CATARACT CLASSIFICATION
CATARACT CLASSIFICATION
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DOI：
10.1007/bf01203680
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发表时间：
1994-01-01
影响因子：
1.4
通讯作者：
HOCKWIN, O
中科院分区：
文献类型：
--
作者：
HOCKWIN, O
眼睛晶状体混浊（通常定义为白内障）发生在晶状体的各个不同部分。因此，必须区分不透明的类型。对于流行病学研究，先决条件是根据白内障在晶状体内的定位以及混浊区域的大小和强度对白内障进行分类。过去使用了两种方法：1) 晶状体观察的主观方法（基于裂隙灯显微镜）和 2) 客观方法，根据 Scheimpflug 原理结合逆照技术，分别基于狭缝图像记录来测量晶状体透明度或晶状体不透明度。随着老化，镜片的透光度会发生相当大的变化。即使没有形成不透明性，UV-B/UV-A 和可见光范围内的波长的透射率也会减弱。单透镜层不同程度地受到这种现象的影响。这些变化也可能表明“白内障形成”的早期阶段，无法通过主观方法来辨别。然而，Scheimpflug 狭缝图像的光密度图像分析可以精确测量单晶状体层中的光散射，并能够及早识别透明度的干扰，这在白内障流行病学中尤其重要。鉴于我们目前的知识，通过对人群进行单一检查来进行患病率和/或发病率研究几乎不可能对多因素白内障过程中可能重要的风险因素进行评估。在这种情况下，进行重复检查的后续研究（队列研究）是先决条件。仅用于分类的“客观方法”就能够确保必要的再现性以及在发生可见（因此主观可识别）混浊之前测量晶状体透明度变化的可能性。关于 UV-B 辐射参与人类白内障形成过程的流行病学研究的系统程序需要应用客观方法进行白内障分类。
Opacifications of the eye lens - generally defined as cataracts - develop in various different parts of the lens. Therefore, one has to differentiate the types of opacities. For epidemiological studies it is prerequisite to classify the cataracts according to their localization within the lens as well as to the size and intensity of the opacified area. Two approaches have been used in the past: 1) subjective methods of lens observation (based on slit lamp microscopy) and 2) objective methods with measurements of lens transparency or lens opacity respectively based on slit image documentation according to the Scheimpflug principle combined with the retroillumination technique. With ageing, the light transparency of the lens is subjected to considerable changes. Even without the formation of an opacity the transmission of the wavelengths in the UV-B/UV-A and the visible range is diminished. The single lens layers are affected by this phenomenon to different degrees. These changes which might also indicate an early stage of 'cataract formation' cannot be discerned by subjective methods. The densitometric image analysis of Scheimpflug slit images, however, allows the exact measurement of the light scatter in the single lens layers and enables the early recognition of disturbances in transparency which is of crucial importance particularly in cataract epidemiology. In view of our present knowledge the evaluation of risk factors which might be of importance in multifactorial cataract processes will hardly be possible by carrying out prevalence and/or incidence studies involving a single examination of the population. In this case follow-up studies (cohort studies) with repeated examinations are prerequisite. The 'objective methods' for classification alone are able to ensure the necessary reproducibility and the possibility to measure transparency changes in the lens before visible (and therefore subjectively recognizable) opacifications occured. The methodical procedure with respect to an epidemiological study on the involvement of UV-B radiation in the processes of cataract formation in man requires the application of objective methods for cataract classification.