RESUMEN
This research has been designed to analyze the risk factors of major eye diseases and the genetic alterations contributing to the manifestation of such disease. For this purpose, data was collected from 256 patients diagnosed by an ophthalmologist by using a specialized questionnaire. Blood samples were collected from 100 patients to perform a genetic investigation of cataracts. Whole genomic DNA was extracted from blood samples via the phenol-chloroform method. The purified DNA was used as the template for the amplification of about 400 bp fragments amplifying exons 1 and 2 of the CRYAA gene. The statistical analysis showed that 68% of individuals were blind due to cataracts. During molecular analysis, nucleotide sequences obtained have resulted in one silent mutation that occured at 20 positions in exon 2. It was replacing A>G which in turn substitutes the Lysine at position 70 for Arginine. It was interpreted by statistical analysis that this mutation did not result in a significant change in the CRYAA gene. In addition, protein analysis showed no significant changes in the structure of normal and mutated genes. At last, it is concluded that environmental risk factors play a major role in the studied diseases as compared to genetic factors. It is recommended to extend the study to a larger population to study all exons of the CRYAA gene as well as develop better estimates of the magnitude of the problems of visual loss and eye diseases in the Pakistani population.