The renal field has been struggling with this issue for more than 30 years that I know of. See a renal specialist and an opthalmologist as this generic problem is often associated with renal and retinal deterioration [hence the name renal-retinal syndrome]. If, as it sounds, you are in an early stage, it may be possible to slow or arrest it. If you are in the Brooklyn, NY, area, I recommend Dr. Eli Friedman who is a world authority on these problems. Tell him Eric sent you. I can give you his phone number.