Effect of intraocular lens convexity on posterior capsule opacification

A consecutive series of 248 eyes undergoing extracapsular cataract surgery and posterior chamber lens implantation were evaluated. One hundred eight eyes had the implant placed with the convex side posterior and 140 with the convex side anterior. The incidence of capsulotomy required in the convex posterior group was significantly less than in the convex anterior group, 17.6% versus 29.3% (P value less than 0.05). The type of posterior capsule opacification in the two groups was also different. In the convex posterior group, a smooth fibrous type of capsular opacification predominated; in the convex anterior group, epithelial proliferation and pearl formation as well as wrinkling of the capsule frequently occurred. The difference in opacification was reflected in the preoperative visual acuity: convex posterior 20/80, convex anterior less than 20/200 (P less than 0.05).     

Relationship between posterior capsule opacification and intraocular lens biocompatibility

The type of healing process that occurs in response to cataract surgery and intraocular lens (IOL) implantation is dependent on a complex set of variables. Their interactions determine whether or not optical clarity is restored as a result of this procedure. In this process, wound healing entails cells undergoing either epithelial-mesenchymal transition, resulting in the generation of fibroblastic cells and accumulation of extracellular matrix, or lenticular structure formation. Such desperate cellular behaviors are regulated by the localized release of different cytokines, including transforming growth factor beta and fibroblast growth factors, which can result in post-operative capsular opacification. Other factors affecting the biological and mechanical outcome of IOL implantation are its composition, surface properties and shape.     

Effect of intraocular lens design on posterior capsule opacification: an in-vitro model

BACKGROUND: The development of posterior capsule opacification (PCO) is one of the commonest complications of modern cataract surgery. The various designs of intraocular lenses (IOL) seem to exert a barrier effect on the proliferation and migration of lens epithelial cells and the following development of PCO. METHODS: We set up a cell culture model (advanced 3D capsular bag model) and investigated six differently designed IOL made of different materials as to their effect on cell proliferation. Proliferation and migration of the cells were analysed and documented over a period of 28 days. A cell viability test using the LIVE/DEAD kit (Molecular Probes) was carried out at the end of the investigation. RESULTS: In all tests, lens epithelial cells adhered to and migrated onto the capsular bag. During the culture period, lens epithelial cells migrated only to the optical rim of two of the implanted IOL. On the other four, lens epithelial cells migrated further and covered the whole optical area of the IOL. CONCLUSIONS: Certain lens designs seem to have a reducing effect on the development of PCO. Our advanced in vitro capsular bag model is a suitable cell culture model for the investigation of the reducing effect of various IOL on the development of PCO.     

Linear posterior capsule opacification with the AcrySof intraocular lens.

Intraoperative capsule striae are commonly seen after implantation of the AcrySof model MA60BM posterior chamber intraocular lens (IOL). Although the striae generally have no visual significance and tend to disappear with remodeling of the capsule-haptic interface, we report a series of patients who developed linear posterior capsule opacification (PCO) along persistent striae. The striae appear to create a channel that allows endothelial cells to bypass the barrier created by the squared-edge design of the IOL and migrate posteriorly in a linear pattern. The observation of linear PCO along channels created by capsule striae provide strong support for the theory that a sharp-edge design creates a barrier to posterior epithelial cell migration.     

The madurai intraocular lens study IV: posterior capsule opacification

PURPOSE: To estimate the cumulative incidence of posterior capsule opacification 4 years after surgery in patients who participated in the Madurai Intraocular Lens Study and had extracapsular cataract extraction with posterior chamber intraocular lens implantation. METHODS: In the Madurai Intraocular Lens Study, 1,700 patients with best-corrected visual acuity 20/120 or worse in the better eye had extracapsular cataract extraction with posterior chamber intraocular lens implantation, and 1,474 (86.7%) of these completed the 1-year follow-up examination. From this group of 1,474 pseudophakic patients, 400 were randomly selected for reexamination 4 years after the original surgery. The eye that was operated on was examined by an ophthalmologist who was involved in the 1-year follow-up examinations and posterior capsule opacification grading. A grading of I to III was used to reflect the degree of opacification. With grades II and III, posterior capsule opacification detectable with an undilated pupil was present in the central axis. RESULTS: Three hundred twenty-seven (81.8%) of the selected population were examined between October 1997 and December 1998. Thirty-four (8.5%) were confirmed as being deceased, and 39 (9.8%) were unavailable for follow-up. The median age was 60 years, and 57.2% were women. The 4-year incidence of grade II or III posterior capsule opacification, including eyes already treated with laser capsulotomy, was 13.1% (95% confidence interval [CI], 9.7% to 17.3%). Each year of increased age was associated with a decreased risk of posterior capsule opacification (odds ratio, 0.96; 95% CI, 0.92 to 1.00). Based on best-corrected visual acuity of 20/40 or worse without co-existing pathology, the 4-year incidence of posterior capsule opacification was 13.5%. CONCLUSION: Because patients with relatively mature cataracts routinely receive extracapsular cataract extraction with posterior chamber intraocular lens implantation instead of the traditional intracapsular extraction, the subsequent need for laser capsulotomy may be less than that anticipated, based on previous reports.     

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.     

Long-term effect of optic edge design in an acrylic intraocular lens on posterior capsule opacification

PURPOSE: To compare the posterior capsule opacification (PCO) inhibiting effect of the sharp posterior optic edge design of the Sensar OptiEdge AR40e intraocular lens (IOL) with that of the double-round edge design of the Sensar AR40 IOL over a period of 3 years. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: Fifty-three patients with bilateral age-related cataract (106 eyes) were included in this randomized prospective bilateral patient- and examiner-masked clinical trial with intraindividual comparison. Each study patient had cataract surgery in both eyes and received a Sensar AR40 IOL (anterior and posterior round optic edges) in 1 eye and a Sensar OptiEdge AR40e IOL (round anterior and sharp posterior optic edge) in the other eye. Follow-up examinations were at 1 week, 1 and 6 months, and 1, 2, and 3 years. Digital retroillumination images were taken of each eye. The amount of PCO was assessed subjectively at the slitlamp and objectively using automated image-analysis software (AQUA) 1, 2, and 3 years after surgery. RESULTS: The sharp-edged AR40e lens showed significantly less regeneratory and fibrotic PCO 1, 2, and 3 years after surgery. The mean AQUA PCO score was 2.18 for the AR40 and 1.00 for the AR40e lens after 1 year; 2.94 and 1.56 after 2 years, and estimated at 3.13 and 1.77, respectively, after 3 years (scale 0 to 10; P<.001). The neodymium:YAG laser capsulotomy rate was significantly higher in the AR40 group. The AR40e lens also led to less peripheral fibrotic PCO. There was no significant difference in complaints concerning edge glare between the groups. CONCLUSION: Compared with the AR40 IOL, the sharp posterior optic edge design of the Sensar OptiEdge AR40e IOL led to significantly less PCO 1, 2, and 3 years postoperatively. In contrast with most past studies on PCO-preventative factors, this study varied only 1 parameter, namely the optic edge design, and the main outcome measure (PCO) was assessed with an objective image-analysis system.     

Long-term effect of optic edge design in a silicone intraocular lens on posterior capsule opacification

PURPOSE: To compare the posterior capsule opacification (PCO) inhibiting effect of the round anterior and sharp posterior optic edge profile of the Clariflex silicone intraocular lens (IOL) [AMO Inc, Santa Ana, California, USA] with that of the double-round edge profile of the SI40 (Phacoflex; AMO Inc, Santa Ana, California, USA) silicone IOL over a period of three years. DESIGN: Prospective, randomized, double-masked, bilateral clinical trial. METHODS: The study took place at the Department of Ophthalmology, Medical University of Vienna, Austria. Fifty-two patients with age-related cataracts (104 eyes) were included in the study. Each patient received an SI40 IOL (round edges) in one eye and a Clariflex IOL with OptiEdge (sharp posterior optic edge) in the other eye. Follow-up examinations were at one week, one month, six months, and one, two, and three years. Digital retroillumination images were taken of each eye. The amount of PCO was subjectively assessed with the slit-lamp and objectively assessed by automated image analysis software (the computer program Automated Quantification of After-Cataract [AQUA]; Vienna, Austria) one, two, and three years after surgery. RESULTS: The Clariflex lens showed markedly less PCO at one, two, and three years after surgery. The mean AQUA PCO score was 1.39 for the SI40 and 0.56 for the Clariflex lens after one year, estimated at 1.64 and 0.57 after two years, and at 2.04 and 0.64, respectively, after three years (scale zero to 10; P < .001). The Nd:YAG laser capsulotomy rate was far higher in the SI40 group (Five cases vs one case at three years). CONCLUSIONS: The sharp posterior optic edge profile of the Clariflex silicone IOL led to marked and consistently less PCO than the round-edged SI40 IOL one, two, and three years after surgery.     

Effect of intraocular lens and anterior capsule opening type on posterior capsule opacification.

PURPOSE: To determine the effect of intraocular lens (IOL) type and anterior capsulectomy technique on the incidence of posterior capsule opacification. SETTING: Department of Ophthalmology, Medical Faculty, University of Ondokuz Mayis, Samsun, Turkey. METHODS: Three hundred two eyes of 294 patients were examined retrospectively after IOL implantation in the capsular bag performed between February 1991 and November 1996. Patients were divided into 3 groups according to IOL type: poly(methyl methacrylate) (PMMA); heparin-surface-modified PMMA (HSM PMMA); plate-haptic silicone. Envelope capsulectomy or continuous curvilinear capsulorhexis (CCC) was used. Mean follow-up was 27 months (range 12 to 33 months). RESULTS: Posterior capsule opacification developed in 47 cases (15.6%): 21.7% in the PMMA lens group after planned extracapsular cataract extraction (ECCE), 17.4% in the HSM PMMA lens group after planned ECCE, and 7.7% in the plate-haptic silicone lens group after phacoemulsification. Posterior capsule opacification occurred less in patients who had anterior capsulectomy using the CCC technique (11.5%) than in those having an envelope capsulectomy (24.5%) (P < .05). Posterior capsule opacification was significantly less in eyes with a capsular-bag-fixated plate-haptic silicone lens than in those with a PMMA or HSM PMMA IOL (P < .05). CONCLUSION: This study demonstrated that the anterior capsulectomy technique and the IOL type influence the incidence of PCO.     

Effect of intraocular lens optic design on posterior capsular opacification

Secondary capsular opacification is a common complication of extracapsular cataract extraction. We have done a retrospective study of 1,040 consecutive posterior chamber implants using four optic designs. The annual incidence of capsular opacification requiring capsulotomy was calculated to see if the optic design was a possible factor. The laser ridge and laser "peg" optics each had a cumulative capsulotomy rate of over 40.0% at three years and the convex-plano optic, over 40.0% at five years. Optics of plano-convex/biconvex designs had a cumulative capsulotomy rate of 5.0% at three years and 6.5% at five years. These results strongly suggest that capsular opacification is retarded when there is broad adhesion of the lens optic to the posterior capsule.     

人工晶状体材质和后表面形态对囊袋弯曲速度的影响

目的:客观评价晶状体材质、后表面形态对囊袋弯曲速度的影响.方法:非随机化临床试验.根据植入人工晶状体的不同,将老年性白内障患者分为三组,A1-UV组15例15眼,AO组15例15眼,IQ组15例15眼.分别在术后1d,1、2、4wk,通过裂隙灯观察术眼的上、下、左、右四个方位囊袋与人工晶状体边缘贴合程度.结果:术后1d囊袋弯曲系数,A1-UV组为3.34±0.22,AO组为3.00±0.19,IQ组为3.45±0.42,三组的囊袋弯曲系数的差异有统计学意义(x2=16.55,P＜0.05).对三组的临床疗效进行两两比较,发现A1-UV组和AO组的差异有统计学意义(x2=12.02,P＜0.05),A1-UV组和IQ组的差异无统计学意义(x2 =0.01,P＞0.05),AO组和IQ组的差异有统计学意义(x2=12.79,P＜0.05).术后1wk囊袋弯曲系数,A1-UV组为4.01±0.04,AO组为3.08 ±0.26,IQ组为3.50±0.44,三组的囊袋弯曲系数的差异有统计学意义(x2=29.07,P＜0.05).对三组的临床疗效进行两两比较,发现A1-UV组和AO组的差异有统计学意义(x2=28.64,P＜0.05),A1-UV组和IQ组的差异有统计学意义(x2=10.53,P＜0.05),AO组和IQ组的差异无统计学意义(x2=4.44,P＞0.05).术后2wk囊袋弯曲系数,A1-UV组为4.04±0.08,AO组为3.15±0.32,IQ组为3.53±0.47,三组的囊袋弯曲系数的差异有统计学意义(x2=27.49,P＜0.05).对三组的临床疗效进行两两比较,发现A1-UV组和AO组的差异有统计学意义(r=26.69,P＜0.05),A1-UV组和IQ组的差异有统计学意义(x2=11.28,P＜0.05),AO组和IQ组的差异无统计学意义(x2=3.27,P＞0.05).术后4wk囊袋弯曲系数,A1-UV组为4.04±0.08,AO组为3.16±0.36,IQ组为3.65±0.46,三组的囊袋弯曲系数的差异有统计学意义(x2=25.14,P＜0.05).对三组的临床疗效进行两两比较,发现A1-UV组和AO组的差异有统计学意义(x2=25.15,P＜0.05),A1-UV组和IQ组的差异有统计学意义(x2=7.11,P＜0.05),AO组和IQ组的差异无统计学意义(x2=5.52,P＞0.05).结论:囊袋弯曲速度受晶状体材质、后表面形态的共同影响.术后1d,影响囊袋弯曲速度的主要因素是人工晶状体的材质,疏水性丙烯酸酯人工晶状体可以加快囊袋弯曲速度.术后1 ～ 4wk,材质因素的影响减弱,影响囊袋弯曲速度的主要因素是人工晶状体的机械结构.具有高后凸形态的人工晶状体能够快速形成囊袋弯曲,加快囊袋与人工晶状体的黏附,减少晶状体上皮细胞向后囊迁移、增殖的时间,具有重要的临床应用价值.     

Rate of posterior capsule opacification in eyes with the Akreos intraocular lens

PURPOSE: To determine the rate of posterior capsule opacification (PCO) in eyes with an Akreos Adapt or Akreos Fit intraocular lens (IOL) (Bausch & Lomb) over a minimum follow-up of 18 months. SETTING: Department of Ophthalmology, Worthing and Southlands Hospital NHS Trust, Worthing, United Kingdom. METHOD: This was a retrospective analysis of 102 patients who had uneventful phacoemulsification with implantation of an Akreos Adapt IOL or Akreos Fit IOL from September 2001 to May 2004. Patients from a single surgeon's operating list were recruited into the study. Exclusion criteria included posterior subcapsular cataract, history of uveitis, diabetic retinopathy, glaucoma, and age-related macular degeneration. The protocol included the determination of logMAR best corrected visual acuity (BCVA) and PCO scoring using the Evaluation of Posterior Capsular Opacification System (EPCO 2000) by digital photography of the posterior capsule. The number of patients having a neodymium:YAG (Nd:YAG) capsulotomy was also recorded. RESULTS: The mean follow-up was 30 months +/- 10.3 (SD). The mean BCVA was 20/32 (0.2 logMAR). The mean EPCO score at the central 6.0 mm of the posterior capsule was 0.39 +/- 0.53 and at the central 3.0 mm, 0.18 +/- 0.40. The Nd:YAG capsulotomy rate was 8.8%. CONCLUSIONS: All patients had stable visual acuity with low rates of PCO 2.5 years after surgery. The PCO rate with the Akreos IOL was similar to that with other acrylic IOLs reported in the literature.     

Preventive effect of a second-generation silicone intraocular lens on posterior capsule opacification

PURPOSE: To compare the preventive effect of a second-generation silicone intraocular lens (IOL) on posterior capsule opacification (PCO) with that of a soft acrylic IOL. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: After phacoemulsification, a silicone IOL (PhacoFlex II) was implanted in 1 eye and an acrylic IOL (AcrySof) in the contralateral eye of 5 rabbits. RESULTS: The posterior view 3 weeks after surgery showed slightly more PCO in 3 eyes with the PhacoFlex II lens than in eyes with the AcrySof IOL, with the PCO obscuring the iris structures. In 2 eyes with an AcrySof IOL, slightly more PCO was seen. Histopathological examination revealed that a bend and complex folds in the posterior capsule were formed with both the PhacoFlex II and AcrySof IOLs. However, the capsular bend formed by the PhacoFlex II lens, which was caused by its blunt edge, was not as sharp as that with the AcrySof IOL and more PCO was seen in all eyes with a PhacoFlex II lens. CONCLUSIONS: Capsular bend formation does not necessarily require a sharp optic edge. A truncated optic rim of a certain thickness appears to form a bend. The capsule-bending does not appear to be an all-or-nothing effect. There seems to be a transition. That a capsular bend forms despite a blunt rather than a sharp optic edge may explain why the second-generation PhacoFlex II IOL prevents PCO better than first-generation and PMMA IOLs.     

Effect of different shape and material of intraocular lens on posterior capsule opacification

In this paper we compare 4 groups of intraocular lenses: PMMA, silicone, hydrogel, acrylic and their influence on posterior capsule opacification is discussed. The possible clinical consequences of different shape in optic part of intraocular lens is also described. This article contains also a short presentation of posterior capsule opacification mechanism and intraocular lens materials biocompatibility in in-vivo and in-vitro experiments.     

儿童人工晶状体瞳孔夹持合并后发性白内障的手术治疗

目的探讨儿童人工晶状体瞳孔夹持合并后发性白内障的治疗方法及疗效。方法对26例(26只眼)儿童人工晶状体植入术后人工晶状体瞳孔夹持合并后发性白内障进行超声截囊仪进行后囊切开、前部玻璃体切除、人工晶状体光学区后囊嵌顿术。观察手术并发症、术后眼部情况。结果 26只眼后发性白内障切除和人工晶状体光学部后囊膜夹持复位成功,术后患者随访期间均未出现视轴混浊,人工晶状体位置无偏离,位置稳定,仅出现短期的炎症反应,无其他严重并发症及晶状体后囊膜切开区再次混浊等并发症发生,术后视力有不同程度的改善。结论儿童人工晶状体瞳孔夹持合并后发性白内障进行手术治疗切除后发性白内障及人工晶状体复位是安全、有效的办法。     

硅凝胶人工晶状体预防后囊浑浊的Meta分析

目的 对硅凝胶人工晶状体预防后囊浑浊的作用进行系统评价。方法 检索MEDLINE，获得6篇以往发表的随机对照临床试验，根据临床和统计标准进行合并分析。以比值比来判定预防效果，并按照随机效应模型计算合并比值比。结果 总计6项研究的639例白内障符合入选标准。后囊浑浊的累计发生率分别为：硅凝胶人工晶状体组11．5％、聚甲基丙烯酸甲酯人工晶状体组26．5%。合并比值比为0．37[95％CI0．22，0．63]。结论 硅凝胶人工晶状体预防后囊浑浊的疗效显著。     

Effect of in-the-bag intraocular lens fixation on the prevention of posterior capsule opacification

PURPOSE: To compare the incidence of posterior capsule opacification (PCO) after extracapsular cataract extraction (ECCE) and phacoemulsification and to evaluate the role of posterior chamber intraocular lens (PC IOL) haptic fixation and biomaterial/design in reducing the incidence. SETTING: Postgraduate Institute of Medical Education and Research, Chandigarh, India; Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This study comprised 278 eyes of 263 patients having ECCE and 318 eyes of 297 patients having phacoemulsification with PC IOL implantation. Posterior capsule opacification leading to a decrease in Snellen visual acuity of 2 or more lines was considered visually significant. The presence of PCO and IOL haptic fixation were evaluated postoperatively using slitlamp biomicroscopy. Haptic position was noted as in-the-bag (B-B), 1 haptic in the bag and 1 in the sulcus (bag-sulcus [B-S]), or both haptics out of the bag (sulcus-sulcus [S-S]). In addition, the rate of visually significant PCO was compared among 3 IOL biomaterials: poly(methyl methacrylate), silicone, and hydrophobic acrylic.Results: Visually significant PCO occurred in 42.45% of eyes having ECCE and 19.18% of eyes having phacoemulsification (P <.001, chi-square test) after a mean follow-up of 2.4 years +/- 0.7 (SD). In both groups, visually significant PCO was significantly less in eyes with B-B fixation than in those with B-S or S-S fixation (P <.001). The rate of visually significant PCO in all eyes in the phacoemulsification group with B-B fixation was low (11.90%) and was significantly lower in eyes with a hydrophobic acrylic IOL (2.22%; P <.05, chi-square test). CONCLUSIONS: In-the-bag PC IOL fixation is required to consistently reduce the incidence of PCO. Thorough removal of lens substance, including hydrodissection-assisted cortical cleanup, and in-the-bag PC IOL fixation seem to be the most important factors in reducing PCO, regardless of surgical procedure or IOL type used. Intraocular lens biomaterial and design also help prevent PCO.