I am paranoid about blindness, deafness, ect. what are ways to prevent this when i'm older?

Be healthy, checkups: I think you're asking how to prevent these issues even though you don't have them now. Decreasing vision and hearing can occur as people age, but some of the issues can be avoided with good prevention. Get yearly checkups with your primary doctor. If you feel you are having decreased vision or hearing, see the appropriate doctor. Being healthy now goes a long way to preventing issues later.