Yes, it is possible for people with dehydration feel blindness. Dehydration will affect eyesight, for without enough water, our body will not perform normally. Our lacrimal gland will become dry, which would make the vessel blood pass eyes more quickly without enough fresh oxygen, thus it could cause temporary eye dry and even blindness. what's more, dehydration will also result in dizziness which causes vision blur, shorter or longer focus length of eyesight, couple of images of a single object, etc. Usually it will recover after drinking enough water. But if you suffer dehydrayon and not recover after taking some water, you should consult the doctor.