According to this study:
In 10 human volunteers, the threshold of detection for irritation was about 0.1% when hydrogen peroxide was administered as drops directly to the eye (McNally, 1990).
Hydrogen peroxide reacts with Melanin pigments and turns it into colorless compound. Melanin is found in hair, skin and eye. H2o2 is already used to bleach hair to lighten it's color due to its effect on Melanin. this has already been many researches about turning melanin into colorless compound with h2o2 like this one, and there exist commercial compounds for achieving this result on hair. The question is why the same can't be done with eyes using extremely diluted h2o2 for long period of time.