An experimental model of rhegmatogenous retinal detachment (RRD) in rabbits was established to simulate the pathophysiologic condition of human RRD. 24 rabbits were randomly divided into 3 groups and underwent vitrectomy with a vitrector and/or retinotomy with a Charles flute needle, with 12 in group I (vitrectomy and retinotomy), 7 in group I (retinotomy) and 5 in group III (vitrectomy). All animals underwent follow-up examinations with direct and indirect ophthalmoscopy and fundus photography 12 h and day 1, 3, 5, 7, 10, 14, 21, and 28 after the procedure(s). Retinal changes were recorded. As a result, 10 RRDs were successfully established in group I. Direct and indirect ophthalmoscopy and fundus photography demonstrated typical features of RRD. No RRD developed in group II and III. It was concluded that the experimental rhegmatogenous retinal detachment produced in a rabbit model after vitrectomy with retinotomy in this study was a convenient and reliable one. This RRD model mimicked the typical pathophysiological changes in humans.
*Disease Models, Animal ; Random Allocation ; Retina/surgery ; *Retinal Detachment ; Vitrectomy

Mitomycin-C(MMC) has been increasingly used as adjunct chemotherapy during glaucoma filtering surgery in order to increase the success rate, because of its ability to inhibit the proliferation of fibroblast. Although MMC demonstrates toxic effects in the anterior segment of the eye, few studies on its retinal toxicity have been reported. Therefore, this study was performed to investigate the retinal toxicity of MMC in the rabbit after intra cameral irrigation. After anesthesia, 1 ml of MMC(40 mg/ml) was intracamerally irrigated in right eye and 1ml of balanced salt solution(BSS) was used as control in the left eye. The electroretinogram was checked before, 2 and 7 days after intracameral MMC irrigation. The fundus examination and histopathology by light microscopy and transmission electron microscopy were performed at 7days after MMC irrigation. On electroretinogram, scotopic b-wave amplitude in MMC irrigated eye was significantly decreased 7 days after irrigation as compared with BSS irrigated eye. The retina in MMC irrigated eye was normal on the fundus findings and histopathology by light microscopy and transmission electron microscopy 7 days after irrigation. This findings suggest that intracameral irrigation of MMC may induce the functional disturbance rather than structural alteration of retina.
Anesthesia ; Drug Therapy ; Fibroblasts ; Filtering Surgery ; Glaucoma ; Microscopy ; Microscopy, Electron, Transmission ; Mitomycin* ; Retina ; Retinaldehyde

We reviewed the records of 23 patients who underwent repeat operation after initial vitreoretinal surgery in Chungnam National University Hospital between January 1993 and December 1993. Of 193 eyes who underwent vitreoretinal surgery in that period, 23(12%) had undergone reoperation. The most common cause of initial anatomic failure and reoperation was either new or recurrent proliferative vitreoretinopathy(10 eyes). Other causes included iatrogenic retinal tears(5 eyes), hidden retinal breaks(4 eyes), vitreous traction(1 eye), inappropriate chorioretinal adhesion(1 eye), and new break(1 eye). We performed vitreous base dissection on all 9 eyes with anterior proliferative vitreoretinopathy. With additional surgery and after a mean follow-up period of 10.4 months, 21(91%) of 23 retinas were reattached. The final cause of anatomic failure was anterior proliferative vitreoretinopathy. Of the 23 reoperated eyes, 20(87%) had postoperative visual acuity of 0.05 or better.
Chungcheongnam-do ; Follow-Up Studies ; Humans ; Reoperation ; Retina ; Retinaldehyde ; Visual Acuity ; Vitreoretinal Surgery* ; Vitreoretinopathy, Proliferative

Experimental total retinectomy was performed in pigmented rabbit eyes to in vestigate its long-term effects on the operated and nonoperated opposite eyes from both clinical and histological aspects. There was no significant change in intraocular pressure between the preoperative and postoperative measurements during the six months after surgery. Rubeosis iridis, intraocular hemorrhage and phthisis bulbi were not evident in the operated and opposite eyes. Light microscopic examination revealed congestion of the choroidial vessels. There were scattered areas of retinal pigment epithelial cell proliferation. Transmission electron microscopic examination showed apiral mounding of the retinal pigment epithelium. Apical processes were short and reduced in number. Apical processes of the retinal pigment epithelial cells interdigitated with surface processes of the proliferating retinal pigment epithelial cells. There were numerous melanosomes in the cytoplasm of the proliferating retinal pigment epithelial cells. Cell junctions between the retinal pigment epithelial cells were well preserved.
Animals ; Intraocular Pressure ; Longitudinal Studies ; Pigment Epithelium of Eye/ultrastructure ; Prognosis ; Rabbits ; Retina/*surgery

Proliferative vitreoretinopathy is the principal cause of failure in rhegmatogenous retinal detachment surgery. The final cause of anatomic failure is anterior proliferative vitreoretinopathy. Surgical outcome of anterior proliferative vitreoretinopathy is poorer than that of posterior proliferative vitreoretinopathy. Of 147 cases which underwent vitreoretinal surgery from January through December 1993, 16 eyes(l6 patients) had anterior proliferative vitreoretinopathy. Seven eyes had anterior proliferative vitreoretinopathy at initial surgery(group 1). Remaining 9 eyes developed anterior proliferative vitreoretinopathy after primary vitrectomy(group 2). Of 16 eyes, 3 were aphakic, 2 were pseudophakic, and remaining 11 were phakic. Lens was removed in 11 phakic eyes. Meticulous vitreous base dissection and removal of anterior epiretinal membrane were performed. After minimal follow-up of 6 months, retina reattached in 11 eyes(69%) including all nine eyes of group 2. Nine eyes(56%) had postoperative visual acuity of 0.025 or better. These results suggest that both vitreous base dissection and meticulous removal of anterior and posterior epiretinal membrane should be crucial in improving surgical success rate of anterior proliferative vitreoretinopathy.
Epiretinal Membrane ; Follow-Up Studies ; Retina ; Retinal Detachment ; Visual Acuity ; Vitreoretinal Surgery ; Vitreoretinopathy, Proliferative*

An experimental model of rhegmatogenous retinal detachment (RRD) in rabbits was established to simulate the pathophysiologic condition of human RRD. 24 rabbits were randomly divided into 3 groups and underwent vitrectomy with a vitrector and/or retinotomy with a Charles flute needle, with 12 in group I (vitrectomy and retinotomy), 7 in group I (retinotomy) and 5 in group III (vitrectomy). All animals underwent follow-up examinations with direct and indirect ophthalmoscopy and fundus photography 12 h and day 1, 3, 5, 7, 10, 14, 21, and 28 after the procedure(s). Retinal changes were recorded. As a result, 10 RRDs were successfully established in group I. Direct and indirect ophthalmoscopy and fundus photography demonstrated typical features of RRD. No RRD developed in group II and III. It was concluded that the experimental rhegmatogenous retinal detachment produced in a rabbit model after vitrectomy with retinotomy in this study was a convenient and reliable one. This RRD model mimicked the typical pathophysiological changes in humans.
Animals ; Disease Models, Animal ; Rabbits ; Random Allocation ; Retina ; surgery ; Retinal Detachment ; Vitrectomy

We studied the ultrastructural features of four consecutive subfoveal neovascularmembranes (SFNM) associated with age-related macular degeneration. Cellular components of the membranes included retinal pigment epithelial (RPE) cells, endothelium-lined vascular channels, macrophages, myofibroblasts, fibrocytes, glial cells, erythrocytes, and lymphocytes. Extracellular interstitial constituents included collagen fibrils, basal laminar deposits, fibrin and young elastic fibrils. These findings show that SFNMs consist of various cells originating from surrounding tissues and vessels. Among these RPE cells and macrophages are the main cellular components and in conjunction with various extracellular matrix, especially collagen, may play an important role in the formation and maintenance of the membranes.
Basement Membrane/surgery/ultrastructure ; Humans ; Macular Degeneration/complications ; Microscopy, Electron ; Retina/*ultrastructure ; Retinal Neovascularization/etiology/*pathology/surgery

Aged ; Diabetic Retinopathy ; physiopathology ; surgery ; Electroretinography ; Female ; Humans ; Macular Edema ; physiopathology ; surgery ; Male ; Middle Aged ; Retina ; physiopathology ; Visual Acuity ; Vitrectomy

This report presents the effectiveness of 25-gauge Transconjunctival Sutureless Vitrectomy (TSV) for various vitreoretinal disorders. We performed vitreoretinal surgery on 6 patients using 25-gauge TSV. Minimal or no leakage of intraocular fluid or gas was observed at the entry site. No case required a suture to close the conjunctival or scleral opening site, and no complications resulted from the opening site. Median preoperative visual acuity was 0.04 and median postoperative best corrected visual acuity (BCVA) with a mean follow-up of 12 weeks, was 0.45. Median preoperative intraocular pressure was 12.67mmHg, and median intraocular pressure on the first postoperative day was 15.67 mmHg. Because transconjunctival sutureless surgery is minimally invasive, it increases the efficiency of vitrectomy, hastens postoperative recovery, and improves outcomes due to the simplified surgical procedure. We feel that the adoption of the 25-gauge TSV would lead to improved patient comfort, care, and management.
Adult ; Aged ; Child, Preschool ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Retina/*surgery ; Retinal Diseases/*surgery ; Retrospective Studies ; Visual Acuity ; Vitrectomy/*instrumentation/*methods ; Vitreous Body/*surgery

PURPOSE: To report the clinical features, clinical course, and treatment outcomes after laser photocoagulation in infants with aggressive posterior retinopathy of prematurity (APROP) and capillary-free zones in vascularized retina. METHODS: Six patients (12 eyes) with APROP and capillary-free zones in vascularized retina were retrospectively reviewed. Twelve eyes of six infants were included and were treated with laser photocoagulation for avascular retina and for capillary-free zones in vascularized retina, except for the posterior pole, and fundus findings were photographically-documented in sequence. In addition, anatomic and visual outcomes were evaluated with complications of APROP. RESULTS: Among all of the consecutive infants with APROP, capillary-free zones in vascularized retina were demonstrated in 24% of the infants. All of the infants were >27 weeks of gestation age and had birth weights >1,000 g. After laser treatment, 7 eyes (58.3%) had favorable outcomes, and late capillary filling in capillary-free zones of vascularized retina were noted, however 4 eyes (33.3%) progressed to retinal detachment and 1 eye (8.3%) was complicated by a retinal fold-distorting posterior pole. The visual outcomes were associated with anatomic outcomes. CONCLUSIONS: The anatomic outcomes in infants with APROP who had capillary-free zones were comparable to previously reported infants with APROP. The late capillary filling of capillary-free zones in vascularized retina was noted, and angiogenesis was considered to be involved. This process toward normal capillary formation or neovascularization in APROP, might determine its outcome.
Capillaries/*pathology ; Female ; Humans ; Infant ; Laser Coagulation/*methods ; Male ; Retina/*pathology/surgery ; Retinal Vessels/*pathology/surgery ; Retinopathy of Prematurity/*pathology/*surgery ; Retrospective Studies ; Treatment Outcome