that perfluorodecalin was not tolerant in case of longacting intraocular tamponade and also perfluorodecalin combined with silicone oil developed severe proliferative vitreoretinopathy.
Rabbits ; Retina ; Silicone Oils* ; Vitrectomy ; Vitreoretinopathy, Proliferative

To study the isolation and purification and proliferation of the cell in cell culture system, and to develop an improved culture method by a modified cell isolation technique and modified culture medium. The RPE cells were cultured in 3 different mediums: type I(MEM medium with 20% FCS) type II(F-10 medium with 20% FCS) and type III(DMEM medium with 10% FCS, EGF, hydrocortisone, insulin, ethanolamine, phosphoethanolamine, chorea toxin, triiodotyronine, adenine, transferrin and BPE). We compared population doubling(P.D.), population doubling time(P.D.T), morphologic changes and phagocytic activity during a 7week period. Rapid proliferation and high purity of retinal pigment epithelial cells(RPE cells) showed in type III culture medium. Type III culture medium presented the best results in P.D., P.D.T. and cell purification. In type III culture medium, single RPE cells produced about 6 X 10(7) RPE cells in the 7week period and morphology and phagocytic activity were well maintained, when UV-B irradiation at RPE was used to produce melanin, it had no effect, but the RPE cell was inhibited by UV-B irradiation. This improved culture method for RPE cells will provide a good in-vitro model for the studies of biochemistry, cellular function of the RPE cell, as well as its clinical application in eye disease.
Adenine ; Biochemistry ; Cell Culture Techniques ; Cell Separation ; Chorea ; Epidermal Growth Factor ; Epithelial Cells* ; Ethanolamine ; Eye Diseases ; Hydrocortisone ; Insulin ; Melanins ; Retinaldehyde* ; Transferrin

Perfluorocarbon liquids(PFCL) have been used as an intraoperative tool for repair of complicated retinal detachment with improving surgical results. However, little is known about the potential toxic effect of PFCL that remain in the eye after surgery to anterior segment tissue. In this study we evaluated the effect of this substance on the corneal tissue. Eight rabbits underwent injection of 50 micro l of perfluorodecalin in the anterior chamber of the right eyes. The left eyes were injected with the same amount of balanced salt solution(BSS) as a control. The clinical appearance of the eyes were recorded at three days, one week and two weeks after injection, and histological examination was done two weeks after injection. The differences of intraocular pressure(IOP) between the right and left eyes were not statistically significant at three days, one week and two weeks after injection, and all of right eyes showed inferior bulbar counctival injection for same periods. In the histological examination of cornea exposed to PFCL, the number and the height of endothelial cells were reduced and decreased, respectively. These findings suggested that PFCL may have a toxic effect on the corneal endothelial cells.
Anterior Chamber ; Cornea ; Endothelial Cells ; Rabbits ; Retinal Detachment

Inspite of technical advances, the need for pharmacologic treatment of proliferative vitreoretinopathy was increased. In order to evaluate the antiproliferative effect of various antimetabolites to the rabbit retinal pigment epithelial cell, we treated cultured rabbit retinal pigment epithelial cell with different concentration of drugs to perform dose inhibition studies. We found that the antimetabolites inhibited the proliferation of rabbit retinal pigment epithelial cell in a dose dependent and a time dependent manner. The drug concentration required for 50% inhibition of cell growth (ID50) were found to be as follows (BCNU; 6.51 mg/L, 5-FU ; 8.94 mg/L, Daunorubicin; 0.03mg/L, Mitomycin-C; 0.26mg/L).
Antimetabolites* ; Daunorubicin ; Epithelial Cells* ; Fluorouracil ; Mitomycin ; Retinaldehyde* ; Vitreoretinopathy, Proliferative

The purpose of this study was to standardize normal EOG values in Koreans. The subject were 23 normal Koreans varying in age 16-40 yrs with no ocular abnormality or disease. EOG was recorded by Life-Tech instrument Model 7310 ERG/EOG stimulator, Model 7101 ERG/EOG analyzer. The result were as follows. Dark trough potential was 235.65 +/- 71.59 uV, Light Peak Potential was 402.60 +/- 103.09 uV, EOG ratio(Lp/Dt) was 1.74 +/- 0.23, Dark trough time was 14-15 minutes, and light peak time was 10 minutes.
Electrooculography

Bacterial endophthalmitis is an ocular emergency that requires rapid diagnosis and therapeutic decision making. The introdection of intravitreal injection of antibiotics has been a major advancement because it has resulted in a marked improvement in visual outcome. The intravitreal injection of steroids may be potentially useful in the treatment of endophthalmitis and other ocular inflammatory diseases. Forty eyes of pigmented rabbits were used, and divided into two groups. Group I was eyes without vitrectomy. In the right eye, 100 microliter of 1mgvancomycin, 400 microliter amikacin and 400 microliter dexamethasone injected was done. Group II was eyes with vitrectomy and lensectomy. At 2 weeks after lens and vitreous removal, rabbit eyes received an injection of a combination of 1mg vancomycin, 400 microliter amikacin and 400 microliter dexamethasone in right eye and BSS in left eye. The effect of combination injection was examined by light and transmission, scanning electron microscope at 3 days, 1 week, 2 weeks and 6 weeks following injection. The injection of combination without vitrectomy produced no toxicity. After injections of either combination or BSS after vitrectomy, macrophages were observed on the surface of retinal pigment epithelium and disorganized outer segments. This finding seems to be produced by vitrectomy procedure rather than drug toxicity. These results supports the hypothesis that the injection of these combinations is not toxic to aphakic/vitrectomized eyes.
Amikacin ; Anti-Bacterial Agents ; Decision Making ; Dexamethasone* ; Diagnosis ; Drug-Related Side Effects and Adverse Reactions ; Emergencies ; Endophthalmitis ; Intravitreal Injections ; Macrophages ; Rabbits ; Retinal Pigment Epithelium ; Steroids ; Vancomycin ; Vitrectomy*

The purpose of this study is to investigate the minimal toxic dose of sodium iodate after the intravenous injection in the pigmented rabbits. Thirteen rabbits were given a intravenous injection of 2% sodium iodate(pH 7.4). The animals were devided into two groups, the 10mg/kg and 25mg/kginjected groups. In ERG findings, the b wave amplitude decreased one week after injection in both groups and was recovered at 5 weeks in the 10mg/kg-injected group, but it was not recovered upto 5 weeks in the 25mg/kg-injected group. In the electron microscopic findings, the abnormal change was not observed in the 10mg/kg-injected group but the pigment epithelium and outer segments of the photoreceptors were markedly destroyed and did not recovered upon the 5 weeks in the 25mg/kg-injected group. Therefore, ultrastructural and functional changes occurred in a 25mg/kg of sodium iodate injected group and those changes were not recovered for the period of 5 weeks after injection.
Animals ; Epithelium ; Injections, Intravenous ; Microscopy, Electron ; Rabbits ; Retinal Pigment Epithelium ; Sodium*