OBJECTIVE Dietary antioxidant vitamins, in particular vitamin C, could play a role in preventing the onset or progression of age-related visual impairment. The aim of this study was to determine the plasma ascorbic acid levels in normal individuals and in senile cataract patients. METHODS The test group included 50 cataract patients, while the control group members were selected among medical staff and patients' companions after age matching with the test group. Questionnaire forms contained age, sex, and location of residency (urban or rural) inquiries. Five milliliters of drawn blood was centrifuged, and plasma ascorbic acid level was measured by spectrophotometer. Statistical analysis of plasma ascorbic acid concentrations were done by paired test. RESULTS The mean plasma ascorbic acid level in the test group was 0.96 +/- 0.08 mg/dl and 1.12 +/- 0.15 mg/dl in the control group. Ascorbic acid level in the test group was significantly lower than the control group and p value = 0.00001. Aging had a reverse relation with plasma ascorbic acid level in males, while it showed no significant alterations in females. Rural compared with urban and females compared to males showed higher levels of plasma ascorbic acid. CONCLUSIONS This study revealed that plasma ascorbic acid level in cataract patients was lower than normal individuals. Antioxidant vitamins, in particular vitamin C, found in Mediterranean fruits and vegetables, can help with the prevention of cataracts, which is a major health service burden in many countries.