In the process of closing scleral wounds caused by various conditions, incarceration of conjunctiva, Tenon's capsule, or vitreous in the wound can occur unexpectedly. We created such conditions experimentally in order to discover their intraocular complications. The experimental materials consisted of 12 albino rabbits (24 eyes) divided into two groups (Groups I & II). Vitrectomy was performed in the Group I rabbits (12 eyes) but not in the Group II rabbits (12 eyes). Flaps of conjunctiva and Tenon's capsule were made and inserted into the vitreous cavity through the sclerotomy site, which was soon closed. Fundal examination of the rabbits was carried out using an indirect ophthalmoscope at intervals after the procedure; first at 3 days, then at 1, 3, and 6 weeks, and then at 3 months and 6 months, respectively. Enucleation of the rabbits' eyes 4 from two different rabbits at each of these intervals was carried out, and the extracted eyes were examined under a light microscope at each interval. The results are summarized as follows: 1. All rabbit eyes studied showed intraocular fibrovascular proliferation. 2. The extent of tissue proliferation, which was proportional to the amount of vitreous hemorrhage, was greater in Group II than in Group I. 3. The proliferated tissue developed to "band" by three weeks postexperiment, after which it gradually regressed. 4. The fibrovascular band was made of fibroblasts, stromal matrix, and capillaries.
Animals ; Cell Division ; Conjunctiva/pathology ; Eye Injuries/surgery ; Fundus Oculi ; Postoperative Complications ; Rabbits ; Retinal Diseases/pathology ; Retinal Vessels/*pathology ; Sclera/*surgery ; Vitrectomy ; Vitreous Hemorrhage/pathology

In the process of closing a scleral wound caused by various conditions, incarceration af the conjunctiva, Tenon's capsule or vitreous in the wound can occur unexpectedly. We created such conditions experimentally to determine their intraocular complications. The experimental, materials were 12 albino rabhits(24 eyes) and the rabbits were divided into two groups(I and II). Group I rabbits(12 eyes) received no vinectormy and group II rabbits(12 eyes) received a vitrectormy. After the conjunctiva and Tenon's capsule flap was made, the tissue flap was inserted into the vitreous cavity through the sclerotomy site- Fundus examination with an indirect ophthalmoscope and enucleation for histology were performed at 3 days, 1 week, 3 weeks, 6 weeks, 3 months and 6 months after the experiment. The results were as follows: 1, Intraocular fibrovascular proliferation developed in all experimental rabbit eyes. 2. The more vitreous hemorrhage developed, the greater was the fibrovascular proliferation and the degree of fibrovascular proliferation was more marked in group II than group I. 3. The fibrovascular proliferation developed to a band in 3 weeks, then regressed gradually. 4. The fibrovascular band was composed of fibroblasts, stromal matrix and few vessels.
Conjunctiva ; Fibroblasts ; Ophthalmoscopes ; Rabbits ; Tenon Capsule ; Vitreous Hemorrhage ; Wounds and Injuries*

In the process of closing a scleral wound caused by various conditions, incarceration af the conjunctiva, Tenon's capsule or vitreous in the wound can occur unexpectedly. We created such conditions experimentally to determine their intraocular complications. The experimental, materials were 12 albino rabhits(24 eyes) and the rabbits were divided into two groups(I and II). Group I rabbits(12 eyes) received no vinectormy and group II rabbits(12 eyes) received a vitrectormy. After the conjunctiva and Tenon's capsule flap was made, the tissue flap was inserted into the vitreous cavity through the sclerotomy site- Fundus examination with an indirect ophthalmoscope and enucleation for histology were performed at 3 days, 1 week, 3 weeks, 6 weeks, 3 months and 6 months after the experiment. The results were as follows: 1, Intraocular fibrovascular proliferation developed in all experimental rabbit eyes. 2. The more vitreous hemorrhage developed, the greater was the fibrovascular proliferation and the degree of fibrovascular proliferation was more marked in group II than group I. 3. The fibrovascular proliferation developed to a band in 3 weeks, then regressed gradually. 4. The fibrovascular band was composed of fibroblasts, stromal matrix and few vessels.
Conjunctiva ; Fibroblasts ; Ophthalmoscopes ; Rabbits ; Tenon Capsule ; Vitreous Hemorrhage ; Wounds and Injuries*

Forty three eyes with vitreous hemorrhage caused by branch retinal vein occlusion had been underwent pars plana vitrectomy and followed-up over 6 months. The eyes were classified into 4 groups according to intraoperative fundus findings-group 1; vitreous hemorrhage only, group 2; vitreous hemorrhage with fibrovascular proliferation, group 3; vitreous hemorrhage with traction retinal detachments, group 4; vitreous hemorrhage with rhegmatogenous retinal detachments. Analysis was focused on the clinical characteristics and postoperative outcome in each group. The durations of vitreous hemorrhage were longer significantly in group 2 and group 3. The vision improved postoperatively in 35 of 43 eyes(81.3%). The percentage of postoperative visual improvements was 100%(18 of 18 eyes) in group 1, 85.7%(12 of 14 eyes) in group 2, 66.6%(4 of 6 eyes) in group 3, and 20$(1 of 5 eyes) in group 4. The preoperative ultrasono-graphic findings of retinal status were accorded with intraoperative retinal findings in 74.4% of eyes.
Retinal Detachment ; Retinal Vein Occlusion* ; Retinal Vein* ; Retinaldehyde* ; Traction ; Ultrasonography ; Vitrectomy ; Vitreous Hemorrhage*

The visual results of laser photocoagulation for subfoveal choroidal neovascular membrane (CNVM) has not always been satisfactory. The surgical removal of the neovascular membrane may be another treatment option. To investigate the prognosis and risk factors of this surgery, we analyzed the results of surgical removal of subfoveal CNVM (23 eyes), subfoveal hemorrhage with CNVM (6 eyes), and subfoveal hemorrhage alone (6 eyes). The mean follow-up period was 17.7 months (range 2 to 47 months). The mean preoperative membrane size was 0.89 disc diameter and the mean postoperative retinal pigment epithelial (RPE) defect size was 1.33 disc diameter. Visual improvement was observed in 13 out of the 23 eyes (56.5%) with sufoveal CNVM, four out of the six eyes (66.6%) with subretinal hemorrhage and CNVM, and five out of the six eyes (83.3%) with subretinal hemorrhage only. The visual outcome of subfoveal CNVM surgery was related to the presence of a subfoveal RPE defect (p = 0.005) rather than to the size of the RPE defect. No recurrence of neovascular membrane was observed during the follow up period. In conclusion, surgical removal may be a good alternative treatment for subfoveal CNVM.
Choroidal Neovascularization/surgery* ; Choroidal Neovascularization/diagnosis ; Choroidal Neovascularization/complications ; Comparative Study ; Female ; Fluorescein Angiography ; Fovea Centralis/surgery ; Fovea Centralis/pathology ; Fundus Oculi ; Human ; Laser Coagulation* ; Male ; Middle Age ; Pigment Epithelium of Eye/pathology ; Prognosis ; Retinal Hemorrhage/surgery ; Retinal Hemorrhage/diagnosis ; Retinal Hemorrhage/complications ; Retrospective Studies ; Risk Factors ; Visual Acuity

The purpose of this study was to evaluate the usefulness of retinal nerve fiber layer [RNFL] photography and Heidelberg Retina Tomograph [HRT, Heidelberg, Germany] in early detection of glaucoma. Among 2802 people who underwent routine health checkup at. Seoul National University Hospital from July I to Decernber 31, 1996, forty-nine persons were included whose IOP was above 21mmHg or cup/disc ratio was 0.5 or greater. RNFL photography, HRT and automated perimetry [Humphrey Field Analyzer, program C30-2] were performed. Twelve eyes were diagnosed as glaucoma and one sye as glaucoma suspect. Four eyes with glaucoma had RNFL defect with normal visual field and 7 eyes with glaucoma had both RNFL defect and glaucomatous visual field defect. Of 26 eyes suggested as glaucoma by FSM classification of HRT, only 8 eyes met the diagnostic cri-teria of glaucoma of this study. Among 21 eyes with decreased hump height in HRT only 7 eyes were diagnosed as glaucoma. RNFL photography increased the detection rate for glaucoma by 50% over that with visual field test. only. RNFL photography will be a valuable method for early detection of glaucorna while HRT may play a suppleinentary role.
Classification ; Glaucoma* ; Humans ; Nerve Fibers* ; Photography ; Retina ; Retinaldehyde* ; Seoul ; Visual Field Tests ; Visual Fields

To establish animal model of exudative retinal detachment in Sprague Dawley albino rats and to elucidate the possible role of retinal vein in the induction of exudative retinal detachments, rose bengal photosensitive dye was injected intravenously and argon laser was applied. In group A(10 eyes), laser was applied on intervascular retinal areas linearly. In group B (12 eyes), laser was applied on major retinal veins. In group C(4 eyes), laser was applied on major retinal arteris. In group D(3 eyes), laser was applied on major retinal veins without rose bengal dye and in group E(26 eyes), only the rose bengal dye was perfused. And in group F(3 eyes), normal eyes were fixed for negative controls. Exudative bullous retinal detachment occurred only in group B and these resutls were confirmed in histological examinations. In control groups (D and E), tissue injuries were not found. In conclusion, exudative retinal detachment could be induced by occlusion of retinal veins in albino rats and the abnormalities of retinal venous blood flow were required for the induction of exudative retinal detachment.
Animals ; Argon ; Models, Animal ; Rats* ; Retinal Detachment* ; Retinal Vein ; Retinaldehyde* ; Rose Bengal

The relationship between the amount of posterior displacement of the retinal surface at the temporal disc margin and the reference height(HRef)in analyzing optic disc using Heidelberg Retina Tomograph(HRT;Heidelberg Engineering, Heidelberg, Germany)was evaluated. The displacement was measured as mean height of contour(MHC)in the temporal 40degrees C segment(20degrees C superior and 20degrees C inferior to the horizontal midline)of optic disc. HRef is a value representing the location of the standard reference plane. The accordances of HRef and stereometric parameters between right and left disc were also evaluated. MHC in the temporal 40 degrees C and nasal 40 degrees C segment, HRef, and stereometric parameters of optic disc were measured with the HRT in 244 eyes of 122 subjects. HRef was 0.376+/-0.099 mm in the right disc and 0.385+/-0.090 mm in the left disc. There was good correlation between HRef and MHC in the temporal 40degrees C segment(r=0.97, p<0.01), but poor in the nasal 40 degrees C segment(r=0.29, p<0.01). The accordances of HRef and stereometric parameters increased as the difference of MHC in the temporal 40degrees C segment between right and left disc decreased. HRef was affected by the amount of posterior displacement of the retinal surface at the temporal disc margin, which occurs in instances such as a tilted disc. We should find the method to adjust stereometric parameters to the amount of disc tilt.
Retina* ; Retinaldehyde*

Purpose: . The purpose of the study was to fabricate a prototype robotic simulator for dental education, to test whether it could simulate mandibular movements, and to assess the possibility of the stimulator responding to stimuli during dental practice. Materials and methods: . A virtual simulator model was developed based on segmentation of the hard tissues using cone-beam computed tomography (CBCT) data. The simulator frame was 3D printed using polylactic acid (PLA) material, and dentiforms and silicone face skin were also inserted. Servo actuators were used to control the movements of the simulator, and the simulator’s response to dental stimuli was created by pressure and water level sensors.A water level test was performed to determine the specific threshold of the water level sensor. The mandibular movements and mandibular range of motion of the simulator were tested through computer simulation and the actual model. Results: . The prototype robotic simulator consisted of an operational unit, an upper body with an electric device, a head with a temporomandibular joint (TMJ) and dentiforms. The TMJ of the simulator was capable of driving two degrees of freedom, implementing rotational and translational movements. In the water level test, the specific threshold of the water level sensor was 10.35 ml. The mandibular range of motion of the simulator was 50 mm in both computer simulation and the actual model. Conclusion . Although further advancements are still required to improve its efficiency and stability, the upper-body prototype simulator has the potential to be useful in dental practice education.