My cat can't judge distance anymore?

She has vision problems and cannot SEE the distance in order to judge it. This can be caused by lack of taurine in her diet, which results in vision deficiencies and eventually blindness. Ask your vet for taurine supplements, but sometimes pet owners allow their animals to eat another pets food. Cats should not eat dog food becuase it does not contain taurine, becuase dogs don't need it. Your cat should only be eating cat-specific food.