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Cataract, the lens capacity, is well recognized as a major cause of visual disability and blindness throughout the world (Spector, 1974). Cataract is a disease of old age and three fifth of all people between ages of 65 and 74 show beginning sign of cataract (Langone, 1984). About 17 million people in both developed and developing countries suffer from cataract. In United States, about 650,000 operation are performed per year. In countries located in tropical areas like Egypt, Tunisia, Nepal, Pakistan and India, cataract accounts for higher proportion of blindness as compared to the West. Especially in Pakistan and India, cataract formation is more commonly observed in younger patients (Chatterjee, 1973). Many factor cause cataract, such as genetic and metabolic disorders, intraocular diseases, chemicals and radiations, dietary deficiencies, diabetes and old age. So far, senile cataract or cataract due to age is most common and its formation is attributed to various factors superimposed by aging process.
For understanding the lens opacity, it is important to study lens and its relevant fluids, i.e., plasma and aqueous humor. Most forms of cataracts are clearly due to changes in the chemical environment of the lens (Bito, 1977). Since senile cataract develops over a period of years or decades, it can be expected to result from very subtle changes in intraocular composition. |
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