兔眼脉络膜上腔多通道微电极阵列植入后视网膜电刺激阈值的研究

目的研究兔眼脉络膜上腔多通道微电极阵列芯片植入术后,电刺激视网膜诱发的中枢电诱发电位（EEP）的阈值。方法将多通道刺激电极（二氯代环二聚体为基底,铂电极）植入9只青紫蓝兔左眼后极部的脉络膜上腔,将铂丝制成的参比电极置于玻璃体腔,硬膜外放置记录电极。刺激电极采用双向刺激的方式发出电刺激,在中枢记录EEP。测量产生EEP的阈值,连续记录30次取其平均值。实验结束后处死动物取出眼球行组织学检查。应用检眼镜和OCT检查评价多通道微电极阵列芯片植入和清除后对兔眼组织的安全性。结果多通道微电极阵列芯片成功植入9只实验兔眼的脉络膜上腔。当脉络膜上腔刺激电极发出电刺激后,可以在硬脑膜外的记录电极处记录到EEP,阈值为（107．14±17．14）nC,（68．20±10．91）μC／cm。光学显微镜下显示视网膜结构完整,刺激电极附近无明显的组织结构的破坏。检眼镜及OCT检查显示相应的脉络膜组织与邻近组织间连接紧密。结论置于脉络膜上腔的电极发出的电刺激可以有效地诱发出EEP,且其阈值较低;脉络膜上腔是较理想的视网膜假体放置部位。     

脉络膜上腔给药治疗兔眼穿通伤

目的 比较脉络膜上腔给药与全身给药治疗眼穿通伤的疗效。方法 16只日本大耳白兔制成双眼穿通伤模型,分为 经脉络膜上腔给药与全身给药两组,经处理后行视网膜脱离及玻璃体浑浊评级、眼底造影及组织病理研究。结果 脉络膜上 腔给药组抑制炎症和增殖反应的效果优于全身给药组。结论 脉络膜上腔给药安全有效,可作为一种新的穿通伤治疗手段。     

兔眼脉络膜上腔出血模型建立及自然转归的研究

目的建立兔眼脉络膜上腔出血（SCH）模型,观察其自然转归。方法经隧道式巩膜全层切口注入兔眼脉络膜上腔自体抗凝血建立SCH模型,并行检眼镜、B型超声及组织病理学观察。结果术后实验组兔眼均出现了SCH。术后1h视网膜及脉络膜呈明显红色隆起,边界清楚,出血范围为8～10个视盘直径;术后1d出血范围扩大、隆起度降低,术后3d出血开始吸收,术后7d大部分吸收,术后14d基本吸收,术后21d完全吸收。术后1～3d脉络膜上腔炎性细胞浸润,术后7d脉络膜上腔血液部分溶血,术后14d完全溶血,光感受器层发生空泡变性,睫状体萎缩。结论经隧道式巩膜全层切口注入兔眼脉络膜上腔自体抗凝血建立SCH模型的方法简单实用、安全可靠、重复性较好,为视网膜受损及相关治疗提供依据。     

脉络膜新生血管伴自发性脉络膜上腔出血的临床分析

目的:描述脉络膜新生血管(choroidal neovascularization,CNV)伴自发性脉络膜上腔出血患者的临床特征,探讨其发生的高危因素以及玻璃体视网膜手术的疗效。方法:CNV伴自发性脉络膜上腔出血3例3眼,男性,年龄58~75(平均62岁)。玻璃体脉络膜积血病程6~12d(平均8±4.3d)。术前视力2眼手动,1眼无光感。眼压16~28mmHg(平均19±4.8mmHg)。2眼伴前房红褐色积血,3眼伴重度玻璃体混浊。FFA显示既往均有黄斑区CNV,其中1例健眼有玻璃膜疣。屈光力正常。眼轴22~24mm,双眼无显著性差异(P>0.05)。B超均显示玻璃体积血、出血性视网膜脱离并脉络膜脱离。所有患者均接受常规脉络膜上腔放血、巩膜外环扎、玻璃体切割、视网膜切开、血管膜和积血块清除、视网膜复位及眼内硅油充填术。追踪观察6~34mo。结果:所有患者均为一次手术即成功引流脉络膜上腔积血,术中发现脉络膜下液为黑红色血性积液,玻璃体积血呈灰黑色,术毕脉络膜和视网膜平复。术后2眼发生前部增殖性玻璃体视网膜病变(anterior proliferative vitreoreti-nopathy,aPVR),1眼再次手术。最终在取出硅油后,2眼(67%)视网膜获得解剖复位,术后视力0.05~0.1,1眼无光感。结论:CNV所致的自发性脉络膜上腔出血伴出血性视网膜脱离非常少见,这类患者眼部病变发展迅速,脉络膜上腔积血可渗透到前房,眼压正常或偏高。玻璃体视网膜手术可取得较好的效果。     

视网膜脱离术中限局性脉络膜上腔出血

1700例1720眼孔源性视网膜脱离经巩膜外冷冻、硅胶外加压或联合环扎术，7例术中发生限局性脉络膜上腔出血，其发生率为0．4％。就该并发症的病因学、临床表现、治疗及预后作简要讨论。     

壳聚糖药膜植入脉络膜上腔治疗兔眼细菌性眼内炎

目的比较玻璃体腔注射万古霉素联合脉络膜上腔植入载有曲安奈德(triamci-nolone,TA)的壳聚糖膜与其玻璃体腔注射TA对兔外源性金黄色葡萄球菌的治疗作用。方法30只健康青紫蓝兔均于右眼内注射ATCC25923标准金黄色葡萄菌0.1×109CFU.L-1混悬液0.1mL。建立眼内炎模型后24h,将实验动物随机分为3组,均对右眼进行干预,每组10眼,A组玻璃体腔注射万古霉素、B组玻璃体腔注射万古霉素 TA混悬剂、C组玻璃体腔注射万古霉素 脉络膜上腔植入壳聚糖缓释药膜(载TA)。干预后每日裂隙灯及间接眼底镜观察;注射细菌后24h及干预后14d行B超检查;干预5d行玻璃体腔细菌培养;干预后14d摘除所有术眼于光镜下观察组织病理学改变。结果C组较A、B组炎症明显减轻。不同时间3组进行临床炎症评分,C组各项评分明显低于其他2个对照组,治疗后不同时间A、B、C3组总的炎症评分有显著性差异均为P=0.000,组间对比C组与A、B2组均有显著性差异P=0.000,A、B2组间无显著性差异(P<0.05)。细菌学培养检出率无统计学意义P=0.830;B超显示A、B、C3组视网膜脱离发生率有显著性差异(P=0.015);光镜下见C组眼部各组织结构完整,角膜、前房、玻璃体、视网膜病理学评分A、B、C3组间有显著性差异(P均为0.000),组间比较除A、B2组间视网膜评分有显著性差异(P=0.011),其余各组间各项病理评分均无显著性差异。结论壳聚糖药膜植入脉络膜上腔安全有效,可以成为治疗细菌性眼内炎的一种新的治疗方法。     

脉络膜上腔不同给药途径治疗葡萄膜炎的实验研究

目的 比较脉络膜上腔给药与其他途径局部给药治疗葡萄膜炎的疗效。方法 36只青紫蓝兔先制作实验性葡萄膜炎模型，分别经脉络膜上腔给药、球内注射、筋膜下注射曲安奈德1mg后，定期测定房水蛋白量、细胞数并行炎症评分、眼底造影及组织病理研究。结果 3种给药途径疗效优劣依次为脉络膜上腔给药、玻璃体内给药、筋膜下给药。结论 脉络膜上腔给药安全有效，可作为一种新的葡萄膜炎治疗手段。     

Krupin眼阀门植入术后迟发性脉络膜上腔出血1例

患者,男,34岁左眼抗青光眼术后1年,眼红,胀痛伴同侧头痛6个月,于2000年7月25日入院.1年前,因左眼外伤后继发青光眼,在本院行左眼小梁切除联合白内障摘除术,术后眼压降至正常.     

Efficacy and reliability of long-term implantation of multi-channel microelectrode arrays in the optical nerve sheath of rabbit eyes

In addition to epiretinal and subretinal areas, the optic nerve (ON) is also a candidate location for implanting visual prosthesis to restore vision of patients with retinitis pigmentosa (RP). Since the ON receives all the signals from the retina, stimulating the ON may potentially evoke phosphenes over a wider range of visual field. In this study, we designed a 9-channel microelectrode array and implanted it between the dura mater and pia mater of rabbit ONs by lateral orbitotomy. We recorded the current thresholds and evaluated the efficacy of the array using electrically evoked potentials (EEPs). Spatial discrimination of approximately 20° was verified by EEP maps over visual cortex. A large area of the visual field (over 130° along horizontal meridian) could be activated by this microelectrode array. Visual evoked potentials (VEPs) and different pathological examinations were used to examine potential damage of ONs. One year post implantation, we did not notice significant damages to either the ONs or the microelectrode arrays. EEPs were successfully recorded up to 6 months post implantations. However, further studies are still needed to reduce fibrous encapsulation of the microelectrode array, which resulted in a gradual elevation of current thresholds to elicit EEPs.     

Intraocular lens implantation in phakic rabbit eyes

Three sizes (13.5 mm, 17.5 mm, and 18.5 mm) of open loop, one piece, poly(methyl methacrylate) anterior chamber intraocular lenses (IOLs) were implanted in 12 phakic rabbit eyes to evaluate the effect of the IOL on the crystalline lens and the anterior chamber. Six eyes were used as a control group. Minimum follow-up was four weeks. All the IOLs touched the crystalline lenses, and on the first postoperative day, round subcapsular lens opacities were found in all eyes in the area of IOL contact. The lens opacities became more dense with time. Only one eye in the control group showed a subcapsular opacity, which was linear rather than round. Anterior chamber inflammation was 1+ to 2+ in ten eyes (80%) in the IOL group during the first and second weeks, whereas minimal inflammatory changes occurred in the control group. These results suggest that with current IOL technology, IOL insertion in the phakic eye to correct refractive errors results in a high incidence of cataract if IOL-to-lens touch occurs.     

Autologous hair implantation for drainage in rabbit eyes

Autologous hair material was used as a wick for drainage from the anterior chamber into the subconjunctival space in 8 rabbits. Though pressure reduction and methylene blue leakage was evident in the operated eyes, the histological observations seemed rather discouraging.     

Autologous hair implantation for drainage in rabbit eyes

Autologous hair material was used as a wick for drainage from the anterior chamber into the subconjunctival space in 8 rabbits. Though pressure reduction and methylene blue leakage was evident in the operated eyes, the histological observations seemed rather discouraging.     

Effect of bag-in-the-lens implantation on posterior capsule opacification in human donor eyes and rabbit eyes

PURPOSE: To evaluate bag-in-the-lens implantation by studying the feasibility of implanting a new type of intraocular lens (IOL) and the occurrence of posterior capsule opacification (PCO) in human postmortem eyes and in eyes of living rabbits. SETTING: Department of Ophthalmology, University of Antwerp, Belgium, and Netherlands Research Institute of Amsterdam, Amsterdam, The Netherlands. METHODS: The IOL was implanted in 10 postmortem human donor eyes (in vitro study) and in 17 eyes of 10 rabbits (in vivo study). The postmortem capsular bags were cultured for 4 to 6 weeks, and the rabbits were killed 1 to 5 months after implantation. All capsular bags with the bag-in-the-lens were examined by light microscopy and scanning electron microscopy. RESULTS: The IOL design was highly effective in restricting lens epithelial cell (LEC) proliferation in the remaining lens bag in human donor eyes and in rabbit eyes. In eyes in which the capsules were not positioned well within the groove of the IOL, LEC proliferation and PCO occurred. CONCLUSION: Bag-in-the-lens implantation was highly effective in preventing PCO in vitro and in vivo provided the anterior and posterior capsules were secured properly in the peripheral groove of the IOL.     

Perfluorocarbon gases in the suprachoroidal space of rabbit eyes

Four perfluorocarbon gases were injected into the suprachoroidal space of rabbit eyes. Temporary, expanding choroidal detachments were observed in all cases. Depending on the amount of gas injected (0.1 or 0.2 cc, respectively), they lasted 1 or 2 days in the case of perfluoromethane, 4 or 5 days with perfluoroethane, 6 or 8 days with perfluoropropane, and 9 or 11 days with perfluoro-N-butane. Due to its longevity, perfluoro-N-butane appeared to be the most suitable gas for temporary buckling of the suprachoroidal space in rabbit eyes.     

Transretinal electrical stimulation by an intrascleral multichannel electrode array in rabbit eyes

Background A new method of stimulating the retina electrically, called suprachoroidal transretinal stimulation (STS), was shown to be effective in eliciting electrically evoked cortical potentials (EEPs) in Royal College of Surgeons (RCS) rats. Before extending this technique to patients, it is important to determine its safety and feasibility in eliciting EEPs from medium-size animal (rabbits). The purpose of this study was to determine the safety and efficacy of the surgical procedures used to implant an multichannel electrode array into a scleral pocket, and to determine whether the implanted electrodes can stimulate the retina effectively.Methods These acute experiments were conducted on six rabbits. An array of eight gold microelectrodes, embedded in polyimide, was implanted into a scleral pocket over the visual streak area. The size of the microarray was 2×4×0.180 mm. The reference electrode was implanted into the vitreous. The electrode array and reference electrodes were connected to a stimulator to deliver monophasic current pulses. Cortical responses were recorded with a stainless steel electrode implanted into each rabbits skull over the visual cortex. After the experiment, the eyes and electrodes were examined histologically.Results The surgical procedures for electrode implantation were accomplished without serious complications. EEPs were recorded after monophasic electrical pulse stimulation from each electrode. The mean threshold for EEPs was 55.0±10.0 A with a 0.5-ms duration inward current pulse. The charge delivered at threshold was about 27.5 nC, and the charge density was about 56.0 C/cm². Histopathological examination of the retinal tissue around the area of stimulation did not show damage at the light microscope level with the electrical parameters used.Conclusions Our technique for STS with an intrascleral microelectrode array is safe in rabbit eyes, and EEPs were elicited by current densities that did not induce tissue damage. These results suggest that STS via intrascleral multichannel electrodes is a feasible method for stimulating the retina.H.K., T.Y., and S.N. are employees of NIDEK Co.     

视网膜视细胞的成片移植

目的 探索用准分子激光切削技术制备视网膜单层细胞植片,经内入路视网膜下腔的单层视细胞成片移植。方法 用准分子激光对大鼠视网膜进行切削,制取单层视细胞植片,此后,按内入路手术方法进行了兔视网膜下腔的异种移植。结果 切削后所得视细胞植片由单层视细胞组成,结构完整,包括外丛状层、外核层和外节层;视细胞植片经明胶包埋后被准确植入宿主视网膜下腔中,移植术后第1,2天宿主观视网膜未能复位,呈脱离状态,移植物没能与视网膜色素上皮层相贴;移植后10天,宿主视网膜复位,视细胞移植片平铺于宿主视网膜下腔中,植片视细胞外节也宿主视网膜色素上皮层相贴;移植后10天,宿主视网膜复位,视细胞移植片平铺于宿主视网膜下腔中,植片视细胞外节与宿主视网膜色素上皮层相贴,未见明显免疫排异现象。结论 准分子激光制备单层视细胞植片方法简单、可行;初步观察到内入路单层视细胞成片移植后,视细胞植片能够在宿主视网膜下腔中以正常生理位置存活;视网膜下腔为理想的视网膜移植的受位。