ObjectiveTo investigate the medium and long-term influence of silicon oil versus heavy silicone oil on rabbit retinas. Methods28 health standard rabbits were randomly divided into A, B and C groups, with 12, 12 and 4 rabbits respectively. All rabbits received routine vitrectomy and tamponade with silicone oil (group A), or heavy silicone oil (group B) or balanced salt solution (group C). After 4, 8, 12 and 24 weeks, the retinal b-wave amplitude was measured by ERG, posterior retinal thickness was measured by optical coherence tomography (OCT). Retinal ultrastructure and tissue morphology were observed by transmission electron microscopy and optical microscopy. ResultsCompare to group C, the b-wave amplitude decreased at 4 weeks after surgery, and decreased at 8 weeks after surgery for group B, and decreased at 8 weeks after surgery, and decreased at 24 weeks after surgery for group A. The decreases were greater in group B than group A at 8, 12, 24 weeks after surgery, the difference was statistically significant (P < 0.05). The posterior retinal thickness of group A and B was thinner than group C at 24 weeks after surgery (P < 0.05). The decreases were greater in group B than group A, the difference was statistically significant (P < 0.05). Transmission electron microscopy and optical microscopy revealed severe pathological changes of retinal ultrastructure and morphology in group A and B rabbit eyes, at 12 weeks and 8 weeks after surgery respectively. The changes were more severe in group B and group A, including edema and necrosis in cone/rod cells, in disk membranes, mitochondria, cytoplasm, nucleus and other organelles. The morphological changes were also more severe in group B and group A, including degenerations of ganglion cell layer, inner nuclear layer changes. Those changes became more severe when the tamponade time extended. ConclusionThe heavy silicone influence on visual function, ultrastructures, histomorphology of rabbit retinas is much worse than the silicon oil, and the effect is more significant with its time prolong.
PURPOSE:To evaluate the ability Of retinoic acid(RA) in silicon oil(SiO)to inhibit the proliferation of injected intraocular fibroblast cells. METHODS:Thirty New Zealand white rabbits (58 eyes)were divided into three groups. In control group ,only SiO(10 eyes)or BSS(10 eyes)were injected intravitreally and 5mu;g/ml (18 eyes)or 10mu;g/ml (20 eyes)RA in SiO were injected into other lwo groups respectively. Three days after gas-compression vitrectomy, 2 times;105 fibroblasts and Sio(0.5ml)or BSS(0.5ml)were injected in all eyes sequentially.The morbidity of tractional retinal detachment (TRD) were observed by ophthalmoscope until 4 weeks. RESULTS:After 4 weeks,in control ,5mu;g/ml RA in SiO and 10mu;g/ml RA in SiO group,80. 00%,44.44%,and 30.00% eyes developed TRD respectively. Significant statistical differences were found between the control group and the two treated groups (P＜0.05). CONCLUSIONS:5mu;g/ml or 10mu;g/ml RA in SiO can inhibit the occurrence of TRD effectively. （Chin J Ocul Fundus Dis,1997,13:174-176）
ObjectiveTo investigate the potential effect of hyperopia status on subfoveal choroidal thickness (SFCT) in silicone oil (SO)-filled eyes.MethodsThis self-comparative study was conducted in Department of Ophthalmology, Central Theater Command General Hospital. The 50 patients (100 eyes) were collected with unilateral macula-on rhegmatogenous retinal detachment from January 2019 to July 2019, who successfully underwent pars plana vitrectomy (PPV) and SO tamponade. Retinal reattachment was observed after surgery in all patients. One month after PPV, the affected eye was wore soft, contact lenses for 24 hours to correct refractive error (RE), depending on its optometry value. The SFCT of the affected eyes was measured using OCT before and after lenses wear. The fellow eyes also received OCT examination at the same time. T test was used to compare SFCT between SO-filled eyes and fellow eyes.ResultsThe mean RE of the SO-filled eyes was +6.38±1.12 D. The mean SFCT of SO-filled eyes (247.12±17.63 μm) was significantly thinner than that of the fellow eyes (276.32.55±17.63 μm) (P＜0.001). The SFCT of the SO-filled eyes was significantly thinner than fellow eyes, and the difference was statistically significant (t=－3.95, P＜0.001). After lenses wear, the mean SFCT of the SO-filled eyes increased to 276.32±24.86 μm. Compared with before lenses wear, the difference was statistically significant (t=－4.30, P＜0.001). Compared with the fellow eye, the difference was not statistically significant (t=0.05, P＞0.05).ConclusionSFCT reduction in the SO-filled eyes may be due to the hyperopia status caused by SO, which can be reserved by RE correction.
Objective To establish and evaluate a hydrocephalus model in dogs. Methods Twelve healthy adult male mongrel dogs (weight, 10-15 kg) were randomly divided into the control group (n=6) and the experimental group (n=6). All the dogs were given CT and neurological examination to exclude congenital ventricular enlargement and neurological abnormity before they received hydrocephalus induction. Surgical procedures included the exposing of the foramen magnum area, the opening of the atlantooccipita anadesma, and the injecting of silicone oil (0.3 ml/kg) into the fourth ventricle through a silicone tube. Normal saline was injected in the control group. The Tarlov neurological fitness assessment and the Evan’s ratio were used to evaluatethe degree of hydrocephalus at 3, 14 and 56 days after operation. Results In the experimental group, the dogs were dull and unsteady in walking,and they drank and ate less. The lateral ventricle began to expand 3 days afteroperation, and then the temple horn of the lateral ventricle and the third ventricle were also affected 14 days after operation. The ventricles were enlarged progressively after operation. The Tarlov scores measured at 3, 14 and 56 days afteroperation had a significant difference at the same time point between the control group(5.83±0.75，6.50±0.55，6.00±0.63) and the experimental group (4.00±0.89，4.83±1.17，4.50±1.05，P＜0.01), but had no significant difference within the same group at different time points (P＞0.05). The Evan’s ratios measured at 3, 14 and 56 days after operation were 0.33±0.04,0.39±006，0.44±0.03，respectively,in the experimental group; and were 0.27±0.06，0.25±0.09, 0.26±0.05,respectively,in the control group. There was a significant difference atthe same time point between the two groups, and at different time points within the experimental group (P＜0.05).Conclusion The dog model of hydrocephalus induced by the injecting of silicone oil into the fourth ventricle has a highsuccess rate, and the model is appropriate for the studies on diagnosis and therapy of hydrocephalus.
Objective To investigate the time and the mechanism of the toxic and side effects of silicone oil on ocular tissues. Methods 19 human eyeballs were examined histopathologically at different time intervals after silicone oil tamponade. Results Microscopic bubbles presumably containing silicone oil were found in sensory retina,RPE,optic nerve, pre and subretinal membrane,iris,anterior chamber angle,and retrocorneal membrane.In the eyes containing silicone oil for less than 9 months.Silicone bubbles were present only in the surface of retina(within preretinal membrane or macrophages),and after that time,silicone bubbles were noted within sensory retina.In an eye enucleated 39 months after intravitreal silicone tamponade,the parenchyma and subarachnoid space of the optic nerve were found to be diffusely invaded by silicone bubbles. Conclusion The histopathologic changes of ocular tissues are related to the duration of intravitreal silicone oil tamponade. (Chin J Ocul Fundus Dis, 1999, 15: 232-234)
OBJECTIVE:To evaluate the toxicity of retinoic acid in silicone oil to the retinal tissue. METHOD:Twelve New Zealand white rabbits(24 eyes)were divided into three grorps at random. Three days after gas-compression vitrectomy,24 eyes were unedrgone gas/silicone oil exchange. The silicone oil 0.5 ml was injected intravitreally in 4 eyes as controls ,and 5mu;g/ml retinoic acid silicone oil 0.5ml in 10 eyes and 10 mu;g/ml retinoic acid silicone oil 0.5 ml in 10 eyes respectively as 2 study groups. After intravitrea[ injections, all the eyes were examined by ophthalmoscopy on the 1st, 3rd, 7th, 14th, 21st and 28th day. The retinas of the enucleated eyes on the 28th day were then examined by light microscopy and transmission electrone microscopy. RESULT: No evidence of toxicity was found in retinas after intravitreal injections of silicone oil with 5 mu;g/ml or 10 mu;g/ml retinoic acid. CONCLUSION :There was no toxic effect on the retinas by using 5 mu;g/ml or 10 mu;g/ml retinoic acid in intravitreal silicone oil tamponade operation. （Chin J Ocul Fundus Dis,1997,13: 81-82）
OBJECTIVE:To investigate the treatment of retinal redetachment after vitrectomy and silicone oil tamponade. METHODS:Investigating retrospectively on the treatment effect of 8 cases of redetachment of retina with proliferative vitreoretinopathy(PVR) in which the retinas had been attached formerly after vetrectomy and silicone oil tamponade operation.The reoperative procedures included pars plana vitrectomy,membranes peeling,retinotomy,inner exchange of the fluid and silicone oil tampnade and subretinal membranes were removed out in 2 eyes. RESULTS:Six eyes had anatomical reattachment postoperatively and another 2 eyes still had inferior shallow retinal detachment.Visual acuity was improved in 6 patients and remained unchange in 2 patients. CONCLUSIONS:The cause of recurrent retinal detachment might be the formation of the proliferative epiretinal and subretinal membranes,and vitrectomy to release the traction of proliferative membranes and full fluid silicone oil exchange should do good to reattachment. （Chin J Ocul Fundus Dis,1996,12: 13-15 ）
Objective To observe the therapeutic effect of combined surgery of anterior and posterior segment and silicon oil tamponade on macular hole retinal detachment in eyes with high myopia.Methods The clinical data of 48 high myopia patients (48 eyes) with macular hole retinal detachment were retrospectively analyzed. Retinal detachment was mainly at the posterior pole; macular hole was confirmed by noncontact Hruby lens and optical coherence tomography (OCT). Phacoemulsification combined with pars plana vitrectomy and silicon oil tamponade were performed to all patients, of which 41 had undergone internal limiting membrane peeling, and 23 had intraocular lens implanting. The oil had been removed 3.5-48.0 months after the first surgery and OCT had been performed before the removal. The followup period after the removal of the silicon oil was more than 1 year.Results The edge of the macular hole could not be seen under the noncontact Hruby lens 1 week after the surgery in all but 5 patients, and the visual acuity improved. The silicon oil had been removed in all of the 48 patients; the OCT scan before the removal showed that the closed macular holes can be in U shape (8 eyes), V shape (6 eyes) or W shape (23 eyes). About 1338 months after the oil removal, retinal detachment recurred in 2 patients with the Wshaped holes. At the end of the followup period, 16 patients (33.3%) had U or Vshaped macular holes, and 32 patients (66.7%) had Wshaped macular holes. The rate of retinal reattachment was 100%.Conclusion Combined surgery of anterior and posterior segment and silicon oil tamponade is effective on macular hole retinal detachment in eyes with high myopia.