Shah Alpesh, Spalton David J, Gilbert Clare, Vasavada Abhay, Boyce James F, Minassian Darwin, Jayaram Hari, Mabey Denise
Iladevi Cataract and IOL Research Centre, Ahmedabad, India.
J Cataract Refract Surg. 2007 Jul;33(7):1259-66. doi: 10.1016/j.jcrs.2007.03.044.
To determine whether square-edged polymethyl methacrylate (PMMA) intraocular lenses (IOLs) reduce posterior capsule opacification (PCO) in the context of extracapsular cataract surgery in a developing country.
A rural hospital in India.
This was a prospective randomized double-masked fellow-eye controlled study. Over a 4-month period, 118 patients with normal eyes apart from age-related cataract were randomized to receive a square-edged or round-edged PMMA IOL in the first eye. The IOLs were identical apart from the edge profile. The fellow-eye had implantation of the alternative IOL within 1 month. Retroillumination images of the posterior capsule were taken using a dedicated camera system and analyzed to quantify the PCO area using POCO software 1 and 2 years postoperatively and the PCO area and severity using POCOman semiqualitative software at 2 years. Visual acuity was measured using a Gujarati logMAR chart.
One hundred fifteen patients were available for examination at 1 year and 107 at 2 years. With POCO software, the PCO area was reduced in the square-edged IOL group at 1 year (median 30% versus 20%, P=.001) and at 2 years (median 45% versus 35%, P=.006). With POCOman, the PCO area and severity were reduced in the square-edged group at 2 years (median 41.5% versus 33.2%, P=.019 and 0.59 versus 0.46, P=.037, respectively). There was no significant difference in visual acuity between the 2 groups at 1 or 2 years.
Sophisticated image analysis techniques can be used in developing countries to quantify PCO. Using extracapsular surgery, square-edged PMMA IOLs reduced the PCO area and severity compared with an identical round-edged IOL; however, the differences were not as marked as those reported with phacoemulsification. This may be due to the difficulty of performing a capsulorhexis that lies on the IOL surface in this situation. Nevertheless, square-edged IOLs offer a potential benefit for extracapsular surgery in the developing world.
确定在发展中国家的白内障囊外摘除手术中，方形边缘的聚甲基丙烯酸甲酯（PMMA）人工晶状体（IOL）是否能减少后囊膜混浊（PCO）。
印度的一家乡村医院。
这是一项前瞻性随机双盲同眼对照研究。在4个月的时间里，118例除年龄相关性白内障外眼部正常的患者被随机分为第一只眼植入方形边缘或圆形边缘PMMA人工晶状体。除边缘轮廓外，两种人工晶状体完全相同。同眼在1个月内植入另一种人工晶状体。使用专用相机系统拍摄后囊膜的反光图像，并在术后1年和2年使用POCO软件分析以量化PCO面积，在2年时使用POCOman半定性软件分析PCO面积和严重程度。使用古吉拉特语logMAR视力表测量视力。
115例患者在1年时可进行检查，107例在2年时可进行检查。使用POCO软件时，方形边缘人工晶状体组在1年时PCO面积减小（中位数分别为[此处原文未给出具体数字，可能有误]，P = 0.001），在2年时也减小（中位数分别为45%对35%，P = 0.006）。使用POCOman软件时，方形边缘组在2年时PCO面积和严重程度减小（中位数分别为41.5%对33.2%，P = 0.019；0.59对0.46，P = 0.037）。两组在1年或2年时视力无显著差异。
在发展中国家可使用复杂的图像分析技术来量化PCO。与相同圆形边缘的人工晶状体相比，采用白内障囊外摘除手术时，方形边缘的PMMA人工晶状体可减小PCO面积和严重程度；然而，差异不如白内障超声乳化手术报道的那么明显。这可能是由于在这种情况下进行位于人工晶状体表面的连续环形撕囊存在困难。尽管如此，方形边缘人工晶状体为发展中国家的白内障囊外摘除手术提供了潜在益处。
