Maybe you’ve noticed it’s slowly becoming harder to see at night. Or maybe the change is more sudden. You get into your car one night and the road in front of you looks blurry. Either way, it can be confusing and frustrating to lose your ability to see objects clearly in the dark or in low light.

Figuring out the root cause of your night vision loss is the first step toward seeing better when the sun goes down, according to Raul Ramos, O.D., an optometrist working in an America’s Best Contacts & Eyeglasses in Coral Gables, Florida. Here are the most common reasons you might be losing your night vision.

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1. Night Myopia

Myopia makes it harder to see objects that are farther away. Even if you have 20/20 vision during the day, which means you don’t need eyeglasses or contact lenses, you can still have trouble seeing when there’s less light. Dr. Ramos says this is more common in women, particularly young women.

Night myopia can impair your ability to drive because it causes temporary nearsightedness. That means objects in the distance, like street signs, become harder to see.

The cause of night myopia is unknown, Dr. Ramos says. But it likely has to do with how the pupil adjusts to light changes. Often, those with night myopia see perfectly fine during the day, so treatment usually consists of wearing corrective glasses at night.

2. Aging

The eyes have two types of photoreceptors, called rods and cones, that transmit electrical impulses to the brain based on how light is perceived, says Dr. Ramos.

• The rods are responsible for allowing you to see at night.
• The cones are for daytime and color.

“As we age, there’s a natural loss of the rods, which makes it harder to see at night,” Dr. Ramos says. "It also makes adapting to low light more difficult.”

If you’re outside during a sunny day and come inside, it takes a few minutes for your eyes to adjust, and you’ll see a “darker” room because of it. As you get older, it can take much longer for your eyes to adjust, he says.

Your eye doctor can recommend lenses that can help with this adjustment by minimizing glare. The National Traffic Safety Administration recommends that older adults who have trouble seeing well at night restrict their driving to daytime hours only.

3. Cataracts

Another issue that may come up, especially for older people, is cataracts. This is when the lens inside the eye becomes cloudy. Cataracts usually happen gradually over the course of years. One major symptom is blurriness, but most people notice reduced night vision as a first sign, Dr. Ramos says.

Cataracts can be monitored and there are steps your eye doctor can recommend that may help slow the progression. But there’s only one treatment for the condition, which is cataract surgery.

It’s usually done when someone has had cataracts for some time and it’s gotten to the point where daily routines are being interrupted. Surgery is also considered when driving in the evening becomes difficult or impossible.

This is one reason regular eye exams are so important, even if you have no vision complaints. Your eye doctor can spot the early signs of cataracts and recommend steps to slow the progression. This might include a new prescription and regular use of sunglasses. Once cataracts are detected, your doctor can monitor the progression, help you manage symptoms, and provide guidance on when surgery may be needed.

4. Diabetes

Any type of disease that affects your retina can impact your ability to see in low light, Dr. Ramos says, and this includes diabetes. Diabetes can damage your blood vessels and nerves. If this affects the eyes, it can cause a condition called diabetic retinopathy.

According to the National Eye Institute, diabetic retinopathy may lead to vision loss and even blindness. People with diabetes should get an eye exam at least once a year.

If you have diabetes, learn how to protect your vision and prevent eye-related complications.

5. Glaucoma

Glaucoma is a disease that damages your eye’s optic nerve. It tends to worsen over time, especially when it comes to your peripheral vision.

“With glaucoma, you tend to be left with central vision,” Dr. Ramos says. “If you lose that peripheral vision ability, seeing at night will be much more difficult.”

Usually, the progression is so gradual you may not notice right away that it’s happening. But Dr. Ramos says one sign is that it’s becoming increasingly challenging for you to see while driving at night, especially signs and landmarks that are not directly ahead of you.

6. Eye Drops for Presbyopia

Age-related vision issues tend to start in your late 40s, particularly difficulty with seeing objects up close, says Griffin Durias, O.D., an optometrist working at an America’s Best Contacts & Eyeglasses in Machesney Park, Illinois. This is called presbyopia, and it’s often addressed with corrective measures like reading glasses, bifocals, or certain contact lenses.

Another option is a brand of prescription eye drops called VUITY, he says, which are specifically designed to address presbyopia.

While these work for some people, one of the cautions is that it’s not recommended when driving at night or performing hazardous activities in poor lighting. That’s because it works by constricting your pupils, Dr. Durias says.

When you’re trying to see in low light or in the dark, your pupils naturally dilate to let in more light so your vision adjusts. But if they stay constricted, as is the case with VUITY, it makes it difficult for the eyes to transition to a darker field of vision.

Why Regular Eye Exams Are Important

Whether you think your issues with night vision are a problem or just another sign of aging, Dr. Ramos points out that it’s important to have a routine eye exam every year. The underlying causes, he says, are most likely correctable.

Plus, he reminds, it’s a good opportunity to check the overall health of your eyes and learn helpful tips to protect your vision for years to come.