Vision is a broader term than visual acuity or eyesight. Depending on which dictionary or other resource you check, it can mean "ability to see," "the sense of seeing," "vision," "range of sight" or "view." Often, the terms "eyesight" and "visual acuity" are used interchangeably. The exact definition of "eyesight" is difficult to pin down. Visual acuity typically is quantified with Snellen fractions (see "What is 20/20 Vision?" below). Only light that is focused on a very small and highly sensitive portion of the central retina (called the macula ) influences visual acuity measurements obtained during an eye exam.įIND AN OPTICIAN: if you're concerned about your vision, visit an optician near you. The ability of the brain to interpret information received from the eyes The sensitivity of the nerves in the retina and vision centres in the brain How accurately the cornea and lens of the eye focus light onto the retina Three major physical and neurological factors determine visual acuity: Objects that are similar in brightness to their background Visual acuity also is tested under high contrast conditions - typically, the letters or numbers on the eye chart are black, and the background of the chart is white.Īlthough visual acuity testing is very useful to determine the relative clarity of your eyesight in standardised conditions, it isn't predictive of the quality of your vision in all situations.įor example, it can't predict how well you would see: Visual acuity is a static measurement, meaning you are sitting still during the testing and the letters or numbers you are viewing also are stationary. Visual acuity is the clarity of your eyesight, measured by your ability to identify letters or numbers on a standardised eye chart from a specific viewing distance.
Visual acuity, eyesight and vision: What's the difference? Visual acuity To answer these questions, let's take a closer look at how opticians measure the quality of your vision.
Is it possible to achieve even better than 20/20 vision? And what is "perfect vision" anyway? If you have an eye exam and are told you have 20/20 (or 6/6) vision, does this mean you have perfect eyesight?
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