Dylan is 11 now, and his eyesight is not great. He has dry eye, for which he has drops twice a day, plus cataracts, so they look cloudy. He can still see, but not as much as previously. Plus he is hard of hearing now. My last cocker went deaf, and we relied on hand signals, so whenever we trained Dylan with a command we used a hand signal with it, so he reacts to hands signals even without a command. Maybe Snoopy would do that, he would still be able to see exaggerated hand signals.
As for managing bad eyesight, make sure there is nothing low down he could hurt himself on. Were careful about where we let Dylan off the lead now. Other than that I don't know what else to suggest.
Love to snoopy

Lesley and Dylan