Visual Acuity

A measure of the eye's ability to distinguish fine details and shapes at a given distance. Visual acuity is commonly expressed as a Snellen fraction (e.g., 20/20, 20/200) or in logMAR units used in clinical research. It is the primary metric for classifying levels of vision impairment and determining eligibility for assistive services. In digital accessibility, visual acuity directly influences the magnification level, font size, and display settings a person needs to read on-screen content comfortably.