An eyeglass prescription often appears to be a complex array of numbers and abbreviations. These forms are a precise code that eye care professionals use to communicate specific measurements about a patient’s vision and the necessary lens correction. Understanding these measurements is the first step toward knowing how your corrective lenses work. The term “DIST VA” is one of the specific data points that helps define the current state of your sight.
What DIST VA Stands For and Where to Find It
DIST VA stands for Distance Visual Acuity, which measures the sharpness or clarity of a person’s vision when looking at distant objects. This metric quantifies how well the eye can distinguish shapes and fine details, such as reading a road sign or recognizing a face across a room. The result is diagnostic information representing the eye’s current ability to focus light and process the image on the retina.
This measurement is determined during the eye exam using an eye chart and is usually recorded separately from the main grid of lens powers. On a prescription form, it may appear in a column or box labeled “VA” (Visual Acuity) or “DVA” (Distance Visual Acuity). The score recorded reflects either the patient’s uncorrected vision or their “best corrected” visual acuity achieved while wearing their current corrective lenses.
Interpreting Visual Acuity Scores
Distance Visual Acuity is expressed as a fraction derived from the standard Snellen eye chart test. This common eye chart, featuring rows of letters that decrease in size, is the primary tool for measuring distance vision clarity. The fraction, such as 20/40 or 20/20, compares the patient’s visual performance to that of an average person.
The first number in the fraction, usually 20 in the United States, represents the distance in feet the patient stands from the chart during the test. The second number indicates the distance in feet at which a person with “normal” vision could clearly read the same line of letters. A score of 20/20 is the standard for normal visual acuity, meaning the patient sees at 20 feet what the average person sees at 20 feet.
A score with a larger second number, such as 20/40, indicates the patient’s vision is less sharp than the standard. A person with 20/40 vision must be 20 feet away to see a letter that an average person could clearly read from 40 feet away. Conversely, a score like 20/15 suggests better-than-average vision; this person sees clearly at 20 feet what the average person would need to see at 15 feet.
While the 20-foot standard is common in the U.S., many countries use a metric equivalent where the testing distance is six meters. In this system, 6/6 vision is the equivalent of 20/20, and 6/12 is comparable to 20/40 visual acuity. The core principle remains the same: the fraction provides a functional measure of how far the patient’s vision deviates from the established norm for clarity.
Distinguishing Acuity from Corrective Lens Power
Distance Visual Acuity is a measurement of current ability, whereas the bulk of the prescription is a set of instructions for correction. The SPH (Sphere), CYL (Cylinder), and Axis values found on the prescription are the precise lens powers, measured in diopters, that are needed to correct the refractive error. DIST VA is the result of the eye exam, while SPH/CYL are the solution prescribed by the doctor.
The spherical power (SPH) indicates the main strength of the lens needed to correct nearsightedness or farsightedness. The cylindrical power (CYL) and Axis values account for astigmatism, which is the irregular curvature of the cornea or lens that distorts vision. These prescriptive values instruct the laboratory how to shape the lens to ensure light focuses correctly on the retina, ultimately improving the visual acuity score.
Visual acuity only measures the sharpness of vision, but it does not account for other factors of sight like color vision, depth perception, or the ability of the eyes to work together. A complete eye examination includes testing for best corrected visual acuity, which determines the highest clarity achievable with the optimal lens power. The doctor uses the DIST VA score as a baseline to determine the strength of the SPH and CYL needed to improve the patient’s vision to the best possible level.
Distance Visual Acuity is conceptually distinct from Near Visual Acuity, often abbreviated as NV or NVA on a prescription. Near VA measures vision clarity at a reading distance. A reduced score here indicates the need for an additional corrective power, listed as the ADD (Addition) value. This ADD value is necessary for reading glasses or the lower portion of a multifocal lens.