All rights reserved. Two important measurements are visual acuity and visual field .
Visual acuity refers to the spatial detail that can be resolved by the eye.
It is most commonly measured using a letter chart called a Snellen chart. Therefore visual acuity meets the standard. An individual's visual field refers to vision off to the side, up and down. It is not necessarily related to visual acuity. Note that individuals who have lost one eye are not legally blind if the fellow eye is good.