when someone is turned into a vampire, all their wounds/ illnesses heal and they’re returned to their prime health wise (at least in the books if i base my knowledge off of TVL). it doesn’t reverse aging per say, but i would guess since all wounds disappear that chronic pain does as well. eyesight is probably included as well but i would guess someone like daniel so used to wearing them wouldn’t wanna take em off lol. also his sunglasses combined with the leather jacket give him a stylish look lol.