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。     

疏水丙烯酸酯囊袋张力环的制作及其对晶状体上皮细胞生长和后囊膜混浊的抑制作用

目的研制以疏水丙烯酸为材料直角矩形设计的囊袋张力环(capsule tension ring,CTR),对其生物相容性进行鉴定,观察其在体外对人晶状体上皮细胞(human lens epithelial cells,HLEC)的生长抑制作用及在兔眼中抑制后囊膜混浊(posterior capsule opacification,PCO)的效果。方法将甲基丙烯酸苯乙酯和丙烯酸苯乙酯按一定比例聚合成疏水丙烯酸酯,进一步加工成直角矩形设计、闭合直径10.5mm、宽0.5mm、高0.2mm的开放式CTR,并对其进行细胞毒性试验、热原试验、眼刺激试验等生物相容性测试。取白内障术中前囊膜进行原代HLEC培养,将第2代细胞接种于CTR内进行细胞实验,观察其对细胞的移行作用。动物实验选用青紫兰兔,对照组4只仅接受白内障超声乳化吸出术;实验组4只接受白内障超声乳化同时植入CTR,观察术后炎症反应及前、后囊膜混浊情况。结果细胞毒性为1级,热原试验中试品个体升温均在0.6℃以下,且升温总值为0.1℃,眼刺激试验无异常,证明该材料有较好的生物相容性。体外细胞实验中,所有环均未见有细胞在环上生长或越过环向外生长。兔眼实验中,所有术眼术后均出现不同程度的前房渗出,1～2周基本吸收,术后1个月观察发现实验组兔眼的后囊膜均保持清晰,对照组兔眼的后囊膜出现不同程度的PCO。结论兔眼白内障术中植入疏水丙烯酸材料CTR可以降低PCO的发生。     

阿霉素药物缓释系统抑制人工晶状体植入术后后囊膜混浊的实验研究

目的 探讨阿霉素药物缓释系统(ADM-DDS)对兔眼人工晶状体植入术后后囊膜混浊(PCO)的抑制作用及其毒副作用,为临床应用提供实验依据。方法 自制聚乳酸(PLA)为载体的眼内植入型ADM-DDS,内含ADM 22μg。采用兔眼晶状体囊外摘出联合人工晶状体植入术的动物模型,术中将ADM-DDS植入15只兔眼晶状体囊袋内。术后临床常规检查,第4周行病理组织学及电镜检查。结果 实验组与对照组比较,晶状体后囊膜混浊减轻(t=2,P<0.01),Soemmering环面积减小(t=20.51,P<0.01),兔眼晶状体上皮细胞(RLECs)细胞核固缩坏死,胞浆凝集、空泡变性。两组之间的眼压、角膜内皮细胞形态及密度以及光镜下角膜、虹膜、睫状体、视网膜组织均无差异。结论 兔眼内植入ADM-DDS通过ADM缓释作用抑制了人工晶状体植入术后RLECs的增殖。ADM-DDS对兔眼角膜、虹膜、睫状体及视网膜无明显毒性。以PLA为载体的DDS将有可能成为临床上药物预防PCO的一种有效而安全的给药途径。     

两种AcrySof折叠式人工晶体植入后囊膜混浊的临床研究

目的：观察两种设计不同的AcrySof丙烯酸酯折叠式人工晶体(intraocular lens,IOL)对晶状体后囊膜混浊(posterior capsule opacification,PCO)的影响。方法：114例(114只眼)随机分为两组(1)试验组：59例(59眼)，植入一体式AcrySof折叠式IOL。(2)对照组：55例(55眼)，植入三体式AcrySof折叠式IOL。术后半年散大瞳孔观察Soemmering环和PCD情况。结果：瞳孔区PCD，试验组4只眼(6．8％)，混浊多为轻微皱褶。对照组11只限(20％)，试验组PCD明显少于对照组，差异有显著意义(P＜0．05)。两组术后Soemmering环边界均清晰而试验组更加明显，且撵周也形成明显的细胞增殖区。结论：一体式AcrySof折叠IOL具有独特设计的襻使晶状体后囊膜皱褶大为减少，远期PCO明显下降。     

阿霉素抑制兔眼晶状体上皮细胞增殖细胞核抗原表达的实验研究

目的 探讨人工晶状体植入术后阿霉素(adriamycin，ADM)抑制兔眼晶状体上皮细胞(rabbit lens epithelial cells，RLEC)增殖的作用及客观评价后囊膜混浊(posteriorcapsule opacification，PCO)的方法。方法 采用兔眼品状体囊外摘出联合人工晶状体植入术的动物模型，术中将携带ADM药物缓释系统植入l5只兔眼晶状体囊袋内。术后观察后囊膜混浊情况；术后第4周，链霉亲和素免疫组化法(strePt—avidin—biotin—enzyme comple，SABC)检测兔眼品状体上皮细胞的增殖细胞核抗原(pro1iferating cell nuclear antigen，PC—NA)的表达。结果 实验组与对照组比较，兔眼晶状体上皮细胞的PCNAP阳性表达下降，2组比较差别具有显著性意义。结论 ADM能有效抑制人工晶状体植入术后RLEC的增殖，免疫组化技术(SABC法)检测RLEC的PCNA的表达，为实验室客观评价PCO提供一种简便有效的方法。     

Livin在后发性白内障动物模型中的表达

目的:建立新西兰大白兔后发性白内障(posterior capsule opacification,PCO)动物模型,检测凋亡抑制因子Livin在PCO中的表达,从而探讨Livin在PCO形成过程中的作用。方法:选用健康新西兰大白兔30只,随机分为实验组(25只),分为A,B,C,D,E组,对照组(5只),实验组行右眼晶状体皮质吸出,分别于术后即刻;3,7,14,28d(每个时间点5只)对术眼行裂隙灯显微镜检查,并处死动物获取术眼晶状体后囊膜,对照组直接处死动物获取右眼后囊膜,采用逆转录聚合酶链反应(RT-PCR)和Western-blotting方法检测Livin在正常对照组及术后不同时间点PCO中的表达。结果:RT-PCR和Western-blotting在正常对照组及术后即刻A组均未检测到Livin的表达,实验组B,C,D,E术后不同时段的PCO组织中均可检测到不同程度Livin的表达,其中RT-PCR和Western-blotting均显示术后C组Livin表达较为明显,D组表达开始下降,但至E组仍有表达,B组表达最低。结论:Livin的表达在PCO的形成过程中具有相应的时相性,为进一步探索PCO的基因治疗提供了理论依据。     

5-Fu纳米粒涂层人工晶状体抑制兔晶状体后囊膜混浊的实验研究

目的 制备5-Fu纳米粒涂层人工晶状体(IOL)并探讨其对兔晶状体后囊膜混浊的抑制作用的有效性和可行性.方法 通过低能离子束表面氟离子注入技术使5-Fu纳米粒与IOL表面交联黏附形成涂层.取新西兰大白兔40只,随机分为A、B两组,每组20只,对左眼行超声乳化透明晶状体吸出术,对照组为A组,植入普通IOL;实验组为B组,植入5-Fu纳米粒涂层IOL.术后行裂隙灯显微镜、组织病理学及电镜检查.所有数据用SAS统计软件处理,前房闪光和晶状体后囊膜中央视区混浊程度均用Kruskal-Wallis秩和检验进行分析.结果 前房炎性反应:B组的前房闪光轻于A组,差异有统计学意义(x~2=11.245,P=0.024).两组兔眼的前房反应均在术后3 d至1周内缓解.晶状体后囊膜混浊:B组晶状体后囊膜的混浊程度轻于A组,差异有统计学意义(x~2=10.304,P=0.016).光学显微镜行组织病理学检查:A组眼内炎性反应较轻,B组无明显眼内炎性反应表现,A、B两组角巩缘结构及组织均无病理损害.扫描电子显微镜检查:A组见晶状体上皮细胞增生现象,B组未见明显晶状体上皮细胞增生.结论 兔眼透明晶状体超声乳化吸出术后植入5-Fu纳米粒涂层IOL,可有效抑制晶状体后囊膜混浊的发生,眼内毒性较小.     

囊膜抛光器超声乳化术中抛光的临床效果分析

目的:探讨白内障超声乳化术中运用抛光器行后囊膜抛光,对减少后囊膜混浊(posterior capsule opacification,PCO)的效果。方法:选择我院149例189眼白内障手术患者,其中82例104眼白内障患者在进行白内障超声乳化及人工晶状体植入术中运用抛光器进行后囊膜抛光处理,选择同期67例85眼未行后囊膜抛光患者进行对照。结果:术后6mo,抛光组后囊膜混浊发生11眼(10.6%),对照组后囊膜混浊发生23眼(27.1%)。两组比较有显著差异。术后12mo,抛光组后囊膜抛光组混浊发生17眼(16.3%),而对照组术后后囊膜混浊发生31眼(36.5%)。对照组显著高于抛光组。术后抛光组和未抛光组视力检查发现,1wk时两组之间无明显差异,而术后6mo和12mo时差异具有统计学意义(P<0.05)。结论:白内障超声乳化术中使用抛光器行后囊膜抛光安全有效,明显减少术后后囊膜混浊,能更好的提高患者视力。     

可生物降解载药性晶状体囊袋张力环抑制后发性白内障的研究进展

后发性白内障(posterior capsule opacification,PCO)是白内障摘出联合后房型人工晶状体植入术后导致视力下降的最常见远期并发症,是术后残留晶状体上皮细胞增生、迁移、上皮一间质转化,以及术后创伤和炎症反应的结果.术中植入含抑制晶状体上皮细胞增生药物的缓释系统或囊袋张力环均有可能降低PCO的发生.本文就药物、缓释系统、囊袋张力环在预防PCO中的应用加以综述,并构想一种可生物降解载药性晶状体囊袋张力环来预防PCO.     

不同边缘形状的人工晶状体与后发性白内障的临床研究

目的　观察直角边缘和弧形边缘折叠式人工晶状体植入术的临床效果 ,探讨手术因素 ,以及人工晶状体材料和边缘形状等因素对后发性白内障发生的影响。方法　观察 14 0例 (14 0只眼 )白内障患者超声乳化白内障吸除囊袋内折叠式人工晶状体植入术后的视力、晶状体囊袋和人工晶状体情况。直角边缘组 90只眼 ,术中植入疏水性丙烯酸酯直角边缘人工晶状体 ,随访时间 (14± 8)个月 ;弧形边缘组 5 0只眼 ,术中植入非疏水性丙烯酸酯弧形边缘人工晶状体 ,随访时间 (18± 8)个月。结果　晶状体后囊膜混浊直角边缘组 8只眼 (8 9% ) ,弧形边缘组 19只眼 (38 0 % ) ,两组比较差异有非常显著意义 (P <0 0 1)。环形撕囊口大小适中直角边缘组 76只眼 ,无晶状体后囊膜混浊发生 ;弧形边缘组 4 1只眼 ,其中 10只眼 (2 4 4 % )出现晶状体后囊膜混浊 ,两组比较差异有非常显著意义 (P<0 0 1)。环形撕囊口过大或偏位直角边缘组 14只眼 ,其中晶状体后囊膜混浊 8只眼 (5 7 1% ) ;弧形边缘组 9只眼 ,全部发生晶状体后囊膜混浊 (10 0 0 % ) ,两组比较差异有显著意义 (P <0 0 5 )。行激光晶状体后囊膜切开术直角边缘组 1只眼 (1 1% ) ,弧形边缘组 5只眼 (10 0 % ) ,两组比较差异有显著意义(P <0 0 5 )。结论　手术操作、人工晶状     

Preventing posterior capsule opacification by creating a discontinuous sharp bend in the capsule

PURPOSE: To clarify which factor--intraocular lens (IOL) design or material--contributes most to the inhibition of migrating lens epithelial cells (LECs). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: After phacoemulsification, an acrylic IOL with sharp optic edges was implanted in 1 eye and a poly(methyl methacrylate) (PMMA) IOL with an optic design similar to that of the acrylic IOL in the contralateral eye of 4 rabbits. RESULTS: The Miyake view and histopathological findings 3 weeks after surgery revealed that the lens capsule wrapped tightly around the optic edges, conforming to a distinctly sharp rectangular bend there with both IOL types in all rabbits. The migrating-LECs were inhibited at the site, and a massive Soemmering's ring cataract was formed. CONCLUSIONS: The discontinuous sharp capsule bend created by the sharp optic edges in both IOL types appeared to induce contact inhibition of the migrating LECs. The preventive effect of an acrylic IOL on posterior capsule opacification may be design dependent.     

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。     

Implantation of a single-piece,hydrophilic, acrylic,minus-power foldable posterior chamber intraocular lens in a rabbit model: clinicopathologic study of posterior capsule opacification

PURPOSE: To compare the extent of posterior capsule opacification (PCO) after implantation of a standard-power biconvex Centerflex intraocular lens (IOL) and a newly introduced biconcave high-minus-power Centerflex design in rabbit eyes. SETTING: The Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and the David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA. METHODS: Twelve rabbits had phacoemulsification and implantation of 2 foldable single-piece hydrophilic acrylic Centerflex posterior chamber IOLs. The right eyes received a standard-power (+21.00 diopters [D]) biconvex-optic lens and the left eyes, a minus-power (-7.00 D) biconcave-optic IOL. Formation of PCO was evaluated 3 weeks after surgery using the Miyake-Apple posterior photography technique. Histological sections from each globe were prepared to analyze capsular bag status and assess postsurgical intracapsular lens epithelial cell (LEC) proliferation, especially ingrowth of LECs across the visual axis. The data were analyzed using the Kruskal-Wallis 1-way analysis of variance for nonparametric measurements and the Mann-Whitney rank sum test. RESULTS: There was no significant difference in Soemmering's ring formation between the 2 IOL models. The biconcave minus-power IOL showed significantly lower central and peripheral PCO scores than the biconvex standard-power lens (P<.05). Pathological evaluations revealed that the effective site of blockage of LECs was at the truncated optic edge of both lenses, even in the presence of retained and/or regenerative cortical material. CONCLUSIONS: This study confirms the efficacy of a truncated IOL optic in helping reduce the incidence of PCO. Both IOL designs have optic geometries that create clear-cut barrier effects. However, the biconcave minus-power IOL, which has a thicker, square, truncated optic edge with a ridge that encircles the periphery of the optic for 360 degrees, appears to have an enhanced barrier effect, especially at the optic-haptic junction. This further minimizes the ingrowth of migrating LECs toward the visual axis.     

Selenium functionalized intraocular lenses inhibit posterior capsule opacification in an ex vivo canine lens capsular bag assay

The purpose of this study was to determine the inhibitory effect of selenocystamine coated intraocular lenses (IOLs) on the formation of posterior capsule opacification (PCO) in an ex vivo canine lens capsular bag assay. Selenocystamine was covalently bound to the surface of poly(2-hydroxyethyl methacrylate) (poly(HEMA)) discs. Three groups of canine lens capsules (6 coated IOLs (SeIOLs), 7 non-coated control IOLs and 8 empty capsules) were cultured for 10 days. During the culture period PCO was scored based on visual inspection of the capsules using phase contrast microscopy. On day 10 all the capsules were prepared for light microscopic examination and lens epithelial cells (LECs) were quantified. Proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA) and cleaved caspase-3 were examined by immunohistochemistry. Additionally, cell viability assays were performed on LECs cultured in tissue culture medium pre-incubated with either a SeIOL or control IOL. The viability assays demonstrated that no detectable cytotoxic leachables were associated with the functionalized IOLs. The central posterior capsule was free of cells underneath all SeIOLs, although large numbers of LECs populated the capsular periphery. Apoptotic cells were observed underneath the periphery of some SeIOLs. Both the PCO scores and LEC counts of SeIOL containing capsules were significantly lower than those of control group capsules (p < 0.01 and p = 0.0004, respectively).The use of selenium functionalized IOLs resulted in a significant reduction of PCO in this ex vivo model. Binding of selenocystamine to a foldable IOL may provide an effective method to prevent population of the central posterior capsule with LECs.     

Posterior capsule opacification in rabbit eyes implanted with hydrophilic acrylic intraocular lenses with enhanced square edge

PURPOSE: To evaluate the development of posterior capsule opacification (PCO) after implantation of single-piece hydrophilic acrylic intraocular lenses (IOLs) with an enhanced square edge. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: The standard 570H Centerflex (Rayner Ltd.) design was compared to 2 new designs with enhanced square edges: the 570E and the 570C. Ten IOLs of each type were implanted in a randomized manner by the same surgeon in 15 pigmented rabbits. After a follow-up of 3 weeks, the rabbits were killed and the eyes were analyzed from the posterior view. The intensity of central PCO, peripheral PCO, and Soemmering's ring formation was graded from 0 to 4. The area of Soemmering's ring was graded from 0 to 4 based on the number of quadrants involved. Other parameters analyzed were capsulorhexis coverage of the IOL edge and IOL centration and fixation. Results from the posterior view were complemented by histopathological evaluation. RESULTS: Posterior capsule opacification was lowest in the 570C group, highest in the 570H group, and intermediate in the 570E group. There was a statistically significant difference between the 3 groups in peripheral PCO (P = .039). No significant difference was found between the groups in the other parameters analyzed. When cell ingrowth occurred with the 570H, it started at the optic-haptic junctions, as observed during the clinical follow-up and confirmed by gross and histopathological analyses. CONCLUSIONS: The square optic edge is the most important IOL design feature for PCO prevention. However, it should be present for 360 degrees around the IOL optic to provide an effective barrier effect.     

超声乳化白内障吸除术后晶状体囊膜的变化

目的　观察超声乳化白内障吸除术后晶状体囊膜的变化及其对人工晶状体位置的影响 ,探讨术后晶状体前囊膜与人工晶状体光学面的最佳位置关系。方法　散大瞳孔 ,在裂隙灯显微镜下观察 12 7例 (14 1只眼 )以约 5mm直径连续环形撕囊行超声乳化白内障吸除折叠式人工晶状体植入术患者术后 3个月后晶状体前、后囊膜及人工晶状体位置的变化。结果　全部术眼晶状体前囊膜撕囊口边缘均形成白色环状Soemmering环 ,晶状体囊袋塌陷 ,前囊膜与人工晶状体光学面形成无夹持 (6 8只眼 )、部分夹持 (5 2只眼 )及完全夹持 (2 1只眼 ) 3种位置关系。其中完全夹持术眼晶状体后囊膜中央视轴区混浊的发生率 (47 6 % )明显高于无夹持术眼 (11 7% )和部分夹持术眼 (2 1 2 % ) ,差异均有显著意义 (P<0 0 5 ) ;无夹持术眼 (91 2 % )和完全夹持术眼 (81 0 % )人工晶状体正位率明显高于部分夹持术眼(42 3% ) ,差异均有非常显著意义 (P <0 0 1)。结论　超声乳化白内障吸除折叠式人工晶状体植入术后晶状体囊膜可发生不同变化 ,其中晶状体前囊膜撕囊口边缘全部位于人工晶状体光学面上 ,是保证术后晶状体后囊膜透明和人工晶状体正位的最佳位置关系。     

Evaluation of 3 modern single-piece foldable intraocular lenses: clinicopathological study of posterior capsule opacification in a rabbit model

PURPOSE: To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering's ring formation were evaluated 3 weeks after surgery using the Miyake-Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry. RESULTS: The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P <.05). There was no significant difference in Soemmering's ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material. CONCLUSIONS: The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.     

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.