No Abstract Available.
Retinal Detachment* ; Retinaldehyde*

PURPOSE: To evaluate the relation between recovery of visual function and microperimetric fixation area in eyes with idiophthic macular hole after vitrectomy. METHODS: We used SLO (Scanning laser microscope, Rodenstock, Germany) microperimetry to examine foveal retinal function and fixation area in 14 eyes with idiopathic macular hole following pars plana vitrectomy. The relation between those preoperative and postoperative best corrected visual acuity and fixation area was studied. RESULTS: The macular hole size was correlated with preoperative visual acuity (p=0.026) and the closure of hole was related to the size of fixation area (p=0.003). The postoperative visual acuity was related to symptom duration before the vitrectomy (p=0.03), but not related to preoperative macular hole size. The fixation area correlated with the postoperative best corected visual acuity (p=0.043) and the direction of movement was variable. In most eyes, fixation area was located above the horizontal meridian. CONCLUSIONS: The fixation area was correlated with postoperative visual acuity and we think functional macular hole closure as well as anatomical closure were useful parameter of the success of macular hole surgery.
Ophthalmoscopes* ; Retinal Perforations* ; Retinaldehyde ; Visual Acuity ; Vitrectomy*

Proliferative vitreoretinopathy (PVR) is a main cause of failure in retinal reattachment surgery. There have been many studies about the inhibition of proliferative vitreoretinophthy with several drugs. Authors investigated the inhibitory effect of proliferative vitreoretinopathy and retinal toxicity with various concentration of daunorubicin after intravitreal injection into the eyes of the pigmented rabbit. 7 pigment rabbit (11eyes) were used as subjects. After lensectomy and vitrectomy, control group was injected dermal fibroblast and F-BSS, and treatment group was injected dermal fibroblast and 5, 10, 15, 30 nmol Daunorubicin. At two weeks after intravitreal injection, both group were enucleated and examined with gross finding, light--microscopy, and electronmicroscopy. In all control group, proliferative vitreoretinopathy was found, but only preretinal membrane formation was found in 5, 10 nmol Daunorubicin injected group. In 15 nmol Daunorubicin injected group, the retina structure was preserved normally. In 30 nmol Daunorubicin injected group, the retinal outer segment was degenerated in microscopic finding. These results show that Daunorubicin has a potent effect on proliferative vitreoretinopathy, especially in 15 nmol, but retinal toxicity is suspected in marethan 30 nmol.
Daunorubicin* ; Fibroblasts ; Intravitreal Injections ; Membranes ; Retina ; Retinal Photoreceptor Cell Outer Segment ; Retinaldehyde ; Vitrectomy ; Vitreoretinopathy, Proliferative*

Electrical conductivity of eyeball replaced with vitreous substitutes were also measured in both the non-enucleated and enucleated eye. The study of correlation between the electroretinogram and conductivity of eyeball to be replaced with vitreous substitutes was also evaluated. The electrical conductivity of each vitreous replacement was shown 74.5% in vitreous, 77.5% in saline, 100% in air and silicone oil respectively relative to standard material -1.5 battery, 100%. There was no difference of conductivity between the enucleated eye and non-enucleated eye. There were no correlation between the ERG amplitude and conductivity. As a result of experiments, the decrease in amplitude is suggested as a damage of retina by manipulation and surgery rather than decrease of conductivity with vitreous replacements.
Electric Conductivity* ; Rabbits* ; Retina ; Silicone Oils

PURPOSE: There were many studies on the distributions of the retinal ganglion cells(RGC) in the experimental model of the retinal ischemia. RGC was known to be more sensitive to the ischemic injury than the other types of the retinal cells. So, we would identify the changes of the retinal ganglion cell morphologies and distribution after the iatrogenic retinal ischemia induced by intraocular pressure(IOP) elevation. METHODS: Eight pigmented and six white rabbits were used and retinal ischemia was induced by increasing IOP higher than 120 mmHg for 60 minutes. Electroretinogram were recorded at 6 days or 13 days, and histologic findings were observed at 7 or 14 days. RESULTS: After 7 days, RGC densities decreased, cytoplasmic staining disappeared, and the intranuclear hyperpigmentation was noted. RGC densities decreased significantly at 14 days. In the vertical retinal section, some flattening of retinal ganglion cell layer and inner plexiform layer was observed. Changes in the cellular morphologies were prominent. CONCLUSIONS: It may be more appropriate to examine both the retinal whole-mount and the vertical tissue section for the estimatation of the changes of retinal ganglion cell layer in the pressure-induced retinal ischemia.
Cytoplasm ; Ganglion Cysts* ; Hyperpigmentation ; Ischemia ; Models, Theoretical ; Rabbits ; Retina* ; Retinal Ganglion Cells ; Retinaldehyde*

The effect of 0.25% and 0.5% Timolol on intraocular pressure and concentration in aqueous humor was studied after topical instillation in the white rabbit. The intraocular pressure was measured with pneuma tonometer and the Timolol concentration in aqueous humor was measured with High Preformance Liquid Chromatograph after fine needle aspiration of aqueous humor at various time intervals. The results were as follows; 1. The percentage reduction of intraocular pressure increased with time and reached a peak after 3 hours. 2. The concentration of Timolol in aqueous humor increased with time and reached a peak after 3 hours. 3. There was close correlation between intraocular pressure and Timolol concentration in aqueous humor.
Aqueous Humor* ; Biopsy, Fine-Needle ; Intraocular Pressure* ; Timolol*

The purpose of this paper is to investigate the extent of destruction Blood-ocularbarrier between colored rabbits and white rabbits after photocoagulation, as preliminary experiment for the using colored and white rabbits. A total of 10 rabbits (5 white rabbits, 5 colored rabbits) were used. Photocoagulation in the right eye of 5 white rabbits and 5 colored rabbits were performed. The left eye of all the rabbits was control eye and the right eye was laser treated eye. After 3 days, a dose of 25mg/kg of 10% fluorescein sodium was injected in the ear vein of rabbit intravenously. We sampled aquous humor in anterior chamber and vitreous, and checked fluorescein concentration in anterior chamber and vitreous using HPLC (High Performance Liquid Chromatography). The results obtained were as follows; In experimental animals, 1. There is no significance between colored rabbits and white rabbits in fluorescein concentration of vitreous and aquous humor in control group. 2. The concentration of the fluorescein in the anterior chamber and vitreous of the right photocoagulated eye was higher than control eye, but there is no significance between colored rabbits and white rabbits. 3. there is no significance between colored rabbits and white rabbits in extent of destruction of Blood-ocular-barrier after Laser photocoagulation.
Animals ; Anterior Chamber ; Chromatography, High Pressure Liquid ; Ear ; Fluorescein ; Light Coagulation ; Rabbits* ; Veins

PURPOSE: We compared the clinicopathologic effects of TTT between pigmented and albino rabbits. METHODS: TTT was delivered using infrared diode laser at 810 nm(Iris Medical Instrument, Mountain Veiw, CA, USA) and applied with spot size of 3 mm, duration of 60 seconds. At 1 week and 4 weeks after TTT, fundus photographs and simultaneous FAG/ICG angiogram were taken with SLO(Scanning Laser Ophthalmolscopy, Rodenstock, Munish, Germany). Light and electron microscopic examination were performed. RESULTS: In pigmented rabbits, visible funduscopic change was visible even with minimal power setting(100 mW). Obliteration of choroidal vessels was observed on ICG angiogram. In microscopic examination, entire layers of neural retina, retinal pigment epithelial cells, and deep choroid were severely damaged at the center of treated fields. Whereas, in albino rabbits fundus changes were not observed at any power setting. However, focal thrombosis at margin of lesion was identified on ICG angiogram after power of 300 mW. In microscopic examination, tissue damage was developed up to 600 mW and the lesion extended into the superficial choroid posteriorly and outer neural retina anterioly. CONCLUSIONS: The effect of TTT was increased with fundus pigmentation. Clinically we should adjust TTT power setting according to the amount of melanin pigmentation in the fundus.
Choroid ; Epithelial Cells ; Lasers, Semiconductor ; Melanins ; Pigmentation ; Rabbits ; Retina* ; Retinaldehyde ; Thrombosis

Dexamethasone sodium phosphate (DSP) is increasingly used in the treatment of ocular inflammatory diseases by systemic, periocular, and recently, intravitreal injection. We have developed a method for the determination of vitreous levels of DSP by reverse phase HPLC. In this method, co-elution of vitreous proteins with DSP is resolved by a prior sample clean-up procedure using Waters Sep-Pak C18 cartridge; the protein is separated and eluted with water while DSP, paraben and prednisone are eluted with methanol. DSP in the resulting sample is then separated by reverse phase HPLC and quantified by UV absorption at 254 nm. The recovery of DSP through the sample clean-up is 68.9 +/- 3.0%. DSP quantitation is linear from 0.1 mg to 1.0 mg per 1.0 ml vitreous. This method provides a simple, sensitive and reliable technique for determining the vitreous levels of DSP.
Animals ; Anti-Inflammatory Agents/*analysis ; Chromatography, High Pressure Liquid/*methods ; Dexamethasone/*analogs & derivatives/analysis ; Rabbits ; Reproducibility of Results ; Sensitivity and Specificity ; Vitreous Body/*chemistry

Although many risk factors were reported, the exact pathogenesis of diabetic retinopathy is still unknown. The platelet derived growth factor(PDGF) is released from platelet alpha granule and plays a major role in wound repair, embryogenesis, and the pathogenesis of artherosclerosis. To evaluate whether serum PDGF may be a risk factors for the development of vascular complications of diabetes mellitus, we reviewed 36 diabetic patients from June 1996 to March 1997. The serum PDGF level was higher in the group of proliferative diabetic retinopathy(23.49+/-23.77pg/ml) and the control group(23.74+/-16.26pg/ml) than in nonproliferative diabetic retinopathy group(19.19+/-18.21pg/ml). The difference was not statistically significant. Patients who had a history of vitrectomy or laser treatment for proliferative diabetic retinopathy had higher serum PDGF level than those with no treatment. We conclude that the PDGF may play a role as one of the risk factors in diabetic retinopathy or their growth factors, and however further study will be required to elucidate the influence of PDGF on the couse of diabetic retinopathy.
Blood Platelets ; Diabetes Complications ; Diabetic Retinopathy ; Embryonic Development ; Female ; Humans ; Intercellular Signaling Peptides and Proteins ; Plasma* ; Platelet-Derived Growth Factor ; Pregnancy ; Risk Factors* ; Vitrectomy ; Wounds and Injuries