This could be the reason why seeing at night may be difficult
Certain eye conditions may make it challenging to see in the dark. Find out which ones and what to do.
Over time, many people may experience low vision, which is a vision problem that makes everyday activities hard to do. Low vision may be more common in older adults because they may have many of the eye conditions that may trigger it, according to the National Eye Institute.1
One type of low vision is night blindness, also called nyctalopia. This is a decreased ability to see things at night and in dimly lit settings. Having night blindness may make it difficult to drive and get around in rooms with poor lighting.2
Learn what may affect the ability to see at night, plus 5 reasons why it may be happening.
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What happens to the eyes in the dark
Light travels from the pupil, at the front of the eye, toward the back of the eye. Eventually it gets to the retina, the layer of tissue near the back of the eye. The retina sends electric signals through the optic nerve to the brain. The brain then translates the signals into the images people see.3
The retina contains 2 types of light-detecting cells, called rods and cones. Rods are there to manage vision in dim light while the cones handle color vision and help with seeing in fine detail.2
During the day, the cones are in use. But when it’s dark, most of the rods are activated, while only a few cones are working. That’s why at night, vision is mostly or all in black and white.4
Older adults may notice that it takes longer for their eyes to focus and adjust in the dark. That’s because rod and cone density decreases as people get older, says Juanita Collier, O.D. She’s an optometrist and founder of 4D Vision Gym, a private optometric vision therapy practice in Cromwell, Connecticut. “As rod cell density decreases, picking up moving objects at night might become more difficult.”
The iris (the colorful part of the eye) and pupils also play a part. To let in light, the muscle in the iris helps the pupil get smaller or larger, depending on how much light is coming in. If the iris doesn’t work well, the pupils may not get big enough at night to let more light in.2
5 reasons why people might experience night blindness
Night blindness isn’t an eye disease in itself. Instead, it’s a symptom of another eye condition or something else, such as a lack of certain vitamins.2 Here are 5 possible causes of it being harder for people to see at night or when the lights are low.
1. Cataracts
Cataracts are a clouding of the eye’s lens. Cataracts may cause blurred and hazy vision, make eyes more sensitive to glare, and lower the ability to see colors. If left untreated, cataracts may eventually lead to vision loss. In fact, cataracts are the leading cause of vision loss in the United States.5
Cataracts may block the way light travels through the eye. The light scatters and things have a glare and a halo around them, says Dr. Collier. “It’s hard to see through the scattered light. At night, it can be more blinding, especially when driving,” she explains. “People 65 and older aren’t driving as much at night, and a lot of the time that has more to do with having cataracts.”
2. Dry eye
Many people have dry eyes. That’s when a person produces too few and poor-quality tears. Tears play an important role in keeping the surface of the eye healthy. They also help a person see clearly.6
Aging may dry up tear production, as may certain medications, such as allergy and blood pressure medications, and LASIK surgery.
One symptom a person with dry eye may experience is being more sensitive to light.6 “A person with severe dry eye can experience something similar to cataracts,” says Dr. Collier.
If the tear film — the thin layer of liquid coating the eye’s surface — breaks up or evaporates too quickly, it can affect the way light travels through the eye, Dr. Collier explains. “The light will scatter and make it difficult to see at night,” she adds.
3. Age-related macular degeneration
In individuals with age-related macular degeneration, the buildup of waste products in the macula may decrease the ability of cones to function, says Dr. Collier.
“Macular degeneration can lead to a loss of central vision, which is whatever you’re looking at in front of you,” says Dr. Collier. “Central vision is crucial when driving, reading and seeing details clearly.”
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4. Glaucoma
Glaucoma is a group of eye diseases that damage the optic nerve. Typically, it’s caused by a buildup of fluid and pressure in the eye, but not always.5
People with glaucoma slowly lose vision, first the side (peripheral) vision, then the central vision. The symptoms may include blurry or wavy vision, day or night. Left untreated, it may cause blindness.5
Some of the medications used to treat glaucoma may make the pupils get smaller so more fluid drains out of the eye. That may lower eye pressure. But it may also make it harder for people to see at night or in dim light.7
5. Vitamin A deficiency
Vitamin A may be important for eyesight and the way the eye sees in the dark. Vitamin A helps the eye produce certain pigments in the rods that help it detect low light. Too little vitamin A may lower the production of the pigments. The result may be night blindness.8
Vitamin A also nourishes the rest of the eye, including the cornea. And it helps the eyes make tears to keep them hydrated — and keep light traveling through them properly.
Eating a healthy diet, rich in foods with vitamin A, may help keep night vision issues at bay. Find vitamin A in all sorts of foods, including leafy greens as well as orange and yellow produce, milk and eggs.9
What to do about night blindness
If seeing at night has become a problem, people may want to discuss it with their eye care provider at their next eye exam. Night blindness may be treatable, depending on the cause. “It may even be as simple as having an antireflective coating on your distance glasses,” says Dr. Collier.
An eye care provider might suggest other strategies too, such as placing brighter lights around the home, or eating more fruits and vegetables.
But it’s important for people to speak up. Even more important, keep up with regular eye exams — which may also help people be more comfortable discussing things with their eye care provider.
Providers in the UnitedHealthcare Vision Network are here to help keep your vision healthy. Search for an eye care provider now.
Sources:
- Low vision National Eye Institute, last updated November 2023.
- Night blindness (nyctalopia) Cleveland Clinic, last reviewed December 2023.
- How the eyes work National Eye Institute, last updated April 2022.
- Night vision Cleveland Clinic, last reviewed October 2022.
- Common eye disorders and diseases Centers for Disease Control and Prevention, last reviewed August 2023.
- Dry eye American Optometric Association.
- Glaucoma eye drops American Academy of Ophthalmology, February 2024.
- What is vitamin A deficiency? American Academy of Ophthalmology, May 2023.
- Vitamin A Harvard T.H. Chan School of Public Health, last reviewed March 2023.
