Nasisse M P, Dykstra M J, Cobo L M
College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
Graefes Arch Clin Exp Ophthalmol. 1995 Feb;233(2):63-70. doi: 10.1007/BF00241473.
Posterior capsule opacification (PCO) is the most common complication of lens extraction. Although intraocular lenses (IOLs) are thought to inhibit capsule opacification, the mechanisms by which they do this are poorly understood. This study was done to determine the effects of pseudophakia on secondary cataract and PCO in experimentally lentectomized dogs.
Twenty-four normal dogs were bilaterally lentectomized by phacoemulsification and unilaterally implanted with a plano-convex polymethylmethacrylate IOL. Secondary cataracts and capsule opacification were evaluated at weeks 1, 2, 4, 10, 14, and 20 after surgery by retrolillumination photography, light microscopy, and scanning and transmission electron microscopy.
The pattern of secondary cataract and PCO in dogs was found to be similar to that in other animal species. Production of new lens material was prominent in the equatorial region, and PCO resulted from fibrous metaplasia of lens epithelium and subsequent capsular fibrosis and wrinkling. The presence of an IOL did not prevent the posterior migration of epithelium, nor did it prevent fibrous metaplasia. The presence of an IOL did, however, minimize the capsule-wrinkling effects of fibroplasia and limit the space available for lentoid formation.
In pseudophakic eyes, IOLs influence secondary cataract formation by limiting the space available for lentoid formation and by maintaining a linear scaffolding for lens epithelial fibrous metaplasia.
后囊膜混浊（PCO）是晶状体摘除术后最常见的并发症。尽管人工晶状体（IOL）被认为可抑制囊膜混浊，但其作用机制尚不清楚。本研究旨在确定假晶状体对实验性晶状体摘除犬继发性白内障和PCO的影响。
24只正常犬经超声乳化双侧摘除晶状体，并单侧植入平凸聚甲基丙烯酸甲酯人工晶状体。术后第1、2、4、10、14和20周，通过后照像、光学显微镜以及扫描和透射电子显微镜评估继发性白内障和囊膜混浊情况。
发现犬继发性白内障和PCO的模式与其他动物物种相似。新晶状体物质的产生在赤道区域最为显著，PCO是由晶状体上皮的纤维化生以及随后的囊膜纤维化和皱缩所致。人工晶状体的存在并不能阻止上皮细胞向后迁移，也不能阻止纤维化生。然而，人工晶状体的存在确实将纤维增生的囊膜皱缩效应降至最低，并限制了晶状体样体形成的可用空间。
在假晶状体眼中，人工晶状体通过限制晶状体样体形成的可用空间以及为晶状体上皮纤维化生维持线性支架来影响继发性白内障的形成。
