Having trouble seeing at night or in dim light? Here’s what it could mean

If it seems when you’re driving at night that you struggle to see — no matter how much cleaner you spray on the windshield — the problem may not be on the glass.

Everyone has more trouble seeing at night or under dim lights, but that struggle also could indicate that you need to update your glasses prescription, or that you have another condition. Difficulty seeing at night can be a symptom of a number of common vision problems including cataracts, dry eye and diabetes.

Cataracts

As we get older, there’s no way to avoid developing cataracts. The lenses in your eyes get cloudy over time, so less light gets through. That makes objects appear blurry, and some of the light scatters, which increases the glare you experience from oncoming car headlights, for example.

One of the first symptoms of cataracts is glare. Cataracts grow slowly as proteins within the eye lenses deteriorate. While the breakdown of proteins in the lens of an eye starts around age 40, cataract symptoms usually don’t happen until you’re in your 60s.

Most people need cataract surgery when they’re in their 70s. However, trauma to your eyes can cause cataracts to form as early as in your 20s. Whatever age you experience the effects of cataracts, they can be cured with surgery that removes the cataracts.

Dry eye

Straining to see in darkness or dim light also could indicate you have dry eye, a disease in which the quality or amount of your tears isn’t enough to keep your eyes lubricated. That can lead to damage to the surface of your eye.

Dry eye can happen at any age but is more common in people who are middle-aged or older. Along with having trouble seeing a night, someone with dry eye can experience off and on blurriness as well as itchy, stinging eyes. Dry eye can be treated with artificial tears. Some people also take fish oil.

Diabetes

Poor vision at night is one of the more common visual complications that comes with diabetes. Other symptoms include floaters and blurred vision. Blood and oxygen flow to the eyes is high, so if you’re diabetic and your blood sugar is erratic, that will affect oxygen levels in your eyes and your ability to see well. I have some patients who discovered from an eye test that they have diabetes. Even if you have diabetes, keeping your blood sugar levels under control will maintain your vision.

Diet matters to eyesight

In general, what’s good for your body is good for your eyes, so eating a varied diet with a lot of colorful fruits and vegetables is important. The longtime notion that carrots are good for your eyes is somewhat true — carrots and other orange-colored vegetables are high in beta-carotene, a form of vitamin A, which is essential for seeing well. Green leafy vegetables contain lutein and zeaxanthin, which are carotenoids, the antioxidants that come from the yellow, orange or red pigment in fruits and vegetables, and are important for the retina, the layer of cells lining the back wall inside the eye. Healthy fats, such as fish and nuts, contain omega-3s, which are fatty acids that some doctors believe are good for the tear film and for preventing dry eye.

Test your vision frequently

If you struggle with your vision, it’s best to get your eyes tested every one to two years. Sometimes vision loss happens slowly. Optometrists can see losses and help improve your vision. Through testing, we can also see signs of diabetes, high blood pressure and high cholesterol.

Screen users should take breaks

When you spend a lot of time looking at a screen, remember the 20-20-20 rule to help maintain your eyesight: Every 20 minutes, look away at an object that’s about 20 feet away for 20 seconds or more. Look out a window or get up and walk your dog. Your eyes can get locked in to focusing up closely, and if you do it too long, things can seem blurry when you look farther away. The 20-20-20 rule can help keep your eyes from straining.