Adhesive forces between the retina and the retinal pigment epithelium, which is mainta ined by active mechanisms unique for living animals, deteriorates rapidly after death and leads to spontaneous retinal detachment. Change of retinal adhesiveness in rabbits after death was investigated using a new method. Retinal detachment was induced by applying various levels of aspiration power from 0 to 1OO mmHg to the vitreous cavity using a vitrectomy instrument immediately after the rabbit was killed without enucleation. And the time required for creating the retinal detachment was measured. Retinal adhesiveness deteriorated and spontaneous retinal detachment occurred 28 minutes and 35 seconds after death confirming the active adhesion between the retina and the retinal pigment epithelium before death Increase of aspiration power led to shortening of time required for creating retinal detachment. From aspiration powers of 0 to 100 mmHg, the common logarithm of time required for retinal detachment was inversely proportional to the aspiration power [IogY = 1.45215 - 0.01113X, (R2=0.99041), X: aspiration power (mmHg), Y: time required for creating retinal detachment (minutes)]. Thus, presumed time of retinal detachment could be estimated between the aspiration powers of 0 to 100 mmHg.
Adhesiveness ; Adhesives* ; Animals ; Postmortem Changes* ; Rabbits ; Retina* ; Retinal Detachment ; Retinal Pigment Epithelium* ; Retinaldehyde* ; Vitrectomy

Posterior instability of the shoulder is far less common than anterior or multidirectional instability. There is still controversy in the diagnosis and treatment of recurrent posterior instability, and many treatment protocols have been advocated. However the failure rate as high as 50% was reported. The purpose of this study is to introduce characteristic physical findings of posterior instability, to present our operative techniques, and to report the efficacy of a superior shift of the postero-inferior capsule in the treatment of recurrent posterior instability. From June 1995 to September 1996, five patients, six shoulders underwent postero-inferior capsular shift for posterior instahility and were evaluated at an average of 17 months(ranged from 9 to 26 months) after operation. The average age was 22.4 years. Preoperatively, mean scores of pain, stability and function according to American Shoulder and Elbow Society (ASES) scoring system were 21, 9, and 16 points respectively and mean overall ASES score was 46 points. After surgery, the average range of motion was 175 of forward elevation and 74 of external rotation and internai rotation in back was up to the sixth thoracic level. Postoperative mean scores of pain, stability and function were 29, 34 and 25 points respectively and mean overall ASES score was 88.5 points. No patient had a recurrence of posterior instability. All patients had satisfactory results with significant improvement in stability and function except one case who had multidirectional instability that mainly involved the posterior component
Clinical Protocols ; Diagnosis ; Elbow ; Humans ; Range of Motion, Articular ; Recurrence ; Shoulder*

The early ultrastructural changes of basement membrane thickening and degeneration of the pericyte were noted in retinal capillaries in diabetic patients. However no early ultrastructural changes were reported in diabetic iris capillary. The authors studied the ultrastructural features of basement membrane of iris capillaries which were obtained during cataract surgery in five diabetic patients and compared with those obtained in five nondiabetic patients. The endothelium basal lamina, pericyte basal lamina and membrane-like pericyte matrix in didabetic iris capillaries were thicker than those in nondiabetic Iris capillaries. The thickening of pericyte basal lamina is more prominant than the endothelium basal lamina in diabetes. The duration of diabetes had no relationship to endothelium basal lamina but, showed statistically significant relationship to thickness of pericyte bascal lamina and pericyte matrix.
Basement Membrane* ; Capillaries* ; Cataract ; Endothelium ; Humans ; Iris* ; Pericytes ; Retinaldehyde

The effect of the Nd:YAG laser on the rabbit retina was evaluated with fundus photography, light microscopy and transmission electron microscopy(TEM), and compared with the effect of the Argon laser. Fundus photography was performed at 2 days, 4 days, 7 days, 14 days, 29 days and 49 days after treatment. The enucleated retina was examined by light microscopy and TEM. In YAG treated eye, laser reaction was not found at 0.5mJ level but laser reaction(G2-3) was found at 1.5mJ level. Laser reaction(G3-4) with expulsive bleeding was found at 2.5 and 3.5mJ level. Bleeding was seemed to be originated from the choroidal layer. 2 days after treatment, hemorrhage was sustained but bleeding was not continued. 7 days after treatment, hemorrhage was completely absorbed. In Argon treated eye, photocoagulation burns was well formed without and bleeding. In pathologic examination of YAG treated eye, full thickness disruption of the retina amd Bruch's membrane and replacement of these layers with fibrous scar tissue were revealed at 2.5 and 3.5mJ level. In 1.5mJ energy level of the YAG laser and Argon laser irradiation, the outer half of the retina, RPE and Bruch's membrane appeared to be pridominantely affected than the inner half of the retina. The extent and character of his to pathology in Argon treated lesion was not so different from that of the YAG laser 1.5mJ lesion.
Argon ; Bruch Membrane ; Burns ; Choroid ; Cicatrix ; Hemorrhage ; Lasers, Solid-State ; Light Coagulation ; Microscopy ; Pathology ; Photography ; Retina*

The chronic cyclitis was first described under the designation of cyclitis by Ernst Fuchs in 1892, having been described as peripheral uveitis and pars planitis. The etiopathogenic nature of chronic cyclitis has been in controversy but the role of allergy is suggested in this disease entity, The inflammatory process starts at ciliary body and peripheral chorioretina, extends to anterior chamber and vitreous. It is incidious, bilateral and recurrent, affects young individuals. This condition begins with minimal symptoms of hazy vision and vitreous opacity, may result in serious visual disturbances due to various complications including cataract, macular degeneration, retinal detachment, glaucoma and phthisis bulbi. A 50 year old man was found to have chronic cyclitis in his left eye that was treated with antituberculous agents and sub-Tenon's injection of corticosteroid agent.
Anterior Chamber ; Cataract ; Ciliary Body ; Glaucoma ; Humans ; Hypersensitivity ; Macular Degeneration ; Middle Aged ; Pars Planitis ; Retinal Detachment ; Uveitis* ; Uveitis, Intermediate*

We experienced a case of D3 proliferative vitreoretinopathy complicated with a shortened retina in a 31-year-old male which was managed using 360-degrees circumferential retinotomy technique and a case of D1 proliferative vitreoretinopathy complicated with a shortened retina in a 26-year-old female which was managed using 260-degrees circumferential retinotomy technique. We report these cases with a review of the literature
Adult ; Female ; Humans ; Male ; Retina* ; Vitreoretinopathy, Proliferative

No abstract available.
Appointments and Schedules*

Stargardt's disease is a heredo-macular dystrophy which evidences itself by reduced visual acuity, bilaterally, slowly progressive lesion, and by color blindness starting in youth. The diagnosis of Stargardt's disease is usually made by biomicroscopy and fluoresceine angiography which show many irregular shaped, small yellowish flecks. According to Fishman, the characteristic prolonged time to obtain adequate rod amplitude in dark-adapted electroretionography is advisable for differential diagnosis of Stargardt's disease. We didn't find the abnormal finding of dark-adapted electroretinography in two patients of Stargardt's disease. So, more studies will be needed for electroretinography of Stargardt's disease.
Adolescent ; Angiography ; Color Vision Defects ; Diagnosis ; Diagnosis, Differential ; Electroretinography ; Fluorescein ; Humans ; Visual Acuity

A closed eyeball model was designed to estimate the chorioretinal adhesion of the laser-photocoagulated region. We used it to measure the duration of development of retinal detachment during vitrectomy before and after killing the test rabbits. During testing, negative pressure was applied into the vitreous cavity of the pigmented rabbits. Laser burns were produced in the posterior retina by exposure to an argon blue-green laser beam with a focus diameter of 200 microns of 0.1 to 0.2 second duration and 150 to 250 mW intensity. One hour and one, two, five, seven and fourteen days following laser photocoagulation, vitrectomy was done with a cutting rate of 500 per minute, aspiration pressure of 50 mmHg and infusion pressure of 55.2 mmHg. After core vitrectomy, the rabbit was killed with an intravenous bolus of 100 mg sodium pentobarbital solution. After killing the rabbit, the vitreous cavity was continuously aspirated under the pressure of 25 mmHg while the infusion was stopped. The changes of the fundus, especially development of retinal detachment, were observed in the laser-treated and untreated regions before and after killing the rabbit. When retinal detachment was noted anywhere before killing the rabbit, this postmortem change was not observed. One hour following laser photocoagulation, the laser-treated retina was detached during core vitrectomy before killing the rabbit, and the untreated area was not detached. One day following photocoagulation, the retina was intact before killing the rabbit. After killing the rabbit, the laser-treated retina was detached in four minutes and the untreated retina in 18 minutes postmortem.
Adhesiveness ; Animal ; *Laser Coagulation ; Pigment Epithelium of Eye/*physiology ; Rabbits ; Retina/*physiology ; Retinal Detachment/prevention & control ; Time Factors

The effects of intraocular hypothermia on experimental proliferative vitreoretinopathy in rabbits were studied. Vitrectomy was performed for 30 minutes with irrigating balanced salt solution in rabbit eyes, and the cultured retinal pigment epithelial cells were injected into the vitreous cavity. The irrigating balanced salt solution was used at room temperature in control eyes, and was cooled to 6 degrees C in experimental eyes. Experimental eyes showed less postoperative inflammation and demonstrated less occurrence of tractional retinal detachment compared with the control eyes. In vitro, the growth of cultured human retinal pigment epithelial ceDs was studied in the conditions of different temperatures. Significant suppression of cell growth was noted at 43 degrees C and also at 4 degrees C. The cooled irrigating solution may be used during vitrectomy procedure to decrease the occurrence of proliferative vitreoretinopathy.
Cell Proliferation* ; Epithelial Cells ; Humans ; Hypothermia* ; Inflammation ; Rabbits ; Retinal Detachment ; Retinaldehyde ; Traction ; Vitrectomy ; Vitreoretinopathy, Proliferative