Being blind means you cannot see anything, including light.
If you are partially blind, your eyesight is limited. You might, for instance, be unable to tell forms of objects apart or have a fuzzy vision. You cannot see at all if you are completely blind.
A vision that is severely impaired is referred to as legal blindness. A legally blind person can see what someone with normal vision can see from 200 feet away, but only from 20 feet.
If you suddenly lose your vision, get medical help straight away. Have someone take you to the emergency room so you can get treated. Stop waiting for your vision to come back.
Getting therapy right away could improve your chances of getting your sight back, depending on what caused it. Surgery or drugs may be used as treatment.