Computer-assisted spectral electroretinography in vitrectomy patients

Computer-assisted spectral electroretinography (CASE), using full field stimulation in the presence of a rod saturating background light, has been found to be a useful means of evaluating retinal function in patients with vitreal opacities. By this means, cone electroretinograms (ERGs) to white as well as spectrally selective stimuli could easily be detected in 22 of 24 eyes with vitreal opacities obscuring any view of the fundus and with minimal or no detectable ERGs to standard single flash stimuli. The responses to spectral stimuli in the presence of a rod saturating background light provides a means of estimating the optical density of the opacity. The results indicate that most patients undergoing vitrectomy for such opacities have considerable superimposed retinal damage and that the opacities themselves are seldom sufficiently dense to decrease the ERG to any great extent. Five eyes studied before and after vitrectomy indicate that successful vitrectomy has no effect on the ERG. The results suggest that CASE may be a useful substitute to the bright flash ERG for evaluating global retinal function behind an opaque media.     

Toxic ocular effects of two fibrinolytic drugs. An experimental electroretinographic study on albino rabbits

The toxic effects on rabbit eyes of 2 intravitreally injected fibrinolytic substances at different concentrations were studied with repeated clinical observations and registrations of the DC ERG. The fellow, control eye of each animal was injected with saline. Urokinase (Ukidan, Serono) (13 rabbits) initially produced aqueous flare (64%), iris hyperaemia (36%) vitreous opacities (27%) and small retinal haemorrhages (18%). 2-3 months after the injection cataract (50%), vitreous opacities (25%) and retinal changes (13%) were observed. The highest dose (10 000 Ploug units) caused reduction of the ERG b-wave, as a sign of retinal toxicity. Tissue activator (D-44, Centre d'immunologie et de biologie Pierre Fabre) (10 rabbits) produced marked aqueous flare (initially 100%, after 2 weeks 50%) and pronounced, persistent vitreous opacities (25% after 2-3 months). At the late stage corneal blood vessels (38%) and cataract (38%) were also found, but only in eyes injected with the highest dose (1000 units), which was retinotoxic as judged by the ERG (reduced b- and c-waves).     

闭合式玻璃体切除术472例分析

本文总结了４７２例４９１眼玻璃体除术的疗效，临床上分为６组，外伤性玻璃体浑浊机化，外伤性玻璃浑浊机化合并视网膜玻璃，眼内异物合并玻璃体混浊机化，眼内异物合并玻璃体浑浊及视网膜脱离，眼内炎及视网膜血管病所致的玻璃体浑浊机化，４９１眼中有３４７眼进行了联合手术，本文对各组的视力结果，手术时机，手术并发症，外伤性视网膜脱离的特点及预后作了分析讨论。     

Ocular toxicity of intravitreal tacrolimus

BACKGROUND AND OBJECTIVE: To investigate the ocular toxicity of intravitreally administered tacrolimus, a drug with potent immunosuppressive activity. METHODS: To evaluate toxicity, tacrolimus was injected into the midvitreous cavity of 20 eyes of New Zealand pigmented rabbits at concentrations of 10, 50, 100, 250, 500, and 1000 microg. Control eyes received balanced salt solution. Eyes receiving 1000 microg were given injections of 0.2 mL solution; all others, including controls, received 0.1 mL. Rabbits were examined before the injections by slit-lamp biomicroscopy, indirect ophthalmoscopy, and an electroretinography test (ERG) was performed. The animals were followed up to 14 days postinjection by clinical examination and ERG. The animals were killed and the eyes were enucleated and processed for light microscopy. RESULTS: No evidence of a retinal toxic reaction was seen in the eyes receiving 10 or 50 microg of tacrolimus. One out of 4 eyes that received 100 microg of the drug developed a vitreous reaction. All eyes treated with 250 microg or more developed vitreous reaction. One eye injected with 1000 microg of the drug developed occlusion of the temporal retinal vessels. Electroretinography showed decreasing b-wave amplitude with both dark- and light-adapted stimulus in the 500 and 1000 microg groups, and it was normal in the other groups. Histopathologic sections showed mild disorganization of the retina only at the 500 and 1000 microg dosage. CONCLUSIONS: Doses of 10 and 50 microg of tacrolimus are nontoxic to rabbit eyes. Only transient vitreous opacities were observed in the groups that received 100 and 250 microg. Intravitreal doses of 500 and 1000 microg of tacrolimus proved to be toxic to the retina.     

纤维蛋白溶解酶和Dispase蛋白酶诱导兔眼玻璃体后脱离的实验研究

目的研究纤维蛋白溶解酶和dispase蛋白酶诱导玻璃体后脱离(PVD)的作用。方法24只健康成年的青紫兰兔随机分为4组,右眼均为实验眼,左眼为对照眼。A组实验眼玻璃体腔内注射纤溶酶1U,B组纤溶酶2 U,C组dispase蛋白酶0.0125U和D组dispase蛋白酶0.025U,对照眼均为眼用平衡盐BSS液0.1 ml。注药前后行眼底镜、裂隙灯和VOLK 90D前置镜以及B超和视网膜电图(ERG)检查,最后取眼球进行光镜、扫描电镜和透射电镜观察。结果电镜结果A组2只实验眼后极部发生不完全性PVD,发生率为33.3%;B、C两组实验眼中各有4只眼发生完全性PVD。发生率为66.7%;D组实验眼有5只眼发生完全性PVD,发生率为83.3%。纤溶酶各组实验眼注药后ERG振幅与术前及对照眼比较无显著性差异(P>0.05),光镜和透射电镜观察视网膜组织结构正常,均未发现明显异常改变。而Dispase蛋白酶各组透射电镜观察视网膜细胞和细胞器出现水肿和变性。ERG检测Dispase两组实验眼术后b波振幅较术前明显降低(P<0.01)。结论玻璃体腔注射纤溶酶2U较注射1U更能有效的诱导PVD且对视网膜无明显的毒性作用。而Dispase蛋白酶虽然可迅速有效的诱导PVD,但对视网膜有明显的毒性作用。     

WHO白内障混浊分级与F—ERG最大反应关系的探讨

目的 观察白内障晶状体混浊对闪光视网膜电流图（F－ERG）最大混合反应（MCR）的影响。方法 对56眼白内障按WHO（1995年）晶状体混浊标准分级;测定其术前和术后3月的MCR;将手术前后F－ERGa,b波振幅差值与晶状体混浊度作对比以评价不同白内障对F－ERG振幅的影响。结果 白内障术后F－ERGa,b波振幅较术前有不同程度增大;核性混浊者手术前后振幅差值较皮质性混浊明显增大（P＜0．01）。结论 混浊晶状体具有光吸收效应并减弱F－ERG反应,核性白内障对MCR振幅的影响较皮质性大,白内障后期可明显影响视功能。     

One hundred consecutive pars plana vitrectomies using the vitrophage.

One hundred consecutive eyes underwent vitrectomy with the disposable vitrophage via a pars plana approach. Eyes were divided into two main categories based on opacity location-in the anterior or posterior segment. Patients with posterior segment opacities had diabetic retinopathy, nondiabetic vitreous hemorrhages, retinal detachments associated with vitreous hemorrhage, bands, or membranes, and intraocular foreign bodies or silicone oil. Patients with anterior segment opacities were treated for pupillary membranes resulting from surgical trauma or perforating injuries, and for complications following cataract extraction, such as capsule breakage and vitreous loss. Postoperatively, visual acuity improved in 68% of eyes with posterior segment opacities and in 85% of eyes with anterior segment opacities. Overall, visual acuity was 20/300 or better in 45% of eyes. There were only two intraoperative retinal tears and one postoperative rhegmatogenous retinal detachment.     

视网膜电图对玻璃体出血机化和玻璃体手术的意义

报告118例(133眼)由各种疾病引起的玻璃体出血机化患者的视网膜电图(ERG)检查结果,其中31例作了玻璃体手术,结果表明,ERG检查对玻璃体出血机化的患者,能客观地反映其网膜功能,并对玻璃体手术的预后有指导作用。术前ERG检查,a、b波下降越严重,视功能损害显著,术后视力的预后越差,同时证实,玻璃体机化膜是影响a、b波波幅和时间的一个因素。     

Retinal dysfunction in cancer-associated retinopathy is improved by Ca(2+) antagonist administration and dark adaptation

PURPOSE: It was recently found that recoverin acts as an autoantigen recognized by sera of patients with cancer-associated retinopathy (CAR), and that CAR-like retinal dysfunction is produced by intravitreous administration of anti-recoverin antibody in Lewis rat eyes. To examine the pathologic molecular mechanism of CAR, and to elucidate an effective therapy for CAR, the function and morphology of CAR were compared with those of phototoxic retinal damage, another form of photoreceptor dysfunction, and the effect of nilvadipine, a Ca(2+) antagonist, on the retinal degenerations was studied, using these models. METHODS: Under different illumination conditions and/or medication with nilvadipine, the functional and morphologic properties of the retinas were evaluated after intravitreous injection of anti-recoverin antibody into Lewis rat eyes (six rats, 12 eyes in each experimental condition), using electroretinogram (ERG), rhodopsin phosphorylation, and light microscopy. RESULTS: Anti-recoverin antibody administered into the vitreous of Lewis rat eyes induced a significant decrease and increase of ERG responses and rhodopsin phosphorylation levels, respectively, under cyclic or continuous light. Similar changes were observed in eyes of rats bred under continuous illumination that did not receive anti-recoverin antibodies. However, anti-recoverin antibody-induced retinal dysfunctions were not observed in rat eyes under dark conditions. Administration of nilvadipine, a Ca(2+) antagonist, to the anti-recoverin antibody-treated rats and rats with phototoxic retinal dysfunction caused significant improvement of the deterioration of ERG and normalization of rhodopsin phosphorylation. CONCLUSIONS: The present data indicate that anti-recoverin antibody-induced retinal dysfunction was functionally similar to phototoxic retinal dysfunction and was markedly suppressed under dark conditions or by systemic administration of a Ca(2+) antagonist.     

Retinal function after vitrectomy

PURPOSE: To study retinal function after vitrectomy. METHODS: Core vitrectomy was performed in 12 rabbits under standardized conditions using a vitreous cutting rate of either 600 or 1200 cuts/min. Full-field electroretinography (ERG) and multifocal electroretinography (mfERG) were performed pre- and postoperatively. Morphologic change was monitored by immunohistochemistry directed against glial fibrillary acidic protein (GFAP). RESULTS: Three days postoperatively, the b-wave amplitudes of all cone and rod responses of the ERG were significantly reduced in all vitrectomized eyes. At 28 days, the rod response was still reduced, but returned to normal by 58 days. No correlation was found between vitreous cutting speed and ERG findings. No reduction in the central cone function was detected in the mfERG. GFAP upregulation was found in the entire retina of vitrectomized eyes 3 days after surgery. GFAP expression was present after 28 and 58 days in eyes in which the vitreous cutting rate had been set to 600 cuts/min, but not in the 1200 cuts/min eyes. CONCLUSION: Pars plana vitrectomy transiently affects retinal function in rabbit eyes. Vitreous cutting speed is not related to the reduced function but appears inversely correlated to Müller cell activation, indicating that high-speed vitreous cutters are more lenient to the retina.     

玻璃体积血对兔眼视网膜影响的研究

目的　观察兔眼玻璃体积血后不同时间视网膜电图（electroretinogram，ERG）及超微结构的变化，为玻璃体积血治疗及预后评估提供实验依据。方法　新西兰大白兔32只，右眼均为实验眼，自体全血0.2 mL玻璃体内注射构建玻璃体积血模型，左眼为空白对照眼。随机分为4组，分别于造模后3 d、7 d、14 d及30 d选取一组常规检查后记录ERG的变化，随后处死动物立即摘取眼球制备标本观察超微结构。结果　实验性玻璃体积血3 d后常规ERG波形消失，造模后7 d逐渐出现。强闪光源刺激下，造模后3 d实验眼ERG的b波振幅与a波振幅与对照眼相比均明显降低（均为P＜0.01）。a波振幅在造模后30 d明显恢复，与对照眼无明显差异（P＞0.05），较造模后14 d差异有统计学意义（P＜0.05）；b波振幅在造模后7 d时开始回升，与对照眼无明显差异（P＞0.05），较造模后3 d差异有统计学意义（P＜0.05），造模后14 d及30 d接近正常。扫描电镜显示实验眼造模后3 d无玻璃体后脱离（posterior vitreous detachment，PVD）发生，造模后7 d部分性PVD占1/8，完全性PVD占1/8，造模后14 d部分性PVD占2/8，完全性PVD占5/8，造模后30 d部分性PVD占1/8，完全性PVD占7/8；对照眼各阶段未见PVD发生。结论　玻璃体积血后约1周可轻度可逆地影响视网膜功能并加速导致PVD形成，为实验及临床判断玻璃体积血后视网膜功能变化和临床玻璃体手术治疗的时间窗的选择提供了参考。     

Posterior vitreous detachment induced by nattokinase (subtilisin NAT): a novel enzyme for pharmacologic vitreolysis

PURPOSE: To investigate the effects of intravitreal injection of nattokinase (subtilisin NAT), a serine protease that is produced by Bacillus subtilis (natto), for induction of posterior vitreous detachment (PVD). METHODS: Different doses of nattokinase (1, 0.1, or 0.01 fibrin-degradation units [FU]) or physiologic saline as a control were injected into the vitreous cavity of rabbit eyes. Scanning electron microscopy was used to observe the retinal surfaces of four rabbit eyes per concentration. Histologic alterations were assessed by light microscopy, using four eyes from each group. Electroretinography (ERG) was performed to observe retinal function, ranging from 1 hour to 1 week after the nattokinase (1 or 0.1 FU) or saline solution administration, using four eyes from each group at each time point. Also, findings in all rabbits were monitored by slit lamp examination and by indirect ophthalmoscopy with a 20-D lens. RESULTS: Scanning electron microscopy showed smooth retinal surfaces, indicating the occurrence of PVD at 30 minutes after intervention in all the experimental eyes injected with 0.1 or 1.0 FU nattokinase, but none of the control eyes. Light microscopy and ERG analysis showed no critical change even after the use of 0.1 FU nattokinase, an amount sufficient to induce PVD. However, toxicity in the forms of preretinal hemorrhage and ERG changes was noted with the higher dose (1 FU) of nattokinase. CONCLUSIONS: The results suggested that nattokinase is a useful enzyme for pharmacologic vitreolysis because of its efficacy in inducing PVD.     

Vitreoretinal alterations following laser in situ keratomileusis: clinical and experimental studies

BACKGROUND: The presence of vitreoretinal changes following laser in situ keratomileusis in myopia is evaluated. METHODS: Clinically, 50 patients (100 eyes) with marked anisometropic myopia, 50 low-myopic eyes (<4.00 D) and 50 high-myopic eyes (>7.00 D) were prospectively evaluated pre- and postoperatively for the presence of newly recognized entoptic phenomena (vitreous floaters, light flashes, or both), and for vitreoretinal changes using indirect depressed fundus examination, a +90 D preset lens, Goldman three-mirror contact lens, and kinetic ultrasound (KU) before and after bilateral LASIK. Patients with previous partial or total posterior vitreous cortex detachment (PVD) were excluded. Experimentally, groups of adult pigs underwent KU, retinal fluorescein angiography (FA), and electroretinography (ERG) before and after applying the microkeratome suction ring for 30 s. RESULTS: Clinically, 8% (4 eyes) had positive perception of postoperative vitreous floaters in the low myopia group, and 32% (16 eyes) in the high myopia group. Postoperative light flashes were noted only in the high myopia group, in 12% of cases. Partial or total posterior vitreous cortex detachment was detected by biomicroscopy in 2% (1 eye) of the low and in 10% (5 eyes) of the high myopia group and by KU in 4% (2 eyes) of the low and in 24% (12 eyes) of the high myopia group. Experimentally, 2 pig eyes out of 12 developed partial PVD by KU, immediately after microkeratome suction ring application. All pig eyes showed significantly diminished ERG amplitudes during and immediately after suction ring application. No FA changes or delays in retinal circulation time were noted during or immediately after removal of the suction ring. CONCLUSIONS: Vitreoretinal alterations after LASIK were demonstrated clinically mainly by KU in high myopes. Experimentally, PVD were also demonstrated. Diminished ERG recordings with normal retinal circulation following suction ring application may suggest some transient choroidal circulation abnormalities.     

Endothelin-1-mediated retinal artery vasospasm and the rabbit electroretinogram.

Electroretinogram (ERG) changes invariably accompany the selective interruption of the retinal circulation that occurs in human central retinal artery occlusion. Since arteriolar ligation or ocular hypertension in the rabbit eye is occasionally used to model human central retinal artery occlusion, we conducted the present study to determine whether selective interruption of the retinal circulation of the rabbit eye alters retinal function as measured by the ERG. The vasoconstrictor, endothelin-1, was injected into the vitreous of rabbits' eyes to induce complete vasospasm and selective interruption of the retinal circulation. This procedure was compared to vascular ligation of the ophthalmic and ciliary arteries in which both the retinal and choroidal circulations were interrupted. A total of 8 rabbits was studied. Circulation was monitored angiographically in half of the eyes, and retinal function was monitored by the ERG in the remaining eyes. Endothelin-1 obliterated retinal arteriolar blood flow without affecting choroidal blood flow for at least 1 hr. Although ERG a-wave amplitude showed a small decline over 2 hr, b-wave and oscillatory potential amplitudes (measures of inner retinal function) showed no loss over this period. In contrast, ligation of the ophthalmic and ciliary arteries produced complete obliteration of both retinal arteriolar and choroidal blood flow and complete loss of the ERG after 2 min. Endothelin-1 induces acute, selective interruption of retinal arteriolar blood flow which has no significant physiologic effect on inner retinal function of the rabbit as monitored by the ERG. The avascular rabbit retina appears to be a poor choice for modeling human retinal artery occlusion.     

Preclinical investigation of fluorometholone acetate as a potential new adjuvant during vitreous surgery.

OBJECTIVE: To examine the effects of intravitreal fluorometholone acetate (FMT) on the morphology and function of the retina and to investigate its possible use for vitreous surgery. METHODS: Brown Norway rat eyes (n = 6, 12 groups) were injected with 0.05 ml of SF6 gas for vitrectomization. Four weeks later, FMT solution was injected into the vitreous cavity/subretinal space of the vitrectomized eyes at doses of 10, 20, and 40 mg/ml (0.05 ml/eye, n = 12 for each group). The retinal function was evaluated by electroretinography (ERG) at 4 and 8 weeks after FMT injection. Retinal toxicity was also assessed histologically by a light microscopy. Sham-operated eyes (0.05 ml of irrigating solution, n = 12) were used as control animals. FMT-assisted pars plana vitrectomy with internal limiting membrane (ILM) peeling was performed in primate eyes (n = 2). Retinal toxicity was assessed by ophthalmoscope, fluorescein angiography and electron microscopy three months after the vitreous surgery. RESULTS: There was no remarkable reduction in any ERG waves at either time interval at 4 and 8 weeks after the intravitreal/subretinal injection of FMT. No obvious histological change was observed in any of the rat eyes either. Using ophthalmoscope, fluorescein angiography and electron microscopy, the appearance of the primate retinas remained to be in a non-pathological condition. CONCLUSION: FMT appears to be a potentially useful tool in assisting vitreous surgery including safe ILM peeling.     

视网膜电图对视网膜血管阻塞的功能评估

目的：用视网膜电图评估视网膜血管阻塞的功能改变。方法：３０例视网膜中央静脉阻塞,１５例视网膜分支静脉阻塞,７例视网膜中央动脉阻塞和６例视网膜分支动脉阻塞按照ＩＳＣＥＶ的ＥＲＧ标准进行全视野网膜电图的检测。用Ｉ１蓝光、Ｉ１６红光和Ｉ１６白光估计暗视ＥＲＧ,用Ｉ１６红光和Ｉ８白光估计明视ＥＲＧ。记录ａ波和ｂ波的振幅和潜伏期及震荡电位。结果：视网膜血管阻塞的震荡电位异常率最高,其次为ｂ波;ＥＲＧ的异常率     

Q-Switched neodymium: YAG laser surgery of the vitreous

Fifty-nine eyes underwent vitreous surgery (vitreolysis) with the Q-switched Nd:YAG laser. This was used to cut vitreoretinal bands and membranes in 16 eyes and to clear persistent vitreous opacities in 25 eyes. The use of appropriate specialized contact lenses and modification of the standard slit-lamp delivery system were essential for vitreous YAG laser surgery. Successful results occurred in eyes where the target tissues were located at distances greater than 2 mm from the crystalline lens and the retina. Vision was improved in 18 eyes, unchanged in 40 eyes, and worse in 1. Complications included focal opacities of the crystalline lens in 5 eyes, retinal holes with detachment in 1 eye, and minor retinal hemorrhages in 4. Methods of preventing complications are discussed.Presented at the 1984 meeting of the Club Jules Gonin in Lausanne, Switzerland     

A new method for oxygen supply to acute ischemic retina

This paper introduces a new method for supplying oxygen directly to ischemic inner retina, using an oxygen source in the vitreous. Acute retinal vascular occlusion was created in cat eyes by direct pressure on the optic disk and its margins with a glass probe. The satisfactory occlusion of the retinal vessels was documented by direct observation, and functionally by recording the ERG. The vascular occlusion caused a large decrease in the size of the ERG b wave, with no change in the a wave amplitude. The oxygen source was a catheter made of strands of an oxygen-permeable membrane which was inserted into the vitreal cavity. After successful vascular occlusion was documented, 100% gaseous oxygen was perfused through the catheter while recording the ERG. In response to the perfused oxygen the b wave partially recovered. Ventilating the animal with 100% oxygen when the retinal vessels were occluded also caused recovery of the b wave amplitude. Termination of the vitreal oxygen source caused a decrease in b wave amplitude to the level previously observed after the occlusion of the retinal vessels. When the retinal circulation was restored by removal of the glass probe the b wave recovered. The results show that it is possible to supply adequate oxygen to the inner retina via the vitreous to replace the oxygen normally supplied by the retinal circulation. Modification of this method may be useful for the treatment of recent and incomplete retinal vascular occlusion.     

Vitreous opacities and outcome of vitreous surgery in patients with familial amyloidotic polyneuropathy

PURPOSE: To report the prevalence of vitreous opacities and the outcome of vitreous surgery in patients with familial amyloidotic polyneuropathy (FAP). DESIGN: Observational case series. METHODS: In 37 patients with FAP and the ATTR Val30 Met mutation, vitreous opacities were present in 14 eyes of 9 patients and vitrectomy combined with phacoemulsification and intraocular lens implantation was performed in five eyes of three patients. In six patients with the ATTR Tyr114Cys mutation, vitreous opacities were present in both eyes of all six patients and vitrectomy combined with phacoemulsification and intraocular lens implantation was performed in nine eyes of six patients. The mean follow-up period after vitreous surgery was 20.9 +/- 16.8 months (range, 3 to 52 months). RESULTS: The prevalence of vitreous opacities is much higher in patients with ATTR Tyr114Cys (100%) than in those with ATTR Val30 Met (24%). The mean age at the onset of vitreous opacities was significantly lower in the patients with ATTR Tyr114Cys (37.0 +/- 5.3 years) than in the nine patients with ATTR Val30 Met (52.8 +/- 9.1 years; P <.005). Visual acuity improved in all 14 eyes after vitreous surgery; however, final visual acuity decreased in one eye owing to the occurrence of a central retinal vein occlusion. Vitreous opacities mildly increased in two eyes. CONCLUSIONS: Our data suggest that the ATTR Val30 Met and ATTR Tyr114Cys mutations induce different clinical features of vitreous opacities. Vitreous surgery combined with phacoemulsification and implantation of an intraocular lens is a safe and useful treatment. Careful long-term follow-up should be performed.