大鼠后囊膜混浊模型的建立

目的建立一种新的、具有实用价值的大鼠后囊膜混浊(posterior capsule opacification,PCO)动物模型。方法12只SD(Sprague Dawley)大鼠随机分为4组,每组3只,每只大鼠双眼施行晶状体囊外摘除术(extracapsular lens extrac-tion,ECLE);在手术后即刻、第1天、第7天、第14天摘除眼球,进行组织病理学观察,研究残留晶状体上皮细胞(lensep-ithelial cells,LECs)增殖、移行和后囊膜的动态变化;应用方差分析比较LECs增殖数量。结果所有大鼠均成功施行ECLE手术。手术后即刻可见前囊膜下及赤道部有单层的LECs排列;术后第1天赤道部形成由2～3层细胞组成的细胞团块,LECs沿着囊膜向后囊迁移;术后第7天囊袋赤道部及后囊膜下形成多层细胞结构,赤道部晶状体纤维样物质增加,部分后囊膜出现明显皱褶;术后第14天囊袋赤道部及后囊膜下LECs形成团块,赤道部形成晶状体纤维样结构,赤道部Soemmering环形成。随时间推移,单位面积LECs数量明显增加(P<0.05)。结论大鼠ECLE手术后可成功建立后囊膜混浊模型。     

Use of a polylysine-saporin conjugate to prevent posterior capsule opacification.

PURPOSE: To determine the feasibility of applying a polylysine-saporin (PLS) conjugate to the lens capsule at surgery to prevent lens epithelial cell (LEC) proliferation and posterior capsule opacification (PCO). SETTING: Department of Research & Development, Bausch & Lomb Surgical, and Department of Ophthalmology, Saint Louis University, St. Louis, Missouri, USA. METHODS: Fluorescein-labeled polylysine was applied to the lens capsule of rabbits after phacoemulsification and analyzed histologically to determine the extent of binding to the lens capsule and surrounding tissues. The cytotoxin saporin was conjugated to polylysine using bifunctional cross-linkers. This PLS conjugate was applied to LECs in culture and to the lens capsules of rabbits. These eyes were monitored for PCO. RESULTS: Polylysine primarily bound to the lens capsule membranes, with little or no binding to surrounding tissues. When PLS was added to LECs in culture, it was internalized and destroyed the cells. Of 9 rabbit eyes treated with PLS during surgery, 1 remained free of PCO for the life of the animal (40 weeks), while 6 showed a delay of cortical regrowth approximately 2 to 3 times that of control eyes. CONCLUSIONS: Polylysine bound selectively to the lens capsule membrane. The PLS conjugation resulted in a toxic agent that targeted the lens capsule and destroyed proliferating LECs. The application of a PLS conjugate during surgery may prevent PCO.     

清除LECs对高度近视合并白内障患者囊袋稳定性的影响

目的:探讨清除晶状体上皮细胞(LECs)对高度近视合并白内障患者囊袋稳定性的影响。方法:回顾性分析2018-03/2019-04河北省眼科医院白内障科收治的合并高度近视的白内障患者98例120眼,根据术中是否进行囊膜LECs清除分为两组,A组患者50例60眼术中对前后囊膜进行抛光,B组患者48例60眼术中未对囊膜抛光。术后使用眼前节OCT检测两组患者有效人工晶状体位置(ELP)变化量、人工晶状体(IOL)偏心量、前囊口缩小程度,应用裂隙灯观察PCO发生情况及程度。结果:两组患者术后1d,3mo ELP变化量(0.16±0.06mm vs0.55±0.07mm)、前囊口收缩变化量(0.18±0.16mm vs0.92±0.13mm)及术后3mo IOL偏心量(0.02±0.005mm vs0.69±0.23mm)均有差异(P<0.05)。术后3mo,A组患者PCOⅠ级4眼,Ⅱ级2眼,Ⅲ级1眼;B组患者PCOⅠ级16眼,Ⅱ级8眼,Ⅲ级4眼,Ⅳ级3眼,两组患者发生PCO程度差异明显(Z=-4.765,P<0.01)。结论:囊膜LECs清除可减少前囊膜收缩程度,降低ELP改变量,增强囊袋-IOL复合体的稳定性,对减少术后PCO起得了良好的作用。     

去整合素kistrin对兔眼晶状体后囊Ⅳ型胶原表达的影响

背景 白内障囊外摘出术后残留的晶状体上皮细胞(LECs)增生是后囊膜胶原产生进而形成后发性白内障的生物学基础,去整合素可与细胞外基质(ECM)竞争结合整合素分子,理论上可以防治后发性白内障的形成,但其具体的作用机制有待进一步研究. 目的 研究去整合素kistrin对兔眼晶状体后囊Ⅳ型胶原表达的影响.方法24只新西兰大白兔按照随机数字表法分为kistrin注射组及生理盐水对照组,每组12只.两组兔均行右眼透明晶状体囊外摘出术,建立兔晶状体后囊膜混浊(PCO)模型,术毕kistrin注射组囊袋内注入80 mg/L kistrin 0.2 ml,生理盐水对照组注入等量生理盐水.术后1、3、5、7、14 d,在裂隙灯下观察实验动物晶状体PCO情况,并按照Odrich法进行分级.术后14d及3个月分别处死两组兔各6只,取出晶状体进行常规石蜡切片,行苏木精-伊红染色,光学显微镜下观察晶状体病理改变;行Masson染色观察晶状体囊袋内胶原纤维增生情况,免疫组织化学法检测兔晶状体后囊Ⅳ型胶原的表达. 结果 术后14 d,生理盐水对照组与kistrin注射组各级PCO的眼数差异无统计学意义(P=0.093),术后1、2、3个月,生理盐水对照组形成2～3级PCO的眼数明显多于kistrin注射组,差异均有统计学意义(P=0.041、0.014、0.022).晶状体组织学检查表明,术后14 d生理盐水对照组LECs层数明显多于kistrin注射组,瞳孔区后囊膜可见单层细胞黏附,kistrin注射组后囊则保持光滑,术后3个月可见生理盐水对照组晶状体后囊的LECs转化为纤维细胞,kistrin注射组较少见.Masson染色显示术后3个月生理盐水对照组晶状体前囊膜撕囊口处与后囊膜之间胶原纤维的蓝绿色染色明显多于kistrin注射组.免疫组织化学染色表明,术后14 d及30 d,生理盐水对照组晶状体后囊膜Ⅳ型胶原的灰度值均明显低于kistrin注射组,差异均有统计学意义(P=0.000、0.001). 结论 去整合素kistrin能够抑制兔眼晶状体囊外摘出术术后晶状体后囊LECs和Ⅳ型胶原增生.     

大鼠后发性白内障发生过程中晶状体纤维分化的初步研究

目的在组织学和mRNA水平上初步了解大鼠后发性白内障模型形成过程中晶状体纤维的分化。方法对48只SD大鼠行晶状体囊外摘除术,在术后即刻、1d、3d、1周、2周、1个月、2个月、3个月行裂隙灯显微镜观察和HE染色;取不同时间点后发性白内障组织,采用半定量逆转录聚合酶链反应法（RT-PCR）检测晶状体蛋白基因-αA、αB、βB1、βB2、βA2、γD的表达水平。结果所有大鼠术后均发生晶状体后囊膜混浊（PCO）。术后即刻,晶状体前囊膜下残留晶状体上皮细胞（LEC）;术后1d,LEC已增殖迁移至晶状体后囊膜中央区;术后3d,晶状体后囊膜中央轻度混浊、皱缩,晶状体囊袋内布满增生的LEC,周边部发生晶状体纤维分化。术后7d,后囊膜中央混浊继续加重,呈放射状皱褶,周边形成Seommering环。术后14d,瞳孔区囊膜组织纤维机化,Seommering环更为明显;术后1个月。新生晶状体纤维填满晶状体囊袋,形成类似正常晶状体的赤道部。术后2、3个月,晶状体纤维继续增生,体积接近正常晶状体。半定量RT-PCR显示术后αA、αB、βB1、βB2、βA2、γD mRNA的表达逐渐增加。结论SD大鼠行晶状体囊外摘除术后短期内即会发生明显的后发性白内障,并表达α、β和γ晶状体蛋白。该动物模型可用于后发性白内障的发病机制和晶状体再生的应用基础研究。     

Capsular bag opacification after experimental implantation of a new accommodating intraocular lens in rabbit eyes

PURPOSE: To evaluate the development of capsular bag opacification in rabbit eyes after implantation of an intraocular lens (IOL) designed to minimize contact between the anterior capsule and the IOL and ensure expansion of the capsular bag. SETTING: David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Ten New Zealand white rabbits had a study IOL (new accommodating silicone IOL [Synchrony, Visiogen, Inc.]) implanted in 1 eye and a control IOL (1-piece plate silicone IOL with large fixation holes) implanted in the other eye. Intraocular lens position, anterior capsule opacification (ACO), and posterior capsule opacification (PCO) were qualitatively assessed using slitlamp retroillumination photographs of the dilated eyes. Anterior capsule opacification and PCO were graded on a 0 to 4 scale after the eyes were enucleated (Miyake-Apple posterior and anterior views after excision of the cornea and iris). The eyes were also evaluated histopathologically. RESULTS: The rate of ACO and PCO was significantly higher in the control group. Fibrosis and ACO were almost absent in the study group; the control group exhibited extensive capsulorhexis contraction, including capsulorhexis occlusion. Postoperative IOL dislocation into the anterior chamber and pupillary block syndrome were observed in some eyes in the study group. CONCLUSIONS: The special design features associated with the study IOL appeared to help prevent PCO. Complications in the study group were probably caused by the increased posterior vitreous pressure in rabbit eyes compared to human eyes and the relatively large size of the study IOL relative to the anterior segment of rabbit eyes.     

BALB/c小鼠后发性白内障动物模型的建立和观察

目的建立BALB／c小鼠后发性白内障（posterior capsule opacification，PCO）动物模型并检测Sox1／2胚胎晶状体发育调控基因在PCO中的表达。方法腹腔麻醉联合表面麻醉下对30只BALB／c小鼠行右眼晶状体囊外摘出术，分别于术后即刻、3d、1周、2周和1个月对术眼进行裂隙灯显微镜及组织病理学检查，观察PCO形成的时间、部位、发展过程及组织形态学改变；采用逆转录聚合酶链反应（RT-PCR）方法检测Sox1／2胚胎晶状体发育调控基因在术后不同时间点PCO中的表达。结果裂隙灯显微镜观察：后囊膜皱褶、混浊由周边部向中央区发展伴Elschnig小体和晶状体纤维生成，其程度随时间推移日渐加重；再生晶状体形态和大小与正常晶状体相似但透明度明显下降。组织病理学检查：手术后即刻，赤道部和前囊膜下可见单层晶状体上皮细胞（lens elial cell，LEC），后囊膜表面无LEc及晶状体皮质残留；术后3d，赤道部LEC增生并迁移至后囊膜。囊袋周边部LEC开始早期纤维分化，但核仍靠近后囊膜表面；术后1周，赤道部LEC继续分化，细胞伸长呈带状伴核远离后囊膜表面；术后2周，周边部晶状体纤维细胞持续增多，形成与正常晶状体赤道部形态类似的弓形带；术后1个月。新生晶状体纤维几乎填充整个残余囊袋，排列欠规则，细胞核罕见。RT-PcR检测：术后3d、1周、2周及1个月的PC0组织中可检测到Sox1／2条带；术后即刻囊袋组织中无Sox1／2表达。结论BALB／c小鼠可成功建立PCO动物模型并检测到Sox1／2胚胎晶状体发育调控基因的表达，为在分子生物学水平上进一步探索PCO的发病机制提供了有利条件，具有重要的应用价值。【眼科新进展2007；27（2）：91-95]     

无防腐剂的1%利多卡因对兔晶状体上皮细胞影响的组织病理学研究

目的探讨无防腐剂的1％利多卡因对兔晶状体上皮细胞（LECs）的影响,为寻求白内障术中清除上皮,预防囊膜混浊的有效药物提供实验依据。方法采集29只兔（58只眼）晶状体前囊膜及赤道部囊膜标本,分为3组,对照组囊膜不加药物处理、BSS组囊膜用BSS浸泡1min、利多卡因组囊膜用利多卡因浸泡1min,后行锥虫蓝-茜素红染色,显微镜照相,观察LECs活性同时对死亡细胞进行计数;并通过HE染色及透射电镜观察兔LECs的组织病理学改变。锥虫蓝．茜素红染色及死亡细胞计数15只兔（30只眼）：其中对照组5只兔（10只眼）,BSS组5只兔（10只眼）,利多卡因组5只兔（10只眼）;HE染色9只兔（18只眼）：其中对照组1只兔（2只眼）,BSS组4只兔（8只眼）,利多卡因组4只兔（8只眼）;透射电镜5只兔（10只眼）：其中对照组1只兔（2只眼）,BSS组2只兔（4只眼）,利多卡因组2只兔（4只眼）。结果对照组兔晶状体前囊膜上皮细胞死亡率（1．51±0．39）％,赤道部囊膜上皮细胞死亡率（1．52±0．32）％;BSS组兔晶状体前囊膜上皮细胞死亡率（1．78±0．50）％,赤道部囊膜上皮细胞死亡率（1．77±0．47）％;利多卡因组兔晶状体前囊膜上皮细胞死亡率（13．01±4．67）％,赤道部囊膜上皮细胞死亡率（9．59±3．35）％。经嵌套试验的方差分析,利多卡因组细胞死亡率明显高于对照组与BSS组（P〈0．05）。HE染色显示对照组与BSS组兔LECs仍贴附于囊膜上,未见明显病理改变。利多卡因组部分细胞与囊膜间产生空隙,并从囊膜上脱落,细胞空泡变性。透射电镜观察下对照组与BSS组细胞间及细胞与囊膜间连接完整。利多卡因组部分细胞间及细胞与囊膜间的连接被破坏,细胞脱落较多,排列松散。细胞膜塌陷,胞质内有大量的空泡形成,细胞结构被破坏。结论无防腐剂的1％利多卡因能松解兔LECs间及细胞与晶状体囊膜间的连接,并可导致LECs变性、死亡。     

超声乳化术中前囊膜抛光预防后囊膜混浊的临床研究

目的探讨在白内障超声乳化术中行前囊膜抛光处理减少后发障发生的有效性和安全性.方法178例(235只眼)白内障患者在施行白内障超声乳化吸除及人工晶状体植入术中进行前囊膜抛光,术后对其视力、眼前节反应及后囊膜情况进行临床观察,随访1个月～1年,选择同期未行前囊膜抛光者220例(230只眼),作为对照组进行比较.结果(1)术中无并发症发生;(2)术后视力恢复快而良好;(3)术后后囊膜混浊发生8只眼(3.5%),均为轻度纤维型混浊,对视力无显著影响,而对照组术后后囊膜混浊发生23只眼(10.2%).对照组显著高于抛光组(P＜0.05).结论白内障超声乳化术中行前囊膜抛光处理可以减少术后后囊膜混浊的发生.作用机制可能是前囊膜抛光可大幅度地减少残留于前囊下的晶状体上皮细胞数量,阻止了上皮细胞的增殖及化生的来源,从而起到防止后囊膜混浊发生的作用.     

直角边缘囊袋张力环预防兔后囊膜混浊的实验研究

目的:探讨直角边缘囊袋张力环(capsule tension ring,CTR)预防兔后囊膜混浊(posterior capsule opacification,PCO)的作用。方法:新西兰兔20只随机分为两组,进行超声乳化晶状体摘除术后,实验组植入CTR和CraneOV-55C人工晶状体(intraocular lens,IOL),对照组只植入CraneOV-55CIOL。观察术后并发症和PCO情况。术后3mo行光镜和透射电镜检查,观察晶状体后囊膜的形态学变化。结果:术后3mo实验组和对照组都发生了明显的PCO(P>0.05),各组Soemmering环形成程度无统计学差异(P>0.05)。病理学检查发现,两组兔赤道部晶状体上皮细胞增生形成了巨大的Soemmering环,大量晶状体上皮细胞移行至后囊膜。结论:直角边缘CTR未能预防兔PCO的发生,有必要对其进一步改进。     

改良大鼠后囊膜混浊模型的建立及晶状体上皮细胞的变化

目的:改良法建立大鼠后发性白内障动物模型并观察LEC在PCO过程中的动态变化。方法:SD大鼠50只在连续环形撕囊、水分离后行晶状体囊外摘除术(ECLE),娩核后使用无菌空气恢复前房。分别于术后0,3,7,14及28d对术眼进行裂隙灯检查并处死动物,摘除眼球行光镜观察,免疫组化检测LEC的α-SMA表达。结果:100%术眼后囊膜存在,84%的鼠眼可用于检测。术后0h于前囊下和赤道部的内表面观察到LEC。PCO在术后3d出现,出现囊膜皱缩,整个晶体囊膜出现纺锤形细胞。术后7d时后囊膜明显混浊,见较多纺锤形细胞分布。所有动物于术后14d出现明显后囊膜皱缩,可见新生晶体纤维。术后28d见明显后囊膜增厚,新生晶体纤维填充囊袋,后囊膜未见细胞。LEC形态及分布恢复到术后0h状态。免疫组化检测见术后3d时α-SMA阳性表达。结论:改良法成功建立大鼠PCO模型,LEC在PCO形成中出现形态和分布上的动态变化。其将为在分子水平上探索PCO的发病机制及防治方法提供合适研究载体。     

直角边缘人工晶状体预防兔后囊膜混浊的实验研究

目的探讨直角边缘人工晶状体（intraocular lens，IOL）预防后囊膜混浊（posterior capsule opacification，PCO）的作用。方法30只新西兰兔进行超声乳化晶状体摘出联合囊袋内IOL植入术后，随机植入Crane OV-55CP、Crane OV-55C、Alcon TYPE 5C 3种IOL之一。观察术后并发症和PCO情况。术后3月行光镜和透射电镜检查，观察晶状体后囊膜的形态学变化。结果术后3月Crane OV-55CP组的PCO程度比Crane OV-55C和Alcon TYPE 5C组轻（P〈0．05），各组Soemmefing环形成程度无差异（P〉0．05）。病理学检查发现Crane OV-55CP组兔赤道部增生的晶状体上皮细胞在人工晶状体的直角边缘处受到了阻挡。Crane OV-55C和Alcon TYPE 5C组大量晶状体上皮细胞迁移至后囊膜。结论直角边缘IOL延缓了兔PCO的发生、发展，是预防PCO简便安全有效的方法。     

A new model of posterior capsule opacification in rodents

PURPOSE: To describe a new model of posterior capsule opacification (PCO) in rodents METHODS: An extracapsular lens extraction (ECLE), by continuous curvilinear capsulorrhexis and hydrodissection, was performed in 42 consecutive Brown Norway rats. Animals were killed at 0, 6, and 24 hours and 3, 7, and 14 days after surgery. Eyes were enucleated and processed for light microscopy and immunohistochemistry. RESULTS: In 34 (81%) of the animals the operated eye appeared well healed before death, with a clear cornea and a well-formed anterior chamber. In eight (19%) there was no view of anterior segment structures because of hyphema, fibrin, or corneal opacification. PCO was clinically evident 3 days after ECLE and was present in all animals at 2 weeks. Immediately after ECLE, lens epithelial cells (LECs) were present in the inner surface of the anterior capsule and lens bow. Twenty-four hours after surgery, LECs started to migrate toward the center of the posterior capsule. At 3 days, multilayered LECs, some spindle shaped, were present throughout the lens capsule. Capsular wrinkling was apparent. Lens fibers and Soemmering's ring were observed in all animals 14 days after surgery, indicating some degree of cellular differentiation. Activated macrophages were present in greater numbers at 3 and 14 days after surgery (P < 0.05), when proliferation and migration of LECs appeared to be greatest, and lens fiber differentiation was evident, respectively. CONCLUSIONS: In rodents PCO occurs after ECLE and is associated with low-grade inflammation, mostly of mononuclear macrophages. Although no intraocular lens implantation was performed, this model appears to be valuable for studying the sequence of events that leads to PCO after cataract surgery and the extracellular matrix cues that promote lens fiber differentiation.     

Comparison of posterior capsule opacification in rabbit eyes receiving different administrations of rapamycin

Background

Posterior capsule opacification (PCO) is a common complication after cataract surgery. The purpose of this study was to determine the effects of three administering ways of rapamycin (RAPA) on the formation of PCO in rabbit eyes for 12 weeks.

Methods

Eighty rabbits were divided into four groups, according to the different administrations of RAPA which they received. These were: (1) the control group, (2) the irrigation-treated group — 5 ng/ml intraoperative RAPA irrigation solution, (3) the eye-drop-treated group — 2 mg/ml RAPA eye drops, and (4) the IOL-treated group — RAPA–poly(lactic-co-glycolic) acid (PLGA) loaded on the surface of intraocular lens (IOLs) (RAPA-PLGA-IOLs). All right eyes were treated with lens extraction plus IOL implantation, receiving relative administrations of RAPA. RAPA concentrations in the aqueous humour were determined by high performance of liquid chromatography (HPLC). The anterior chamber (AC) response was observed through slit-lamp biomicroscopy. After 12 weeks, the degree of PCO was determined by clinical evaluation. The histological sections, immunohistochemistry expression of proliferating cell nuclear antigen (PCNA) in the lens capsule were conducted.

Results

In the early period, AC response for both experimental and control eyes were similar. In the IOL-treated group, RAPA reached its peak at 25.68?±?0.74 μg/ml on the 4th day, and it was detectable until 8 weeks afterwards. However, in the other groups, RAPA could not be detected all the time. Compared with other groups, in the IOL-treated group, PCO was greatly alleviated; only a few layers of the lens epithelial cells (LECs) and a little proliferative material around the posterior capsules, and a significantly weak expression of PCNA in the nuclei of LECs. By contrast, there was no significant statistical difference in eye-drop-treated or irrigation-treated eyes and control eyes respectively.

Conclusions

Intraocular RAPA-PLGA-IOL was a promising, effective, and safe administration to prevent PCO compared with other methods in the rabbit PCO model.     

Removal of lens epithelial cells and the effect on capsulorhexis size

PURPOSE: To assess the long-term effects of lens epithelial cell (LEC) removal on capsulorhexis opening size. SETTING: Dorset County Hospital, Dorchester, United Kingdom. METHODS: This prospective randomized control study included 39 eyes of 38 patients. Twenty eyes were selected randomly for removal of LECs from the anterior capsule as part of routine cataract operation comprising phacoemulsification with intraocular lens (IOL) implantation. The other 19 eyes were used as controls in which the LECs were not removed. All surgeries were performed by 1 surgeon (A.T.). All patients had silicone IOL (Allergan SI-40) implantation. The capsulorhexis opening size was determined immediately after surgery and 2 weeks and 6 months after surgery. Data on treatment outcome of the cataract surgery were analyzed statistically. RESULTS: Six months postoperatively, the size of the capsulorhexis had statistically significant increased in the study group that had LECs removed (mean increase 1.07 +/- 1.70 mm(2); paired Student t test P=.01), whereas the capsulorhexis size had statistically significant decreased in the control group (mean decrease -3.38 +/- 2.37 mm(2); paired Student t test, P<.0001). The difference in changes in the capsulorhexis areas between the 2 groups was also highly statistically significant (independent-sample Student t test, P<.0001). CONCLUSION: Removal of anterior subcapsular LECs by aspiration helped maintain the size of the capsulorhexis opening and thus can help prevent capsule contraction syndrome.     

When may the posterior capsule be preserved in pediatric intraocular lens surgery?

PURPOSE: To refine indications for primary posterior capsulotomy (PPC) in conjunction with posterior chamber intraocular lens (PCIOL) implantation for cataract in childhood. DESIGN: Noncomparative case series. PARTICIPANTS: Patients 1 to 13 years old who underwent cataract extraction with intent to preserve the posterior lens capsule and PCIOL implantation between January 1992 and December 1998 at a pediatric hospital. METHODS: Medical records were reviewed to determine the frequency and timing of posterior capsule opacification (PCO) after PCIOL surgery with preservation of an intact posterior capsule. Comparison of pseudophakic PCO rates for groups defined by age and several possible risk factors. Assessment of safety and efficacy for PPC with anterior vitrectomy performed through a limbal incision in cases where the posterior capsule could not be preserved. MAIN OUTCOME MEASURES: Need for neodymium:yttrium-aluminum-garnet laser capsulotomy or surgical membranectomy to treat PCO. RESULTS: PCO occurred in 40% of 30 eyes with intact posterior capsule. Mean follow-up duration was 22 months for eyes that had PCO develop and 24 months for those in which the posterior capsule remained clear. Laser capsulotomy was required for 64% of 14 eyes in the 1- to 6-year-old age range but for only 19% of 16 in the 6- to 13-year-old range (P < 0.05). Mean time from surgery to PCO was 7 months for the younger group and 13 months for the older group. A need for repeated capsulotomy (one eye) or membranectomy with anterior vitrectomy (two eyes) was found only in the younger age group. There was no association of PCO with trauma history, cataract type, residual lens cortex, IOL position, or postoperative fibrin clot. Final vision was possibly compromised as a result of PCO in one eye with amblyopia. None of 24 eyes in which PPC with anterior vitrectomy was performed out of intraoperative necessity before primary PCIOL implantation had secondary opacification develop. No reduction in postoperative vision was attributable to PPC. CONCLUSIONS: PPC seems to be advisable for children less than 6 years old when cataract extraction with PCIOL implantation is performed. Preservation of the posterior capsule remains appropriate for older children with pseudophakia.     

EDTA与多聚赖氨酸的铰链物抑制兔后发性白内障的实验研究

目的：探讨EDTA与多聚赖氨酸的铰链物对兔后发性白内障的防治作用。方法：将20只新西兰白兔40眼随机分为A,B,C,D共4组,4组均行透明晶状体囊外摘除术。A组为对照组,术中灌注液为BSS;B,C,D组为治疗组,术中灌注液分别为浓度为10mg/L的EDTA、多聚赖氨酸、EDTA与多聚赖氨酸的铰链物的BSS溶液。2mo后行晶状体后囊膜切片,HE染色统计晶状体上皮细胞（LECs）的密度;并行免疫组织化学染色,用医学图象分析系统检测PCNA表达平均光密度（灰度值OD）。结果：经HE染色,后囊膜LECs密度B和D组较A和C组少,且D组的LECs密度小于B组,均有显著性差异（P〈0.01）;A和C组的LECs密度相差不大,无统计学差异（P〉0.05）。免疫组织化学进行平均光密度测定,A和C组PCNA表达强阳性,B组呈部分阳性表达,D组阳性表达较B组更少。B和D组与A组、B组与D组均有显著性意义（P〈0.01）。A组和C组无显著差异性（P〉0.05）。结论：在活体兔眼中,EDTA、多聚赖氨酸与EDTA的铰链物均有抑制兔LECs增殖的作用,且EDTA与多聚赖氨酸的铰链物组对LECs的抑制作用优于EDTA组,多聚赖氨酸组对LECs的抑制作用不明显。     

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.     

Pharmacologic prevention of posterior capsule opacification: in vitro effects of preservative-free lidocaine 1% on lens epithelial cells

PURPOSE: To assess the in vitro effectiveness of preservative-free lidocaine 1% in removing lens epithelial cells (LECs) from the anterior capsule and to evaluate the effect of lidocaine on the LECs. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Eight rabbits (16 eyes) were used in the study. After the rabbits were killed, the eyes were enucleated and divided into 2 groups. In Group 1 (n = 8 eyes), LECs were exposed to preservative-free lidocaine 1% or balanced salt solution (BSS) for 1, 2, or 5 minutes. The anterior capsules were then stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken and analyzed for LEC damage. In Group 2 (n = 8 eyes), hydrodissection was performed with 1 of the agents, followed by phacoemulsification and cortical cleanup. The LEC attachment to the anterior capsule was evaluated by histopathology. RESULTS: Anterior capsule fragments irrigated with BSS showed no LEC nuclear staining; ie, no direct toxic effect. In those irrigated with preservative-free lidocaine 1%, the LECs showed mild toxicity; some cells showed blue nuclear staining. After hydrodissection with lidocaine, the capsules were almost free of LECs; after hydrodissection with BSS, the capsules showed a normal layer of LECs attached to the anterior capsule. CONCLUSIONS: Preservative-free lidocaine 1% may help diminish the amount of live LECs by facilitating cortical cleanup, by loosening the desmosomal area of cell-cell adhesion with decreased cellular adherence, or by a direct toxic effect. The use of this agent may help prevent posterior capsule opacification.     

Role of posterior capsulotomy with vitrectomy and intraocular lens design and material in reducing posterior capsule opacification after pediatric cataract surgery

PURPOSE: To study the effect of primary posterior capsulotomy with anterior vitrectomy (PPC + AV) and intraocular lens (IOL) design and material on the development of posterior capsule opacification (PCO) after pediatric cataract surgery. SETTING: Tertiary care institution in India. PATIENTS: Sixty-four eyes of 52 children ranging in age from 3 months to 12 years who had cataract extraction with IOL implantation were prospectively evaluated for a minimum postoperative period of 2 years. METHODS: Thirty-two eyes received a hydrophobic acrylic lens with a truncated, square edge and 32, a single-piece poly(methyl methacrylate) (PMMA) lens that was not heparin surface modified. Sixteen eyes in each IOL group had PPC + AV; in the remaining 16 eyes in each group, the posterior capsule was left intact. RESULTS: Postoperatively, 25 eyes in the intact capsule group and 5 in the PPC + AV group developed PCO; the difference between groups was significant (P<.05). Of eyes with an intact capsule, 12 with an acrylic IOL and 13 with a PMMA IOL developed PCO (P>.05). In the PPC + AV group, 2 eyes with an acrylic IOL and 3 with a PMMA IOL developed PCO (P>.05). Overall, 14 eyes with an acrylic lens and 16 eyes with a PMMA lens developed PCO (P>.05). After surgery, there was a significant short-term delay in the development of PCO in the acrylic group (14 eyes; mean 6.66 months +/- 1.57 [SD]) compared to the PMMA group (16 eyes; mean 3.16 +/- 0.83 months) (P<.05). CONCLUSIONS: It is the management of the posterior capsule rather than IOL design and material that influences the incidence of PCO after cataract surgery in children. Development of PCO in the postoperative period was delayed with a hydrophobic acrylic IOL with square edges compared with a PMMA lens without square edges.