Definition

1. Noun:
   • Normal visual acuity: The standard measurement for clear, sharp vision at a distance. It is determined by the ability to correctly identify letters or symbols on a standardized eye chart from a distance of 20 feet.

Usage

• The term "twenty-twenty" is used almost exclusively to describe the clarity or sharpness of a person's distance vision. It is a clinical term commonly used by optometrists and ophthalmologists.
• It is typically written with a hyphen: . In medical notation, it is often symbolized as "20/20".

Examples

• Noun:
  • After getting new glasses, her vision was restored to twenty-twenty.
  • The doctor confirmed that the patient has 20/20 vision.
  • Very few people have perfect twenty-twenty vision without any correction.

Advanced Usage

• "20/20 hindsight": This is a common idiomatic expression meaning the perfect understanding of a situation or event it has happened. It plays on the idea of perfect, clear vision looking back in time.
  • With 20/20 hindsight, we can see that investing in that company was a mistake.

Variants and Related Words

• 20/20 (notation): The standard numerical and symbolic notation for "twenty-twenty" vision.
• Visual acuity: The formal medical term for the clarity or sharpness of vision, which "twenty-twenty" is a measure of.
• Snellen chart: The name of the specific eye chart used to measure twenty-twenty vision.

Synonyms

• Normal vision
• Perfect vision (in a colloquial, non-medical sense)
• Standard vision

Related Idioms

• 20/20 hindsight: As described in Advanced Usage, this idiom is directly derived from the term and is its most common figurative use. It criticizes the act of judging past decisions with knowledge only available in the present.
  • It's easy to say we should have left earlier with the benefit of 20/20 hindsight.

Noun

1. normal visual acuity, as measured by the ability to read charts at a distance of 20 feet