Aspirin effect on cataract formation in patients with rheumatoid arthritis alone or combined with diabetes.

The prevalence of cataracts is significantly lower in patients with rheumatoid arthritis receiving aspirin (mean of 2,700 mgs daily for an average of 10.4 years) as compared to the matched population not receiving aspirin. Similarly, fewer cataracts were found among a population with diabetes and rheumatoid arthritis receiving aspirin (mean of 2,340 mgs daily for an average of 8.8 years) as compared to the matched population on no aspirin. The effects of aspirin on cataract formation may result from 1) lowering of plasma tryptophan levels and increased excretion of tryptophan metabolites, 2) inhibition of aldose reductase and sorbitol formation in the diabetic lens, 3) inhibition of tryptophan or kynurenine binding to lens protein.