The visual acuity test uses Snellen charts to read letters at a specific distance.

• A. It measures color vision using Ishihara plates
• B. It measures intraocular pressure
• C. It uses Snellen charts to read letters at a specific distance
• D. It assesses peripheral vision

Answer: (C)

Visual acuity testing measures how clearly a person can see details at a distance. The Snellen chart is the standard tool for this: it uses lines of letters that get progressively smaller, and the patient reads them from a fixed distance (typically 20 feet or 6 meters). The smallest line a person can identify determines their distance visual acuity, often recorded as 20/20.

This is the best description because it directly describes reading letters on a Snellen chart at a specific distance to assess how sharp the vision is. The other options relate to different eye functions: color vision is tested with Ishihara plates, intraocular pressure is measured with tonometry, and peripheral vision is assessed with confrontation or perimetry tests.