Spontaneous regression of Elschnig pearl posterior capsule opacification

After extracapsular cataract extraction with in-the-bag intraocular lens implantation, a 72-year-old woman had reduced visual acuity from posterior capsule opacification (PCO) resulting from Elschnig pearl proliferation. No capsulotomy was performed, and the PCO decreased spontaneously over time, improving visual acuity and leaving a clear capsule.     

Posterior capsule opacification

Posterior capsule opacification (PCO) is the most common complication following primary cataract surgery. Advances in intraocular lens (IOL) designs that have reduced the amount of PCO following surgery have been made. The understanding of how the IOL design effects PCO has also advanced. Lenses that provide a mechanical barrier between it and the posterior lens capsule seem to inhibit PCO to a greater degree. Intracapsular rings are now being explored to test and enhance this barrier effect. Major advances in the elimination of lens epithelial cells at the time of surgery especially by pharmacologic means have also been made. An immunotoxin specific for human lens epithelial cells shows promise and is under latter phase clinical development.     

后发性白内障的防治新进展

后囊膜混浊(posterior capsule opacification,PCO)又称后发性白内障是现代白内障囊外摘出或超声乳化吸除联合人工晶状体植入术后最常见的晚期并发症,如何防治后发性白内障一直是眼科学者关注的焦点,并不断在此领域取得新的进展。拟对近年来后发性白内障防治中手术方式的改进、人工晶状体自身特性的影响、囊袋张力环的应用、密封囊灌洗技术的开展和基因治疗等方面的研究进展和发展趋势加以综述。     

后发性白内障的发病机制和药物防治的研究现状及前景

后发性白内障是现代白内障术后最常见的并发症。术后晶状体囊残留的晶状体上皮细胞的增殖、迁移、纤维化生是形成后发性白内障的主要原因。目前防治后发障的研究主要集中在药物除去或破坏残留晶状体上皮细胞。实验研究许多细胞毒药以及抑制晶状体上皮细胞生长和纤维化药物可以预防后发障,但目前临床上还没安全、有效的防治白内障方法。     

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.     

Posterior capsule opacification.

A complication of extracapsular cataract extraction with or without posterior chamber intraocular lens (PC-IOL) implantation is posterior capsule opacification. This condition is usually secondary to a proliferation and migration of residual lens epithelial cells. Opacification may be reduced by atraumatic surgery and thorough cortical clean-up. Clinical, pathological and experimental studies have shown that use of hydrodissection, the continuous curvilinear capsulorhexis and specific IOL designs may help reduce the incidence of this complication. Capsular-fixated, one-piece all-polymethylmethacrylate PC-IOLs with a C-shaped loop configuration and a posterior convexity of the optic are effective. Polymethylmethacrylate loops that retain "memory" create a symmetric, radial stretch on the posterior capsule after in-the-bag placement, leading to a more complete contact between the posterior surface of the IOL optic and the taut capsule. This may help form a barrier against central migration of epithelial cells into the visual axis. Various pharmacological and immunological methods are being investigated but conclusive data on these modalities are not yet available.     

结缔组织生长因子与后发性白内障的研究进展

后发性白内障(又称后囊膜混浊)已成为白内障术后视力再度下降,影响术后远期视力恢复的突出问题,主要是由于残留的晶状体上皮细胞向后囊膜移行、增殖形成。结缔组织生长因子(connective tissue growth factor,CTGF)是近年来倍受关注的促纤维化细胞因子。本文对近年来CTGF与后发性白内障关系的研究进展综述如下。     

后发性白内障预防的研究进展

后囊膜混浊是白内障囊外摘出联合人工晶状体植入术后最常见的并发症，术后残留的晶状体上皮细胞是其发生的关键因素。近年来国内外学者不断从手术方式的改进、人工晶状体的相关因素、囊袋张力环及染料对晶状体上皮细胞的影响、密封囊灌洗技术的应用等方面来防治后发性白内障，本文主要对近几年的研究进展加以综述。     

晶状体囊袋张力环在预防后囊膜混浊中的应用

后囊膜混浊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并发症之一 ,而术中植入囊袋张力环可有效地降低后囊膜混浊的发生 ,我们就囊袋张力环在白内障术中的应用及发展情况加以综述     

不同的给药途径防治后发性白内障

后发性白内障是白内障囊外摘出联合人工晶状体植入术后最常见的并发症,术后残留的晶状体上皮细胞是其发生的关键因素,防治后发性白内障最重要问题是抑制晶状体上皮细胞增殖和迁移,这类似于肿瘤的治疗,因此,选择最佳给药途径以维持药物有效浓度并减少其毒副作用,是研究的难点,我们就防治后发性白内障的药物的给药途径进行综述。     

Fibrosis adjacent to the anterior lens capsule after extracapsular cataract extraction

Fibrosis, contraction and opacification of the posterior lens capsule after extracapsular cataract extraction, is a frequent complication following cataract surgery. In these cases, cellular proliferation occurs along an intact posterior capsule. We report a case of fibrosis adjacent to the anterior lens capsule, where cellular proliferations and collagen production completely sealed the anterior capsulotomy three months after a routine extracapsular cataract extraction with implantation of a posterior chamber lens. The fibrosis led to contraction of the remainder of the anterior capsule, significantly reducing vision. Examination of the excised material by light and electron microscopy, and immunohistochemistry, revealed cells with features compatible with fibrocytes that did not stain positive for cytokeratin. The cells were situated in a dense collagen matrix. An anterior capsulotomy that is too small prevents sufficient removal of lens epithelium, and may be a risk factor for this complication.     

Posterior capsule opacification: a review of the aetiopathogenesis, experimental and clinical studies and factors for prevention

Posterior capsule opacification (PCO, secondary cataract, after cataract) is a nagging postsurgical complication following extracapsular cataract surgery (ECCE) and intraocular lens (IOL) implantation. PCO should be eliminated since it has deleterious sequelae and Neodynium: Yttrium Aluminium Garnet (Nd: YAG) laser treatment often is an unnecessary financial burden on the health care system. PCO following cataract surgery could be a major problem, since patient follow-up is difficult and the Nd:YAG laser is not always available. Advances in surgical techniques, IOL designs/biomaterials have been instrumental in bringing about a gradual and unnoticed decrease in the incidence of PCO. We strongly believe that the overall incidence of PCO and hence the incidence of Nd:YAG laser posterior capsulotomy is now rapidly decreasing - from 50% in the 1980s and early 1990s to less than 10% currently. Superior tools, surgical procedures, skills and appropriate IOL designs have all helped to significantly reduce this complication. In this article, we review the aetio pathogenesis, experimental and clinical studies and propose surgical and implant-related factors for PCO prevention. Careful application and utilisation of these factors by surgeons could lead to a significant reduction is secondary cataract, the second most common cause of visual loss worldwide.     

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.     

Posterior capsule opacification in pseudophakic eyes--etiopathogenesis, clinical picture, possibilities of prevention and therapy

Posterior capsule opacification (PCO) is a late complication after the cataract surgery, currently occurring most often. The epithelial cells which migrate to the surface of the posterior capsule participate in the mechanism of PCO formation. Clinical opacification of the posterior capsule appears as the foggy form, creasing, pearl mass and fibrosis. PCO can be cured by laser or surgical capsulotomy. The factors influencing a size and intensity of PCO are as follows: age of patient, other diseases, method of surgery and type of the implanted artificial intraocular lens. Prevention against PCO during surgery should include accurate hydrodissection, removing of cortical mass, polishing of the capsule and intracapsular fixation of the lens. It is necessary to carry out further studies on possibilities of PCO prevention.     

Posterior capsule opacification: a specular microscopic study

Posterior capsule opacification following extracapsular cataract extraction is a manifestation of migration of lens epithelial cells onto the posterior capsule. Collagen production by these epithelial cells results in white "fibrotic" opacities. These cells have myoblastic features and their contraction produces wrinkling of the posterior capsule resulting in visual distortion. A high magnification, in vivo specular microscopic study of human posterior capsules following extracapsular cataract extraction is described. In vivo findings correlate with histopathologic observations made on opacified posterior capsules. Lens epithelial cells migrate onto the posterior capsule and produce basement membrane and collagen. Collagen production is associated with a spindle-shaped appearance of the hyperplastic cells. This technique is useful for clinical research on posterior capsule opacification, including the evaluation of interventions designed to treat or prevent this complication.     

Posterior capsule opacification. Part 2: Clinical findings

The incidence of posterior capsule opacification (PCO), the most common complication of modern cataract surgery with intraocular lens implantation, seems to have decreased slightly as a result of improved surgical and cortical cleanup techniques. However, the reported incidence is still significant. The diverse findings on PCO are the result in part of studies using different criteria to clinically judge and quantify the condition. In addition, the influence of intraocular and systemic factors are only now being identified. This second of a 2-part review of PCO focuses on (1) less subjective morphological and patient-dependent means to evaluate and quantify PCO; (2) the influence of ocular factors on PCO; (3) the influence of systemic factors on PCO; (4) available means and approaches to prevent or delay PCO.     

Effect of the laser ridge on posterior capsule opacification

The most common complication of extracapsular cataract extraction is posterior capsule opacification, which appears to result from the proliferation of anterior lens epithelium onto the posterior capsule. The presence of a posterior chamber intraocular lens has been shown to decrease the incidence of posterior capsule opacification, possibly by a barrier mechanism. This retrospective clinical study compares the effect of two different lens designs (with and without a laser ridge) on posterior capsule opacification requiring Nd:YAG laser posterior capsulotomy. Twenty-one of 101 patients (20.8%) with nonridged lenses required Nd:YAG laser posterior capsulotomies versus 13 of 86 patients (15.1%) with ridged lenses. Although these data showed a clinical benefit from using a ridged lens, no statistical difference in the incidence of posterior capsulotomy was noted. Further evaluation of capsular-optic surface apposition is needed.     

Pharmacological attempts to reduce posterior capsule opacification after cataract surgery – a review

Reduction of posterior capsule opacification (PCO) after cataract surgery has been achieved since the general acceptance of posterior chamber intraocular lens implantation 30 years ago. Attention to surgical technique on the one hand and changes in lens design and materials on the other have synergistically reduced the incidence of PCO to less than 5% at 5 years. But lens epithelial cells still proliferate and pharmacological prevention has been largely unsuccessful so far. Any agent must be toxic to these lens epithelial cells without being toxic to the corneal endothelium. This review looks at many substances that have been tried and a few that have been partly successful without yet entering clinical practice. Possibilities for future clinical research are canvassed.     

Spontaneous regression of Elschnig pearl posterior capsule opacification

A 60-year-old man with senile cataract had phacoemulsification and implantation of a single-piece acrylic intraocular lens (IOL) in July 2000. There were no intraoperative or short-term postoperative complications, and the visual acuity was 20/20 on the day after surgery. In February 2002, 19 months postoperatively, posterior capsule opacification (PCO) extending from the base of the IOL loops was observed. Capsulotomy was not performed, and the PCO regressed spontaneously between April 2003 and March 2005. This is the first documented case of spontaneous PCO regression after phacoemulsification and IOL implantation.     

晶状体囊抛光及透明质酸酶预防囊的浑浊

目的探讨晶状体囊抛光并囊袋内注射透明质酸酶预防囊的浑浊和后发性白内障的作用及安全性.方法年龄相关性白内障70例80眼,按常规进行超声乳化吸出人工晶状体植入术.治疗组40眼水分离时用含透明质酸酶1000 IU的必施（BSS）进行,乳化吸出晶状体核和皮质后在黏弹剂的保护下,囊袋内注入含透明质酸酶500IU的BSS,2分钟后用抛光针尖进行晶状体囊抛光,然后注吸清除上皮细胞碎屑,囊袋内植入人工晶状体.对照组40眼则用同等量BSS进行水分离,仅行后囊抛光.术后18月随访,进行角膜内皮、眼底及视网膜电图等检查,并对前、后囊浑浊的情况进行分级.结果术后18月治疗组前、后囊膜浑浊的发生率与对照组相比,差异有统计学意义.角膜内皮损失率与对照组相比,差异无统计学意义.两组眼底检查和视网膜电图检查显示视网膜功能正常.结论晶状体囊袋内注射透明质酸酶联合晶状体囊抛光可以预防囊的浑浊和后发性白内障发生,且眼内应用安全.