Driving at night can be challenging, even under normal circumstances. There are the lights from oncoming traffic, the reduced ability to see important landmarks, and the risk of impaired drivers. However, although driving at night is harder, if your nighttime vision is especially bad—or if it has gotten worse in recent months—you should get it checked out by a doctor, as it can be an early warning sign of a more serious issue.
“When nighttime happens, our whole optical system changes a little bit,” said Sumitra Khandelwal, an ophthalmologist at Baylor College of Medicine. At night, our pupils dilate in order to take in additional light. As a result, our vision becomes more sensitive to a number of issues that may not be noticeable during the day.
Vision issues can be more noticeable at night
Some eye-related issues may be more pronounced at night. “If you have something like cataracts, which is an opacity to the natural lens, you may not notice challenges during the day, because the pupil is a nice, normal size,” Khandelwal said. “But at nighttime, when the pupils get big, you’ll really notice glare and streaking of light.”
This is also true for certain issues of the cornea or retina that can become much more noticeable at night. “The cornea is like the window to the eye,” Khandelwal said. “It needs to be nice and clear and crisp, without any opacities or areas of abnormality, in order to see your best.”
Poor nighttime vision can indicate you need a new prescription
As Khandelwal notes, poor nighttime vision can also be a sign that your eyeglass prescription needs to be checked and updated. “We all get a little more nearsighted at nighttime,” Khandelwal said. This is called night myopia. For some people, their night myopia is a little more pronounced, while for other people, it may be a sign that their prescription needs to be re-checked.
To check whether night myopia is an issue, doctors will dilate a person’s pupils and check their prescription for a large discrepancy. “We commonly see that when our pupils dilate, our prescription changes just a little bit,” Khandelwal said. “Some people are very sensitive to that.”
If your nighttime vision is bad, go see a doctor
If you have poor nighttime vision, or you’ve noticed a recent change in your nighttime vision, you should schedule an eye exam. “Sometimes people feel that decreased nighttime vision is just part of the aging process, but it’s really important to get it checked out,” Khandelwal said. “Most people have great night vision, even as they get older. There’s no reason for someone to change their lifestyle, such as by not driving at night, just because of their vision, when oftentimes there’s something that we can do to help.”
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