The Snellen chart is used in optometry to assess which of the following?

The Snellen chart is used in optometry to assess which of the following?

• A. Color vision.
• B. Depth perception.
• C. Peripheral vision.
• D. Visual acuity.

Answer: (D)

Visual acuity—the sharpness or clarity of central vision at a distance—is what the Snellen chart assesses. The chart presents letters in rows of decreasing size, and the patient reads the smallest line they can identify from a standard distance, usually 20 feet. The result is expressed as a ratio (20/x), where the numerator is the test distance and the denominator reflects the distance at which a person with normal vision could read the same line. This focuses on how well one sees details, not color, depth, or peripheral extent. Color vision tests evaluate color discrimination, depth perception tests assess stereoscopic vision, and peripheral vision tests measure the ability to see to the sides. Therefore, the Snellen chart is used specifically to measure visual acuity.

Visual acuity—the sharpness or clarity of central vision at a distance—is what the Snellen chart assesses. The chart presents letters in rows of decreasing size, and the patient reads the smallest line they can identify from a standard distance, usually 20 feet. The result is expressed as a ratio (20/x), where the numerator is the test distance and the denominator reflects the distance at which a person with normal vision could read the same line. This focuses on how well one sees details, not color, depth, or peripheral extent. Color vision tests evaluate color discrimination, depth perception tests assess stereoscopic vision, and peripheral vision tests measure the ability to see to the sides. Therefore, the Snellen chart is used specifically to measure visual acuity.