He apparently developed cataracts. But many impressionist paintings appear ‘indistinct’ in this way. (I’m not aware of any mention of Renoir having eyesight issues; nor of Turner, who is considered by many a forerunner of Impressionism.)
I think it was renior that lost his eyesight, or it got pretty bad anyways towards the end- if i recall correctly?
I love turner paintings too- such a cool style he had-