How old would you say is “old?” I wouldn’t consider a 40-year-old to be especially old. It’s by definition “middle-aged.” But in Maryland, that’s the age cutoff at which drivers must pass a vision test every time they renew their license. This makes Maryland a unique case.

In the United States, the process of getting and maintaining a license is different in every state. Many states require drivers to pass a vision test whenever renewing their license—at any age. Other states never require a vision test. But a handful of states add the requirement later, for older drivers.

Vision-test age cutoffs for older drivers in the U.S.

Alaska: 69, Arizona: 65, California: 70, Florida: 80, Illinois: 75, Indiana: 75, Iowa: 70, Louisiana: 70, Maine: 62, Maryland: 40, Massachusetts: 75, Nebraska: 72, Nevada: 71, New Mexico: 75, Ohio: 65, Oregon: 50, South Dakota: 65, Texas: 79, Utah: 65, Virginia: 75.

This information is courtesy of Progressive Insurance. It’s unclear which states allow you to continue driving with a “corrective lenses” stipulation on your license after you fail the vision test.

Those aren’t the only states with stricter renewal guidelines for older drivers. Many more states require older drivers to renew their license more often than younger drivers.

Maryland’s an interesting case. Of the states with an age-based vision test requirement, it has the lowest age limit. That said, Maryland residents only have to renew their license every eight years—no matter their age. So if a Maryland driver renews their license when they’re 39, they won’t have to pass a vision test until they’re 47. That’s nearly as old as Oregon’s 50-year-old cutoff.

The United Kingdom made headlines recently when it introduced compulsory eye tests that all drivers over 70 must take every three years. It implemented this ruling nationwide. Fourteen European countries have some kind of test for older drivers—ranging from a medical or vision test to retaking a skills-based test.