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北京市顺义县50岁及以上人群中盲患病率调查   总被引:79,自引:13,他引:66  
目的 调查北京市顺义县50岁及以上人群盲患病率,并与1985年调查结果相比较,以此评价近10余年该县实施防盲治项目的效果。方法 1996年9~11月采用整群随机抽样方法在顺义县抽取28个调查点,对50岁及以上人群进行视力和眼部检查。正式现场调查之前先进行预试验,并进行保证调查质量的重复性检验。结果 检录5555例中,受检人数为5084例,受检率为91.5%。以世界卫生组织视力损伤为标准,盲患病率为  相似文献
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准分子激光角膜切削术前后的角膜地形图分析   总被引:4,自引:0,他引:4  
了解准分子激光角膜切削术(photorefractivekeratectomy,PRK)前、后角膜表面形态变化并对切削区偏中心进行分析。方法应用计算机辅助的角膜地形图仪对80例(122只眼)PRK前、后角膜地形图进行检测和分析。结果术前角膜地形图的形态呈对称或非对称性蝴蝶结形者占75.4%;术后圆形或近似圆形者占63.9%。切削区偏离瞳孔中心的距离与术前屈光度无关。切削区偏中心距离越大,术后角膜散光增加及术后最佳矫正视力下降越明显。结论PRK前、后角膜地形图检查和分析能清楚地显示角膜表面形态变化及定量评估切削区偏中心问题。  相似文献
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Soluble lens crystallins from 6-10-week-old, galactose-fed, male Sprague-Dawley rats were analyzed by two-dimensional polyacrylamide gel electrophoresis at each of the five Sippel stages of cataractogenesis. Electrophoretograms were compared with similarly analyzed crystallins from comparably aged, chow-fed controls. Polypeptides were assigned to crystallin families and subfamilies on the basis of chromatographic fractionations with Sephadex G-200, superfine. Staining intensities of polypeptides from control lenses remained essentially unchanged throughout the experimental period, while those of the polypeptides from cataractous lenses showed non-uniform changes. Staining of the genomic gamma-crystallins increases up to at least stage 3; by stage 4, staining of gamma-chains, with perhaps those of gamma 5 and gamma 6 excepted, diminishes and in the total cataract, staining of all chains is further reduced. With possibly the addition of one chain, the total number of postsynthetically modified gamma-crystallins in cataractous lenses does not exceed that in the comparably aged normal lens. The genomic alpha- and beta-crystallin polypeptides are sustained close to normal levels up to stages 3 or 2, respectively, after which their gradually falling levels are accompanied by the generation of new species or elevated levels of existing post-translational species. An exception to this behavior is the rapid and total loss of beta B1a, a genomic subunit implicated in the aggregation of beta H-crystallins. Charge heterogeneity and variable pI displayed by beta B1a and other highly cationic beta- and gamma-crystallin polypeptides can be induced during isoelectric focusing and may be due to thiol group oxidation.  相似文献
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X Gong  N Du  J Chen  J Zhang  C Feng  L Chen 《眼科学报》1990,6(1-2):7-10, 48
The authors report the results of penetrating keratoplasty combined with cataract extraction in 50 cases. The rate of transparent grafts was 62% after an average follow-up of 19 months. 60% of the patients restored their vision to 0.1 and better. The rate of transparent grafts and visual improvement did not correlate with the mode of cataract extraction; however, the extracapsular procedure had less vitreous during operation than the intracapsular modality did. The authors recommend that the combined operation be adopted for patients with corneal opacity and cataract, and preferably using the extracapsular mode.  相似文献
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Lens lipid composition and lipid hydrocarbon chain structure change with age, region and cataract. Since the lens Ca(2+)-ATPase pump is important to the maintenance of calcium homeostasis and lens clarity, muscle sarcoplasmic reticulum Ca(2+)-ATPase was reconstituted with bovine lens lipids and dihydrosphingomyelin, the rare and major phospholipid of the human lens. Ca(2+)-ATPase activity was found to be about 5 times lower when the pump was reconstituted into dihydrosphingomyelin or lens lipids compared to native sarcoplasmic reticulum lipids. The addition of cholesterol to levels ranging from 13-53 mole%, had no affect on reconstituted Ca(2+)-ATPase activity. Ca(2+)-ATPase activity correlated with the degree of hydrocarbon chain saturation. The greater levels of saturation are a consequence of the high sphingolipid content in the reconstituted systems. These data support the hypothesis that changes in lens lipid composition or structure could affect Ca(2+)-ATPase activity in human lenses. Because the mechanisms governing Ca(2+)-ATPase activity in vivo are much more complex than in these simple reconstituted systems, this study represents an initial step in the elucidation of the relationships of endogenous membrane lipid composition-structure and function.  相似文献
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