Even though I'm relatively young, my eyesight is pretty terrible (inherited from my mother). I find that a brightly colored front sight works well for me. In my experience, painting the front sight with white fingernail polish and then painting over that with red fingernail polish makes it stand out very well against a black rear sight.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar