What are visual acuity tests used for?
Visual acuity measurement is a good screening tool because normal visual acuity requires that all levels of the visual system function properly. The optical system of the eye must project a sharp image of the outside world onto the retina. The retina must then be able to translate this image into neural impulses. Finally, the neural impulses must travel to the brain, where they are analyzed and recognized. Therefore, a wide array of different visual disorders (but not all) can affect visual acuity. Because visual acuity is so easily measured, it is often used as a primary eligibility criterion, such as 20/20 for a pilot’s license, 20/40 for a driver’s license, 20/200 for certain disability benefits. However, the ability to perform various tasks depends on many more factors than visual acuity alone. For those disorders that affect visual acuity, it also is a good follow-up tool to document whether a condition is worsening or recovering or to record the effect of various interventions. F
