Correlation between posterior capsule opacification and visual function before and after Neodymium: YAG laser posterior capsulotomy

PURPOSE: To investigate the correlation between visual acuity, contrast sensitivity, and contrast sensitivity with glare source (glare sensitivity), and the degree of posterior capsule opacification (PCO) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy. DESIGN: Prospective interventional case series. METHODS: Eighty-four patients (90 pseudophakic eyes) scheduled to undergo Nd:YAG laser capsulotomy were recruited. Visual acuity and contrast sensitivity with and without the presence of a circular glare source (using the contrast glare tester) were measured before and after Nd:YAG laser capsulotomy. The PCO density value was measured using a Scheimpflug videophotography system. The visual functions were statistically correlated with the PCO value. RESULTS: Before Nd:YAG laser capsulotomy, strong correlation existed between the PCO value and visual acuity (r = 0.728). Contrast sensitivity and glare sensitivity were also weakly correlated with the PCO value, but the correlation coefficients were smaller than that of visual acuity. After Nd:YAG laser capsulotomy, mean visual acuity, contrast sensitivity, and glare sensitivity at all visual angles improved significantly (P <.0001). After capsulotomy, no significant correlation was found between visual acuity, contrast sensitivity, or glare sensitivity and the PCO value. CONCLUSIONS: Before Nd:YAG laser capsulotomy, visual functions correlated significantly with the degree of PCO. Specifically, visual acuity has a stronger association with PCO than does contrast sensitivity or glare sensitivity and therefore should be considered to reflect most accurately the degree of PCO. After capsulotomy, these visual functions improve markedly and no longer have a significant correlation with PCO.     

人工晶状体眼晶状体后囊膜混浊对视功能的影响

目的:探讨人工晶状体眼晶状体后囊膜混浊对患者最佳矫正视力、对比敏感度、立体视觉及色觉等诸项视功能的影响。方法:对30例患者(35眼)超声乳化白内障摘除人工晶状体植入术后,发生后囊膜混浊(posteriorcapsuleopacification,PCO)的患眼及对侧眼进行最佳矫正视力、对比敏感度、立体视觉及色觉等项检查。对患眼施行Nd:YAG激光晶状体后囊膜切开术。术后1wk重复上述视功能检查,将术前术后检查结果进行配对比较分析,单眼患者与对侧眼进行比较。结果:Nd:YAG激光晶状体后囊膜切开术前患眼的LogMAR视力平均(0.43±0.33),术后LogMAR视力平均(0.08±0.12),术后视力较术前提高差异有极显著性(P<0.05)。患眼各空间频率的对比敏感度较术前均有明显提高,差异有统计学极显著性(P<0.01);而对侧眼术前最佳矫正视力、各空间频率对比敏感度与术后复查结果比较差异无显著性(P>0.05)。采用颜少明《立体视觉检查图》检测显示,激光后囊膜切开术前立体视觉阳性13例(43%),其中2例(7%)具有中心立体视,无立体视者17例(57%);Titmus立体视觉检查卡检查显示22例患者(73%)立体视阳性,其中4例有中心立体视(13%),无立体视功能者8例(27%)。术后颜氏《立体视觉检查图》和Titmus立体视觉检查卡检测的立体视阳性分别为24例(80%)和28例(93%),其中分别有11例(37%)和15例(50%)达到中心立体视,术后的立体视觉较术前改善差异有显著性(P<0.05)。术前全部患眼存在色觉异常,主要表现在蓝紫色及绿色辨别能力下降,术后色觉障碍有一定程度提高,但蓝紫色觉改善不明显。结论:人工晶状体植入术后后囊膜混浊不仅影响患眼视力的康复,还对对比敏感度、立体视锐度、色觉等多种视功能有不同程度的影响。Nd:YAG激光晶状体后囊膜切开术是治疗PCO,提高视力和改善视功能的有效方法。     

The effect of posterior capsule opacification on visual function

PURPOSE: To investigate how posterior capsule opacification (PCO) affects visual function in pseudophakic eyes. METHODS: One hundred and six eyes that had undergone uncomplicated phacoemulsification were recruited sequentially. Patients with surgical complications or other ocular disease were excluded. PCO was assessed by a digital retroillumination camera using a software program based on the analysis of texture in the image, and the percentage area within the central 3-mm zone of the posterior capsule was calculated. Visual function assessment included Early Treatment Diabetic Retinopathy Study (ETDRS) high- and low-contrast visual acuity, contrast sensitivity with the Pelli-Robson and CSV-1000 grating charts, and forward light-scatter by the direct-compensation method (van den Berg). RESULTS: The percentage PCO required for decline in high-contrast ETDRS was 78%; for low-contrast acuity and Pelli-Robson, 46%; for CSV-1000 contrast sensitivity, 38% to 51%; and for forward light-scatter, less than 1% PCO. CONCLUSIONS: Central PCO affects psychophysical test results with differing degrees of sensitivity. Forward light-scatter is the most sensitive, followed by contrast sensitivity and visual acuity.     

Association between intensity of posterior capsule opacification and visual acuity

PURPOSE: To investigate the correlation between the change in visual acuity and the difference in objective posterior capsule opacification (PCO) scores before and after neodymium:YAG (Nd:YAG) laser capsulotomy. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: Forty pseudophakic eyes of 35 patients with PCO of varying intensity were examined before and after Nd:YAG laser capsulotomy. Visual acuity was determined using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart at 4 m and the Holladay reading chart at 40 cm. The pupil diameter under reading conditions was measured each time. Digital retroillumination images of the posterior capsule were taken, and the corresponding area inside the pupil was evaluated using the Automated Quantification of After-Cataract (AQUA) automated PCO analysis program. The change in visual acuity and difference between PCO scores before and after Nd:YAG laser capsulotomy were calculated for all eyes. RESULTS: The mean AQUA score (scale 0 to 10) was 3.56 before and 0.13 after Nd:YAG laser capsulotomy. The mean ETDRS visual acuity score (logMAR scale) was 0.28 and -0.07, respectively. The correlation coefficient between the differences in PCO score and distance visual acuity was 0.61 and near visual acuity, 0.62. CONCLUSIONS: The objective PCO score obtained by an automated image-analysis program correlates well with the PCO-induced decrease in visual acuity when the central area (inside the pupillary aperture) of the posterior lens capsule was evaluated. Objective PCO assessment by automated image-analysis systems is, therefore, a valuable and clinically relevant method for clinical studies of the development and prevention of PCO.     

不同类型和部位后发性白内障对视功能的影响

目的应用计算机图像分析软件评价后发性白内障（posterior capsule opacification,PCO）的形态,以探讨不同类型、部位PCO对最佳矫正视力（best corrected visual acuity,BCVA）、对比敏感度（contrast sensitivity,CS）和眩光敏感度（glare sensitivity,GS）的影响。方法收集拟行激光后囊切开术的PCO患者61例（67眼）,充分散瞳,行详细眼科检查后,应用裂隙灯照相获取PCO后照法照片,使用PCO计算机分析软件（POCOman软件）对其进行形态学分析。同时分别测量所有患者激光后囊切开术术前及术后1周BCVA、CS、GS。分析不同类型、不同部位PCO对BCVA、CS、GS的影响。结果珍珠型PCO的BCVA、各频段CS和GS均低于纤维型PCO,且两者之间的差异有统计学意义（P〈0.05）。其中,4.0mm珍珠型PCO在低、中频段CS和中频段GS均低于中央2.0mm珍珠型PCO,差异有统计学意义（P〈0.05）;中央2.0mm纤维型PCO在中、高频段CS和低、中频段GS均低于中央4.0mm纤维型PCO,差异有统计学意义（P〈0.05）。中央2.0mm珍珠型PCO对BCVA的影响最为显著;中央4.0mm珍珠型PCO对CS和GS的影响最为显著。结论珍珠型PCO对BCVA、各频段CS和GS的影响大于纤维型PCO。珍珠型PCO在中央4.0mm区对视功能的影响大于中央2.0mm区;纤维型PCO在中央2.0mm区对视功能的影响大于中央4.0mm区。     

Influence on posterior capsule opacification and visual function of intraocular lens optic material

PURPOSE: To examine the influence of optic material on posterior capsule opacification (PCO) by comparing PCO and visual functions between eyes with an acrylic intraocular lens (IOLs) and those with a silicone IOL of the same optic design and with the same haptics. DESIGN: Randomized clinical trial. METHODS: One hundred patients scheduled for phacoemulsification surgery underwent implantation of an acrylic IOL (AMO Sensar; AR40e) in one eye and implantation of a silicone IOL (ClariFlex) of the same optic design and loops in the fellow eye. Eighty-nine patients (89%) remained for analysis. The PCO value was measured using the Scheimpflug videophotography system at one, three, six, 12, 18, 24, 30, and 36 months postoperatively. The incidence of eyes that required a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy was examined; visual acuity and contrast sensitivity with and without a glare source were also evaluated. RESULTS: The mean PCO value did not increase significantly during follow-up in either the acrylic or silicone IOL group. When comparing the groups, no statistically significant difference was found in the PCO or in the incidence of Nd:YAG capsulotomy, although both tended to be slightly better in the silicone group than in the acrylic group. There was also no significant difference between the groups in visual acuity or in photopic and mesopic contrast sensitivity with or without glare. CONCLUSIONS: When acrylic and silicone IOLs are of the same optic design and with the same haptics, the optic material does not influence the development of PCO enough to impair visual function.     

Self-assessed visual function for patients with posterior capsule opacification before and after capsulotomy

PURPOSE: To describe the functional outcome, as defined using the Catquest questionnaire, for patients with posterior capsule opacification (PCO) after capsulotomy. METHODS: A total of 47 patients with PCO were examined before and 1 month after capsulotomy. In addition to the ophthalmic examination, Catquest was completed and a digital image of the posterior lens capsule acquired. RESULTS: Capsulotomy resulted in a good level of benefit, as defined using Catquest, for 77% of the patients. No subgroup of patients who derived an exceedingly good or poor level of benefit was identified. Disabilities in daily life, satisfaction with vision and symptoms of glare improved from treatment (p < 0.001, p < 0.001 and p = 0.002, respectively). The results were comparable with the benefits of cataract surgery. CONCLUSIONS: Self-assessed visual function as defined using Catquest improved after capsulotomy for the vast majority of patients with PCO. No group of patients with exceptionally good or poor levels of benefit could be identified with certainty. However, the majority of those with a poor outcome were elderly individuals with ocular comorbidity. The overall functional results from treatment of PCO were very similar to those achieved after cataract surgery.     

Spontaneous visual improvement in the presence of posterior capsule opacification

We report a case of a patient who had reduced visual acuity due to posterior capsular opacification after extracapsular cataract extraction and posterior chamber lens implantation. Capsulotomy was not performed. Over the subsequent two years visual acuity returned spontaneously to normal.     

后发性白内障形态及对视功能影响临床分析

目的 通过对后发性白内障(Posterior Capsule Opacification,PCO)的形态学及其对视功能影响的客观综合评价,为临床激光后囊切开术提供指导意义.方法 选择61例(67只眼)后发性白内障拟行Nd:YAG 激光后囊切开术的患者,充分散大瞳孔(直径>6.00mm),先采用裂隙灯加前置镜行主观评价,再行裂隙灯眼底后部反光裂隙照相,所得数码图像使用POCOman软件进行分析,得出PCO的POCOman半客观评分.于Nd:YAG激光后囊切开术前、术后分别测量其最佳矫正视力(best corrected visual acuity,BCVA),同时使用自动眩光对比敏感度检查仪进行对比敏感度(contrast sensitivity,CS)和眩光对比敏感度(glare sensitivity,GS)的检测.分析统计不同类型、不同部位、不同程度PCO与视功能的关系.结果 珍珠型PCO在中心视力、各频段对比敏感度和眩光敏感度均低于纤维型PCO,且两者之间的差异有统计学意义(P<0.05);中央4.0mm珍珠型PCO在低、中频段对比敏感度和中频段眩光敏感度均低于中央2.0mm珍珠型PCO,差异有统计学意义(P<0.05).中央2.0mm纤维型PCO在中、高频段对比敏感度和低、中频眩光敏感度均低于中央4.0mm纤维型PCO,差异有统计学意义(P<0.05).中央2.0mm珍珠型PCO对最佳矫正视力的影响最为显著;中央4.0mm珍珠型PCO对对比敏感度和眩光敏感度的影响最为显著.随着PCO程度的增加,中心视力、全频段对比敏感度和全频段眩光敏感度逐渐下降.其间的差异有统计学意义.POCOman评分与最佳矫正视力、各频段对比敏感度、低中频段眩光敏感度的变化呈正相关(P<0.05),差异有统计学意义.结论 对后发性白内障行形态学及其对视功能受损的客观综合评价,可成为判断Nd:YAG激光晶状体后囊膜切开术手术时机和评价手术疗效的方法.     

人工晶状体后囊膜混浊激光治疗前后视功能的变化

目的探讨人工晶状体植入术后后囊膜混浊(PCO)对视功能的影响以及Nd:YAG激光治疗后的变化。设计前瞻性自身对照研究。研究对象接受超声乳化白内障摘除人工晶状体植入术57例(59眼)PCO患者。方法对57例(59眼) PCO患者行Nd:YAG激光治疗。于治疗前、后对患眼和对侧眼进行LogMAR视力、最佳矫正视力、对比敏感度、近距立体视锐度检查。主要指标 LogMAR视力、最佳矫正视力、对比敏感度、立体视锐度。结果激光治疗前患眼的平均LogMAR视力(0．22)及患眼各频区的对比敏感度值均较对侧眼显著低下;治疗后有明显提高(LogMAR视力0．00)。治疗后立体视阳性比率和达到中心立体视的比率,以及平均立体视锐度值均较治疗前有显著性改善。治疗后立体视锐度仍未达到正常者与最佳矫正视力低常、屈光参差及原有眼病有关。结论 PCO不仅影响患眼视力和对比敏感度,也影响立体视功能。Nd:YAG激光后囊膜切开术是治疗 PCO、恢复患者视力和重建正常立体视功能的有效手段。     

Posterior capsule opacification: comparisons between morphology, visual acuity and self-assessed visual function

PURPOSE: To investigate whether posterior capsule opacification (PCO) morphology, visual acuity (VA) and self-assessed visual function correlate, and to compare perceived visual disabilities with those of cataract patients with corresponding VA. METHODS: Twenty-one patients with PCO were examined before capsulotomy. In adjunct to the ophthalmological examination, the patients completed a Catquest questionnaire and a digitized retroillumation image was acquired. The images were analysed with the Evaluation of Posterior Capsule Opacification (EPCO) program. Data for visual function were compared with data from the National Swedish Cataract Register (NCR). RESULTS: The epco values were correlated with VA in the PCO eyes: the higher the epco score, the lower the VA. There were also correlations between the epco scores, satisfaction with vision, and perceived disabilities in daily life. Symptoms of glare were not significantly correlated with epco scores or with VA. Visual acuity in PCO eyes was better correlated with perceived disabilities and satisfaction with vision than VA in eyes with cataract. CONCLUSIONS: There was a significant correlation between epco scores and VA and between epco scores and Catquest. Consequently, the morphological method was related to the self-assessed visual function. Patients with PCO seemed to have more disturbed visual function, as defined by Catquest, than cataract patients with the same VA.     

Spontaneous visual improvement in the presence of posterior capsule opacification.

We report a case of a patient who had reduced visual acuity due to posterior capsular opacification after extracapsular cataract extraction and posterior chamber lens implantation. Capsulotomy was not performed. Over the subsequent two years visual acuity returned spontaneously to normal.     

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.     

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。     

Association between intensity of posterior capsule opacification and contrast sensitivity

PURPOSE: To investigate the correlation between change in contrast sensitivity (CS) and difference in objective posterior capsule opacification (PCO) score before and after Nd:YAG laser capsulotomy. DESIGN: Prospective interventional case series. METHODS: CS (Functional Acuity Contrast Test, or FACT, chart), distance visual acuity (Early Treatment Diabetic Retinopathy Study [ETDRS] chart), and pupil size of 30 pseudophakic eyes with PCO of varying intensity were measured before and after capsulotomy. Digital retroillumination images were taken, and the area corresponding to the pupil size was evaluated with an automated PCO analysis program known as AQUA. RESULTS: The correlation between change in PCO score and change in CS was highest (r = 0.85) for row B on the FACT chart and lowest (r = 0.09) for row E. The correlation with change in ETDRS visual acuity was 0.57. CONCLUSIONS: Objective PCO assessment by an automated image analysis system correlates well with PCO-induced loss of CS and is therefore an appropriate method for clinical studies on the development and prevention of PCO.