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*

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

The acute retinal necrosis is characterized by necrotizing retinitis, vitritis, and retinal vasculitis occurring in otherwise healthy patients. It develops into retinal necrosis and detachment. The clinical course of ARN is rapidly progressive despite therapeutic efforts. We experienced 6 eyes of 5 cases with ARN. In this study, the distribution of patients was 3 males and 2 females and they were from 23 to 53 years old in age, average 39.4 years. The duration of observation was from 3 days to 24 months and we observed retinal detachment in 2 cases(40%) that developed 2 weeks and 4 weeks after onset in each cases. One case involved both eyes, and the other, in one eye. Four of 6 eyes(65%) had a final visual acuity of less than 0.1.
Female ; Humans ; Male ; Middle Aged ; Necrosis ; Retinal Detachment ; Retinal Necrosis Syndrome, Acute* ; Retinal Vasculitis ; Retinaldehyde ; Retinitis ; Visual Acuity

The measurement of the rate of flow of aqueous humor is very important for the investigation of the physiology in the aqueous humor and maintenance of the intraocular pressure. Argon laser trabeculoplasty apears to be effective in lowering intraocular pressure with much advantage over standard filtering operation but despite the, widespread use of argon laser traheculoplasty in medically unresponsive open angle glaucoma, the exact mechanism by which it reduce outflow resistance remains unknown and so the study of the mechanism and the most suitable site are required due to the associated complication and less effectiveness during long term evaluation. We studied the changes in the rate of constant, the rate of flow for 2 weeks, intraocular pressure and C-value for 4 weeks, histopathologic changes for 36 days after argon laser trabeculoplasty in 25 rabbits(21 white and 4 black). The normal control group of 20 rabbits was also measured for intraocular pressure and C-value and the rate of constant, the rate of flow. In trabeculoplasty, we used the Britt 900 argon laser photocoagulator(pulse wave) with 50~60 burns at a setting of 700~800 mW, 0.2 seconds duration, 50 micro beam diameter in 360 degrees portion at the site between scleral spur and trabecularmeshwork. The results were as follows; 1) In control group of 20 rabbits. 1. The mean normal intraocular pressure was 18.5 +/- 2.0mmHg. 2. The mean normal C-value was 0.385 +/- 0.072 cumm/min/mmHg. 3. The mean normal rate of constant was 0.0114 +/- 0.0021min(-1). 4. The mean normal rate of flow was 3.980 +/- 0.735 micro l/min. 5. The relationship between rate of flow and C-value was high. 2) In rabbits after argon laser trabeculoplasty. 1. The white and black rabbits showed a statistically significant decrease of intraocular pressure for 4 weeks and elevation of rate of flow for 2 weeks after argon laser trabeculoplasty (p<0.001). 2. The changes of post-laser intraocular pressure was related with changes of C-value after argon laser trabeculoplasty for 4 weeks. 3. The changes of the mean IOP and C-value for post-laser 4 weeks showed no significant differences between white group and black group. 4. In histopathologic changes for 36 days, inflammtory change was not seen for post-laser period, fibrosis and edema in trabecular meshwork was more prominent at the 8th day, edema and fibrosis was regressed as normal at the post-laser 27th day.
Aqueous Humor* ; Argon* ; Burns ; Edema ; Fibrosis ; Glaucoma, Open-Angle ; Intraocular Pressure ; Physiology ; Rabbits* ; Trabecular Meshwork ; Trabeculectomy*

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*

In the condition of diabetic retinopathy, the vascular changes are localized primarily in the retinal capillaries and are presumed to promote angiogenesis. To investigate the change of retinal blood flow velocities and morphological parameters in diabetic retinopathy, we measured perifoveal capillary blood velocities(v) and the size of foveal avascular zones(FAZ). Thirteen patients with diabetic maculopathy and nine healthy volunteers were included in this study. The scanning laser technique in conjunction with an image analysing system were used to assess the morphological and hemodynamic changes in diabetic retinopathy. Diabetic maculopathy group showed a slower capillary blood velocity than normal group(2.44+/-0.39mm/sec vs2.75+/-0.61 mm/sec, p>0.18). The foveal avascular zone was significantly larger in diabetic maculopathy group than in normal group(313.5+/-64.6micrometervs. 238.9+/-93.8micrometer, p<0.05). This results indicate that the retinal microcirculation is altered in diabetic patients compared with healthy subjects. These alterations may be due to the change of the capillary wall and blood viscosity in diabetic patients. The determination of these parameters can be utilized in monitoring the progress of diabetic maculopathy.
Blood Flow Velocity ; Blood Viscosity ; Capillaries ; Diabetic Retinopathy ; Healthy Volunteers ; Hemodynamics ; Humans ; Microcirculation ; Retinaldehyde

Pattern-reversal retinal potentials(PRRP) are electrical signals generated within retina, possibly by the retinal ganglion cells, when a phase-alternating check board pattern is viewed. Authors clinically studied the characteristics of PRRP the mean amplitude and latency with 24 minute checks, the effect of the spatial frequency, the effect of defocusing and the retinocortical time in 20 normals, using Nicolet CA 1,000. The results are as follows; 1. The mean latency P1 and the mean P1-N2 amplitude of PRRP in normal group was 39.19 +/- 3.30(msec), 1.32 +/- 0.22(uV), respectively. 2. The mean retinocortical time in normal group was 52.93 +/- 7.39(msec). 3. The P1-N2 amplitude of PRRP was reduced linearly with increasing defocusing, and significant amplitude reduction was observed when defocusing amounted to +1D. 4. When central 3 degree of stimulus was covered in order to simulate a macular pathology, PRRP to 24 minute checks was abnormal both in amplitude and latency. 5. Peak response amplitude of PRRP was obtained with large checksizes(3 degrees 12 minutes, 6 degrees 24 minutes).
Pathology ; Retina ; Retinal Ganglion Cells ; Retinaldehyde*

The primary purpose of the study is to investigate the destruction and recovery of the blood retinal barrier after photocoagulation and cryotherapy in the rabbits. The 110 pigmented rabbits were used in this experiment. After photocagulation and cryotherapy we injected intravenousely a dose of 25 mg/kg of fluorescein sodium, and then sampled blood and vitreous and measured the concentration of fluorescein sodium by means of High Performance Liquid Chromatography. The calculated penetration ratio which indicates the destruction of the blood retinal barrier is obtained by dividing fluorescein sodium concentration of vitreous by integral of fluorescein sodium concentration of the plasma from 3 min to 60 min. Subsequently, fundus photography and enucleation for flat preparation were performed in each experimental rabbit. The fluorescein concentration of vitreous of the normal rabbit is 3.60 +/- 4.75 X 10(-9)gm/ml and its penetration ratio is 0.20 +/- 0.23 X 10(-6) min. After measuring the correlation between the frequency of photocoagulation and penetration ratio and between the frequency of cryotherapy and penetration ratio, we found out that the correlation coefficient was 0.885 and 0.909 respectively. And this experiment showed that penetration ratio was higher in cryotherapy group than in photocoagulation group. In addition, we divided these experimental animals into 4 groups, mild and severe cryotherapy groups and lighter and heaver photocoagulation groups, and assessed the penetration ratio of these four groups at 1,3,7,14,28, and 42 days after treatment. As a result, penetration ratio was highest at 3 days after treatment and was almost back to normal by 42 days in all experimental groups except in severe cryotherapy group. Compared with photocagulation groups, cryotherapy groups showed more extensive destruction and delayed recovery of the blood retinal barrier. In fundus photography, in the photocoagulation groups white patch was developed after treatment, at 7 days white patches disappeared and were replaced by pigmented and scarred tissue; by 42 days the margin of these lesions was indistinct and the lesions were changed into relatively small scarred patches. On the other hand, in the cryotherapy groups the thick round white patch wasdeveloped after treament, at 7 days large round white patches disappeared and were replaced by pigmented and scarred tissue; by 42 days the lesions were replaced by large scarred patches with pigmentation and depigmentation. In flat preparation, in the photocoagulation groups central necrotic zone and intermediate zone with hyperpigmentation and peripheral zone with hypopigmentation was presented at 1 day. In the cryotherapy groups the diminished density, in the center and white ring at the margin was revealed at 1 day. From 7 days in photocogulation groups and from 14 days in the cryotherapy groups, retinal pigment epithelium began to show proliferation and by 42 days, retinal pigment epithelial layer of both groups except severe cryotherapy group was replaced by relatively normal retinal pigment epithelium.
Animals ; Blood-Retinal Barrier* ; Chromatography, Liquid ; Cicatrix ; Cryotherapy* ; Fluorescein ; Hand ; Hyperpigmentation ; Hypopigmentation ; Light Coagulation* ; Photography ; Pigmentation ; Plasma ; Rabbits* ; Retinal Pigment Epithelium ; Retinaldehyde