Vision which cannot be corrected with ordinary ophthalmic lenses well enough so the person can perform every-day visual tasks, but which is not so poor as to qualify the person as legally blind; usually considered to be in the range from about 20/50 to 20/200. A person is considered legally blind if the corrected visual acuity is less than 20/200 in the better eye or if the total visual field subtends an angle no greater than 20° in its widest diameter.