In medical terminology, VA most commonly stands for visual acuity, a measurement of how clearly you can see. You’ll find this abbreviation on eye exam records, hospital charts, and clinical notes. It can also refer to the Veterans Affairs healthcare system, the vertebral artery, a ventriculoatrial shunt, or valproic acid, depending on context. Visual acuity is by far the most frequent clinical use.
Visual Acuity: The Most Common Meaning
Visual acuity is a measure of how sharp and clear your eyesight is at a given distance. When a doctor writes “VA 20/20” in your chart, they’re recording that you can see at 20 feet what a person with normal vision can also see at 20 feet. This has been used clinically for hundreds of years as a standard way to gauge the clarity of a patient’s vision.
The familiar eye chart you read during an exam is called a Snellen chart. It uses rows of letters that get progressively smaller. The top number in your result is the distance you stood from the chart (usually 20 feet), and the bottom number is the distance at which someone with normal eyesight could still read the smallest line you were able to make out. So if your result is 20/40, that means you need to stand at 20 feet to see what someone with normal vision can see from 40 feet away.
A common misconception is that 20/20 means perfect vision. It doesn’t. It only measures clarity at a distance. It says nothing about peripheral vision, depth perception, color vision, or how well you see up close. You can have 20/20 visual acuity and still need reading glasses or have blind spots in your side vision.
What the Numbers Mean in Practice
Visual acuity scores fall along a spectrum. Here’s how the World Health Organization categorizes them:
- 20/40: Mild vision impairment. Many states set this as the minimum for driving without corrective lenses.
- 20/70: Moderate vision impairment. Reading standard print becomes difficult.
- 20/200: Severe vision impairment. This is the threshold for legal blindness in the United States. At this level, you’d need to stand 10 times closer to an object, or the object would need to be 10 times bigger, to see it as clearly as someone with normal sight.
- 20/400 or worse: Classified as blindness by international standards, though some usable vision may remain.
The legal blindness threshold of 20/200 applies even with your best correction, meaning glasses or contacts. If one eye sees better than the other, the measurement comes from the better eye.
VA as the Veterans Affairs Health System
Outside of clinical charts, VA frequently refers to the U.S. Department of Veterans Affairs, specifically its healthcare arm called the Veterans Health Administration (VHA). This is one of the largest integrated health systems in the country, and it operates differently from most hospitals: the VHA owns its facilities and directly employs its doctors and nurses rather than contracting with private providers.
Not every veteran qualifies for VA care. Eligibility falls into two tiers. The first tier includes veterans who are guaranteed care: those with service-connected disabilities, Medal of Honor or Purple Heart recipients, former prisoners of war, World War II veterans, veterans exposed to toxic substances like burn pits, and veterans whose income falls below a certain threshold set by a means test. The second tier covers veterans who may receive care if resources allow, but access isn’t guaranteed. If you see “VA” on a referral form or insurance document, it’s almost certainly referring to this system.
VA as the Vertebral Artery
In anatomy and neurology, VA can stand for vertebral artery. You have two of them, one on each side of your neck, and together they supply about 28% of your brain’s blood. They feed the brainstem, cerebellum, upper spinal cord, and the back of the brain.
Each vertebral artery starts near the collarbone, climbs upward through small openings in the neck vertebrae, passes behind the top vertebra (the atlas), and enters the skull through the large opening at the base called the foramen magnum. Once inside the skull, the two vertebral arteries merge into a single vessel called the basilar artery. Problems with these arteries, such as blockages or tears in the vessel wall, can cause dizziness, coordination problems, or stroke affecting the back of the brain.
VA Shunt in Neurosurgery
A VA shunt, or ventriculoatrial shunt, is a device used to treat hydrocephalus, a condition where excess fluid builds up in the brain’s internal chambers. The shunt consists of a thin tube placed inside one of those chambers, connected through a one-way valve to a second tube that runs under the skin down to the heart’s upper chamber (the atrium). Excess brain fluid drains through the system and gets absorbed into the bloodstream.
Most people with hydrocephalus get a ventriculoperitoneal (VP) shunt instead, which drains fluid into the abdominal cavity. The VA shunt is reserved for cases where the abdomen isn’t a viable option, perhaps because of prior surgery, infection, or scarring. Studies suggest the VA shunt is roughly as safe as the VP version for certain types of hydrocephalus.
Valproic Acid in Pharmacology
In medication contexts, VA (or more commonly VPA) can refer to valproic acid, a drug used primarily to control seizures. It’s approved for treating several types of epilepsy in adults and children aged 10 and older, including complex partial seizures and absence seizures. Doctors also prescribe it off-label for bipolar disorder, migraine prevention, nerve pain, and agitation.
How to Tell Which VA Is Meant
Context almost always makes the meaning clear. If you’re reading an eye exam report or ophthalmology notes, VA means visual acuity. If a neurosurgeon mentions a VA shunt, they’re talking about draining brain fluid. In a neurology or radiology report about your neck or brain, VA likely refers to the vertebral artery. On insurance paperwork or military health documents, it means the Veterans Affairs system. When in doubt, the surrounding words will point you to the right definition.