Use of bipolar diathermy to prevent posterior capsule opacification(1)

PURPOSE: To determine the feasibility of using directed bipolar diathermy to eliminate or reduce the formation of new cortical lens material following phacoemulsification in a rabbit model. SETTING: Department of Research & Development, Bausch & Lomb Surgical, and Department of Ophthalmology, St. Louis University, St. Louis, Missouri, USA. METHODS: A rabbit model for posterior capsule opacification (PCO) was used. A continuous curvilinear capsulorhexis was performed followed by phacoemulsification to remove cortical lens material. In 2 experimental groups, modified bipolar instruments were used to apply diathermy to residual lens epithelial cells using an intracapsular or extracapsular method of application. Postoperative clinical examinations were at 1, 3, and 7 days and then weekly up to 60 days. Selected animals were followed for a longer period. Capsule integrity was evaluated by measuring the pressure required to rupture the capsule in similarly treated porcine eyes. RESULTS: Diathermy prevented PCO in 4 of 4 eyes in the intracapsular treatment group and 4 of 5 in the extracapsular group. Eyes remained free of new lens cortex for the life of the animal, which was as long as 18 months. New cortical material was detected after 35 days in 1 animal in the extracapsular group. Mean time for the formation of observable cortical material was 29 days +/- 5 (SD) in the control animals. Physical measurements did not detect a reduction in capsule integrity with diathermy treatment. The extracapsular treatment method resulted in fewer iris complications. CONCLUSIONS: Directed diathermy has the potential to eliminate secondary cataract formation with minimal damage to collateral tissues.     

Capsular bending ring to prevent posterior capsule opacification: 2 year follow-up

PURPOSE: To evaluate the preventive effect of a capsular bending ring on anterior and posterior capsule (PCO) opacification in a 2 year clinical study. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: This study comprised 60 patients with senile cataract (35 women, 25 men) with a mean age of 69 years. An open poly(methyl methacrylate) capsular bending ring with a truncated edge profile designed to create a sharp bend in the equatorial capsule was implanted in 1 eye of patients with a hydroxyethyl methacrylate intraocular lens (IOL). The contralateral eye, which acted as a control, received an IOL but no ring. Patients were examined 6 months (n = 52), 1 year (n = 48), and 2 years (n = 42) postoperatively. Anterior capsule opacification was determined by slitlamp evaluation. Anterior capsule shrinkage (area within the capsulorhexis) and PCO were evaluated and scored using a computer software package for image analysis. Posterior capsule opacification was also measured by the rate of neodymium:YAG (Nd:YAG) capsulotomies. RESULTS: Anterior capsule opacification and shrinkage were significantly less in eyes with the ring. The mean PCO score was 0.235 +/- 0.215 (SD), 0.287 +/- 0.200, and 0.398 +/- 0.248 with the ring and 0.530 +/- 0.190, 0.670 +/- 0.225, and 1.111 +/- 0.298 without the ring at 6 months, 1 year, and 2 years, respectively (P <.01 at each follow-up). An Nd:YAG laser capsulotomy was performed in 4 eyes with and 17 eyes without the ring after 2 years (P <.01). CONCLUSIONS: The capsular bending ring significantly reduced anterior capsule fibrosis and shrinkage as well as PCO. The ring may be useful in patients who are at high risk of developing eye complications from capsule opacification that require Nd:YAG laser capsulotomy, in those expected to have vitreoretinal surgery and photocoagulation, and in cases of pediatric cataract.     

Active oxygen processing for acrylic intraocular lenses to prevent posterior capsule opacification

PURPOSE: To evaluate active oxygen processing on the surface of acrylic intraocular lenses (IOLs) to prevent secondary posterior capsule opacification (PCO). SETTING: Department of Ophthalmology, Dokkyo Medical University School of Medicine, Mibu City, Tochigi, Japan. METHODS: Acrylic IOLs were prepared, and ultraviolet (UV)/ozone (UV/O3) or argon plasma was irradiated to the surface of the IOLs. Elemental analysis (electron spectroscopy for chemical analysis [ESCA]) of the IOL surfaces was performed to confirm surface modification. Changes produced by UV/O3 or argon plasma treatment were examined for fibronectin and lens epithelial cell (LEC) adhesion. To evaluate the PCO prevention by treated IOLs, 8-week-old albino rabbits were used. The rabbit eyes randomly had phacoemulcification and implantation of 3 different IOLs: the UV/O3-treated IOLs, argon plasma-treated IOLs, and the control IOLs. After 2 weeks, the rabbits were killed and their globes were dissected and fixed using formaldehyde 10%. The PCO was observed using light microscopy (DX51, ORIMPUS) after hematoxylin and eosin staining. RESULTS: Comparison of IOL surface composition by ESCA showed an increase in nitrogen content and hydroxyl substitute and carboxyl substitute groups on surfaces of treated IOLs. The fibronectin adhesion and the LEC adhesion on the UV/O3-treated and argon plasma-treated samples were increased. In the untreated group, there was statistically significant inhibition of PCO formation in the UV/O3-treated and argon plasma-treated groups. CONCLUSION: Active oxygen processing and argon plasma irradiation on the surface of IOLs was effective in preventing secondary PCO after cataract surgery.     

多聚赖氨酸与EDTA的交联物防治兔眼后囊膜混浊的研究

目的 观察在白内障术中应用多聚赖氨酸与EDTA的交联物对晶状体后囊膜混浊(PCO)的影响.方法 利用EDC将EDTA与多聚赖氨酸结合,制成交联物PLE.日本大耳白兔9只(18眼),随机分为3组.实验组在白内障囊外摘出术中分别于囊袋内注入药物:EDTA组注入EDTA 20 mmol/L;PLE组注入PLE其中含EDTA 10 mmol/L、NH2-10 mmol/L;对照组囊袋内不注入药物.术后用裂隙灯观察眼内组织的变化.28 d后处死兔子,摘除眼球,制作病理切片,光镜下观察晶状体上皮细胞(LECs)增生情况.结果 PLE组仅有少量细胞残留,未见细胞增生,其他组均可见不同程度的细胞残留及增生.结论 与EDTA相比,PLE可更有效地清除LECs.     

Double-masked prospective ocular safety study of a lens epithelial cell antibody to prevent posterior capsule opacification

PURPOSE: To evaluate the intraocular safety of an immunoconjugate (MDX-RA) developed to prevent posterior capsule opacification (PCO) in human eyes. SETTING: St. Thomas's Hospital Eye Department, London, United Kingdom. METHODS: Twenty-six patients had phacoemulsification and implantation of an intraocular lens (IOL). All were randomly allocated at the end of surgery to receive a 0.1 mL placebo or 0.1 mL of the immunotoxin MDX-RA intracamerally. Two doses of the drug were tested: 8 patients with a low dose (50 units), 9 patients with a high dose (100 units), and 9 with placebo. Follow-up at days 1, 14, 30, 60, 90, and 180 consisted of visual acuity measured by the Early Treatment of Diabetic Retinopathy Study test, contrast sensitivity, aqueous flare, specular microscopy of the IOL's anterior surface, and corneal endothelial counts. The percentage area of PCO was measured from retroillumination images of the posterior capsule. RESULTS: There was no decrease in corneal endothelial cell count in toxin-treated patients. Early postoperative flare, anterior chamber cell count, and corneal pachymetry were higher in toxin-treated patients. The median percentage area of PCO at 1 year was 32.0 in the placebo group, 3.8 in the low-dose group, and 7.4 in the high-dose group (P = .06). CONCLUSION: This prospective, randomized, placebo-controlled trial confirmed that MDX-RA is safe for intraocular use and is of potential value for further clinical trials of the prevention of PCO.     

白内障术后后囊膜混浊的发生因素

晶状体后囊膜混浊是白内障摘除联合后房型人工晶状体植入术后最常见的并发症,其发生率与人工晶状体的材料、镜片的式样,手术技术等因素均有关。新型的亲水丙烯酸和疏水丙烯酸AcrysofTM人工晶状体由于材料有良好的生物相容性及粘附性能,从而降低了后囊膜混浊的发生率。后凸型的人工晶状体、矩形锐利直角的光学边缘的人工晶状体、小切口白内障超声乳化摘除术、连续环形撕囊可以减少后囊膜混浊的发生率。     

Cytoskeletal drugs prevent posterior capsular opacification in human lens capsule in vitro

Background  

To determine whether the cytoskeletal drugs H-7 and Latrunculin B (LAT-B) inhibit posterior capsular opacification (PCO) in the cultured human lens capsular bag.     

后发性白内障相关因素的临床研究

目的观察超声乳化白内障吸除联合折叠人工晶状体植入术后后发性白内障(posteriorcapsuleopacification,PCO)发生的相关因素及其特点。方法随访观察394例(440只眼)白内障患者超声乳化白内障吸除联合囊袋内折叠人工晶状体植入术后的视力,用内置数码摄像头Zeiss120裂隙灯进行眼底后反光裂隙照相,转化成数码图像输入计算机,观察人工晶状体位置、连续环形撕囊和后囊膜混浊等情况。随访时间2～58个月,平均14个月。按照晶状体类型共分为6组Sensar组113例(123只眼),Acrysof三片组129例(157只眼),Acrysof一片组79例(84只眼),SC60B组23例(26只眼),硅凝胶组50例(50只眼)。获得的照片使用德国EPCO2000软件分析,对PCO程度进行评分并将各组进行比较分析。结果完全没有PCO的有19只眼(占4.32%),存在PCO的有421只眼(占95.68%),PCO波及瞳孔中央3mm的有274只眼(占62.27%)。按人工晶状体光学面材料分组的两组中,对应PCO数值进行比较,总分差异无显著性(t=1.470,P=0.143);按照襻的成角分组的四组中,所对应的PCO数值中1级混浊的数值比较,差异有显著性(F=4.054,P=0.007);按边缘设计不同分组的两组中,对应PCO数值比较,总分差异有显著性(t=3.763,P=0.0001);根据连续环形撕囊分组的3组中,所对应的PCO数值比较,总分差异有显著性(F=3.689,P=0.026)。结论后囊膜混浊的发生与人工晶状体材料无相关性;襻与光学面成角为10°的人工晶状体对PCO的早期形成有抑制作用;直角边缘设计可以减少PCO的形成;连续环形撕囊口完全覆盖人工晶状体光学面抑制了后囊膜混浊的发生几率。     

后发性白内障的研究进展

后发性白内障（posterior capsule opacification,PCO）是由于白内障术后残留的晶状体上皮细胞增殖、迁移、化生而形成的,严重影响术后视力的恢复,是现代白内障囊外摘出术后主要的并发症之一.因此,如何防治PCO一直是眼科研究的热点之一.本文就临床及实验室药物防治PCO两方面进行综述.     

Cytological factors relating to posterior capsule opacification following cataract surgery.

Simulated extracapsular cataract extractions on cadaver eyes were performed which demonstrated that the cells of the anterior capsule remain largely intact and that only a small amount of cortical lens matter remains postoperatively. Human lens epithelial cells from normal and cataractous lenses were grown in culture. There was no appreciable difference in growth rate between cells from normal and those from cataractous lenses or between equatorial and central capsule cells. The cells grew from the cut edges of the capsule, suggesting that release from contact inhibition is an important factor in stimulating proliferation. The daughter cells became increasingly abnormal and metaplastic in successive generations, but there was no evidence of differentiation into fibroblasts within the 35-day culture period, suggesting that a retinal growth factor may be involved with the fibrosis occurring in opacification of the posterior capsule. A small anterior capsulotomy will release fewer cells from contact inhibition and hence reduce cell proliferation after extracapsular cataract extraction.     

Systems of analysis of posterior capsule opacification

This paper demonstrates the wide variety of systems for the analysis of posterior capsular opacification (PCO). No single system has been proved to be a gold standard and it is difficult to comment on the advantages of one system over another with the limited current knowledge on the effects of PCO on vision. There are few studies that actually compare the different systems of analysis. Researchers must ensure that the systems they use for PCO analysis are objective and must give maximum consideration to ensuring potential systematic errors are reduced to a minimum. Further research is required into how the various types and locations of PCO affect vision and how well different systems of analysis perform.