Each state has its own legal vision requirements for drivers, and those with glaucoma and other vision-related issues should carefully monitor their vision to determine whether or not it’s safe to stay on the roads. Amidst the rapid aging of the U.S. population, research has also shown that older adults with glaucoma may be at significantly higher risk for motor vehicle accidents than those without.* Learn what signs to look out for if you or someone you know has low, or worsening, vision.

What did the study entail?

The study, conducted at the Wills Eye Hospital in Philadelphia and presented at the 2019 Association for Research in Vision and Ophthalmology (ARVO) Conference, involved 161 participants (average age 64) with moderate glaucoma in at least one eye. 

Once a year for four years, the researchers tested the following of each participant:

• Visual acuity (how sharply they can see letters, shapes, or symbols at a given distance)
• Visual field/peripheral (side) vision
• Contrast sensitivity (discerning black, white, and shades of grey)
• Ability to perform mundane visual tasks (e.g., matching socks, reading street signs, etc.)

Each year the participants were also asked if they had been involved in any motor vehicle accidents (MVAs) as a driver during the previous year.

• Between 5% and 10% of the participants each year had.
• This rate contrasts sharply with the 1.1% rate of MVAs for Pennsylvania drivers of comparable age (61-65 years old) without glaucoma.

What was the legal visual driving range?

Despite having moderate glaucoma, all participants were within the visual range for driving legally in Pennsylvania. The legal vision requirement for driving is usually 20/40 for nighttime driving and 20/70 for daytime driving, but the requirements vary from state to state.

How did so many accidents occur?

The researchers found that impaired peripheral vision in either eye was an independent risk factor for MVAs, suggesting that, even though someone with early to moderate glaucoma can have 20/20 central vision, side vision impairment can cause blind spots that are particularly dangerous for drivers. 

Is glaucoma the only vision problem that affects driving?

Glaucoma is not the only vision issue that affects driving. Most people’s vision goes through stages as they age—often worsening, then stabilizing, then worsening again. 

The most common causes of reduced vision are:

• Cataracts
• Macular degeneration (more commonly in Caucasians) 
• Glaucoma (more commonly in Black and Hispanic populations) 

Cataracts can be fixed with surgery, but macular degeneration and glaucoma can only be managed or stabilized and further damage delayed.

When should people with low, or worsening, vision stop driving?

There’s no federal standard or hard-and-fast rule for when it’s time to stop driving. Too often, a person is forced to stop driving because a car accident resulted in their driver’s license being revoked. 

To avoid this situation, it’s important for drivers, family members, and healthcare providers—whether they be optometrists, ophthalmologists, or primary care physicians—to initiate conversations about driving risks as the driver’s vision declines.

Jonathan Myers, MD, Chief of the Wills Eye Hospital Glaucoma Service, and co-author of the study, insists that there’s no shame in giving up driving to ensure one’s safety and the safety of others. He acknowledges, however, that the road to willingly giving up one’s car keys can be bumpy, which is why it’s good to have an open dialogue and get everyone on board.

“Driving isn’t simply about driving,” Myers said. “It’s also about independence for an aging population, so these can be very difficult and emotional conversations. As doctors, we need to care for the whole patient and be part of the care team with the family.”

To learn more about legal vision requirements for drivers in your state, head to the Prevent Blindness website.

*Wills Eye Hospital. (2019, May 22). Wills Eye Hospital Research Suggests Glaucoma Patients May Be at Higher Risk of Motor Vehicle Accidents Than Those of Similar Age. Eyewire News. https://eyewire.news/articles/wills-eye-hospital-research-suggests-glaucoma-patients-may-be-at-higher-risk-of-motor-vehicle-accidents-than-those-of-similar-age/

Any sources from outside of Prevent Blindness do not imply an endorsement from Prevent Blindness. The contents of the material used are the responsibility of the authoring organization, Responsum Health.