Varma S D
Department of Ophthalmology, University of Maryland School of Medicine, Baltimore 21201.
Am J Clin Nutr. 1991 Jan;53(1 Suppl):335S-345S. doi: 10.1093/ajcn/53.1.335S.
Cataract is one of the major causes of age-dependent visual impairment and blindness. The geographic distribution of cataract is known to be associated with the intensity and duration of sunlight--especially of the ultraviolet frequency--at particular places. Exposure of animals and humans to oxygen has also been known to result in cataract formation. Studies described in this communication indicate that the ocular lens is physiologically damaged when exposed to an environment of active species of oxygen, commonly referred to as oxyradicals. Several photochemical and nonphotochemical models have been described. The results suggest that an intraocular generation of active oxygen may constitute a significant risk factor in the overall pathogenesis of senile cataracts. The cataractogenic effect of oxyradicals, however, can be thwarted by nutritional and metabolic antioxidants such as ascorbate, vitamin E, and pyruvate. These agents, therefore, may be useful for prophylaxis or therapy against cataracts.
白内障是导致年龄相关性视力损害和失明的主要原因之一。已知白内障的地理分布与特定地点的阳光强度和持续时间有关，尤其是紫外线频率的阳光。动物和人类暴露于氧气中也会导致白内障形成。本通讯中描述的研究表明，当眼晶状体暴露于通常称为氧自由基的活性氧环境中时，会受到生理损伤。已经描述了几种光化学和非光化学模型。结果表明，眼内活性氧的产生可能是老年性白内障总体发病机制中的一个重要危险因素。然而，氧自由基的致白内障作用可以被营养和代谢抗氧化剂如抗坏血酸、维生素E和丙酮酸盐所抑制。因此，这些药物可能对白内障的预防或治疗有用。
