Visual Impairments. KNR 270. Visual Impairments. What is visual acuity? Amount of detail that can be seen Clearness What is visual field? Entire area that can be seen at one time with fixed eyes 180 degrees. Visual Impairments. What do you think about when you hear that someone is blind?
At 20 feet, the person with 20/20 vision sees the stop sign clearly. At 20 feet, the person with 20/40 vision sees the stop sign as if they were 40 feet away.
Human (Sighted) Guide