Optotype

Part of speech: noun

Definitions

1. A symbol or character specifically designed for assessing visual acuity in eye examinations
2. A standardized figure or letter employed during eyesight tests to measure clarity of vision
3. A designated visual mark utilized by eye care professionals to evaluate how well a person can see

Etymology: "Optotype" is built from two Greek-derived pieces: "opto-", from Greek "optos" meaning "seen" or "visible" (the root behind "optic" and "optician"), and "-type", from Greek "typos" meaning "impression" or "figure," which gives us words like "type" and "prototype." Put together, the term names something whose purpose is to be seen as a distinct impression. In practice, an optotype is the standardized symbol on an eye chart, such as a letter, a number, or a shape like a Landolt C, that a patient is asked to identify at a set distance. Each one is designed so that its details fall within a precise visual angle, which is what lets the chart measure acuity consistently from one test to the next.