Most states require a visual acuity of 20/40 or better to get an unrestricted driver’s license. That means you need to see at 20 feet what a person with normal vision sees at 40 feet. If your vision falls below that threshold, you may still qualify for a license with restrictions, and corrective lenses (glasses or contacts) count toward meeting the standard.
Visual Acuity Standards for a Regular License
The 20/40 benchmark is the most common cutoff across the United States for an unrestricted passenger vehicle license. If you can hit 20/40 with both eyes open, whether naturally or with glasses, you’ll pass the screening without any driving restrictions placed on your license.
If your corrected vision falls between 20/40 and 20/70, many states will still issue a license but restrict you to daytime driving only. Below 20/70 with both eyes, most states will deny a standard license entirely. These thresholds vary slightly by state, so checking your own state’s DMV requirements is worth the effort if you’re close to a borderline.
When you wear glasses or contacts to pass the screening, your license gets a “corrective lenses” restriction. Driving without them after that is a citable offense, even if you feel like you can see fine.
What the DMV Vision Test Looks Like
The screening itself is quick and low-tech. You’ll look into a small machine (called a vision screener or optec) and read rows of letters or numbers, similar to the chart in an eye doctor’s office. The examiner tests each eye individually, then both together, with and without your glasses if you wear them. Some states also check that you can identify the colors of traffic signals: red, green, and amber.
If you fail the screening at the DMV, you aren’t permanently out of luck. Most states let you visit an eye specialist, get a current prescription, and return with documentation showing your corrected acuity meets the minimum standard.
Requirements for One-Eye (Monocular) Drivers
If you have functional vision in only one eye, you can still get a license, but the acuity bar is slightly higher. Ohio’s standards are representative: monocular drivers need 20/30 or better for an unrestricted license, compared to 20/40 for someone using both eyes. Between 20/30 and 20/60, a daytime-only restriction applies. Worse than 20/60, and the license is denied.
The tighter standard exists because driving with one eye eliminates stereoscopic depth perception and reduces your total field of view. Most monocular drivers compensate effectively over time, but the DMV screening accounts for the narrower margin of safety.
Peripheral Vision and Field of View
Sharp central vision isn’t the only thing that matters. For commercial vehicle drivers, federal regulations set by the FMCSA require at least 70 degrees of horizontal field of vision in each eye. Many states apply similar peripheral vision requirements to regular licenses as well, though the specific numbers vary.
Peripheral vision is what lets you detect cars merging from the side, pedestrians stepping off a curb, or a cyclist approaching an intersection. Conditions like glaucoma gradually erode peripheral vision, sometimes without obvious symptoms, which is why it’s tested separately from the letter chart.
Commercial Driver Standards
Commercial driver’s license (CDL) holders face the same 20/40 acuity threshold for both eyes, but the consequences of borderline vision are more restrictive. Drivers who meet 20/40 but fall under federal motor carrier regulations may be limited to intrastate operation only. Those between 20/40 and 20/70 get stacked restrictions: daytime driving in any vehicle plus intrastate-only for commercial vehicles.
Federal standards also require that commercial drivers demonstrate a field of vision of at least 70 degrees horizontally in each eye. Monocular commercial drivers face additional scrutiny and may need a federal vision exemption to operate interstate.
Color Blindness Usually Isn’t a Problem
No specific color vision test is required for a driver’s license. Federal regulations only ask that drivers can respond safely to colored traffic signals and devices. Since traffic lights are arranged in a fixed order (red on top, green on bottom) and most color-deficient drivers learn to distinguish signals by position and brightness, the vast majority of people with red-green color blindness drive without any restriction. Repeated studies of red-green color-deficient drivers have found no worse safety record compared to drivers with normal color vision.
How Eye Diseases Affect Your License
Cataracts, glaucoma, and macular degeneration are the three most common conditions that put a license at risk over time. None of them automatically disqualify you. With treatment, many people continue driving well into the advanced stages of these diseases. The key factor is whether your corrected acuity and field of vision still meet your state’s minimums at each renewal.
People with cataracts often notice glare and difficulty in low light before their acuity on a letter chart drops significantly. Cataract surgery frequently restores driving ability, and research shows the improvement in contrast sensitivity after surgery is actually the best predictor of better driving performance. Drivers with glaucoma tend to restrict night driving on their own as peripheral vision narrows. Those with macular degeneration, which attacks central vision, often avoid unfamiliar routes and longer distances first, then eventually stop driving when they can no longer pass the eye screening.
Self-regulation is common among older drivers with declining vision. Many voluntarily limit where and when they drive, sticking to familiar daytime routes, well before their license is formally restricted or revoked.
Contrast Sensitivity: The Gap in Screening
Standard DMV tests check how well you read high-contrast black letters on a white background. They don’t measure contrast sensitivity, which is your ability to distinguish objects from similarly colored backgrounds, like a gray-clothed pedestrian against a gray road on an overcast day.
This is a meaningful gap. Research has found that drivers with a history of crashes are six times more likely to have reduced contrast sensitivity than crash-free drivers. In driving simulator studies, reducing visual acuity alone to around 20/40 or even 20/80 had surprisingly little effect on how quickly drivers spotted pedestrian hazards. But when reduced contrast sensitivity was added on top of the acuity loss, reaction times increased significantly and drivers needed harder braking to avoid collisions. Contrast sensitivity predicted hazard detection performance better than acuity alone.
Despite this evidence, no state currently tests contrast sensitivity during license screening. Conditions like early cataracts can impair contrast sensitivity while your letter-chart acuity remains at 20/40, meaning you’d pass the DMV test but still have meaningfully reduced ability to spot hazards in real-world conditions. If you have an eye disease and notice trouble seeing in rain, fog, or dusk, that’s worth bringing up with your eye doctor even if your acuity numbers still look fine.
Bioptic Telescopic Lenses
If your best corrected vision falls between 20/100 and 20/200, you wouldn’t normally qualify for any license. But many states now allow bioptic telescopic lenses, which are small telescopes mounted in the upper portion of eyeglass lenses, to meet driving vision requirements. You drive using your regular prescription in the main lens and briefly glance through the telescope to read signs or identify distant objects.
States that permit bioptic driving typically require that the telescope bring your acuity to at least 20/40, and preferably no worse than 20/70. A restricted license with conditions like daytime-only or limited roads is standard. Not every state allows bioptic driving, and those that do usually require a specialized behind-the-wheel evaluation.