ABO NOCE Basic Opticianry

Answer: A - Visual acuity is the measurement of the visual processing system to determine visual performance.

Visual acuity is determined by being tested viewing a Snellen chart at the distance of 20 feet. Normal range for a person with accurate vision is the ability to see certain size objects clearly at 20 feet. Deviations from this usually mean that you need corrective lenses in order to see objects clearly at that distance.