Do you have problems seeing at night? Millions of Americans do. You may just need glasses, especially if you’re nearsighted. On the other hand, it could mean that you have cataracts or other issues. If you’re afraid to hit the road after dark because you can’t see, let your doctor know.
What Causes It?
A wide range of conditions — from sun exposure to diabetes — makes it hard to see at night:
Cataracts . Your eye’s lens is right behind the pupil. As you age, cells grow and die inside it. That builds up debris and leads to cataracts. They don’t hurt, but they do get worse and slowly cloud your lens. The first symptom is often worse night vision. Because cataracts distort the light that comes into your eyes, you may see halos around lights — again, mostly at night. Blurry vision is also common.
Lack of vitamin A. It’s found in carrots and leafy vegetables. It helps keep the retina — the back of your eye where images are focused — healthy. Most Americans get enough vitamin A in their diets, but if you have a health issue that makes it hard for you to absorb nutrients (Crohn’s disease, celiac disease, gastric bypass), you might have night vision problems.
Not enough zinc. Without it, vitamin A may not work as well as it should. The result: night blindness. Beef, poultry, beans, and nuts are rich sources. Most people in the U.S. get plenty of it from their food.
Retinitis pigmentosa. This rare genetic disorder affects young people, usually before age 30. A decline in night vision is often the earliest symptom. Some people lose all their sight. Others keep some vision.
Sunlight exposure. If you think your night vision is worse after a trip to the beach, you’re probably right. Sustained bright sunlight can worsen night vision for up to two days. Always wear your sunglasses to avoid this.
Diabetes . It makes you more likely to have night vision problems. Over years, high blood sugar damages the blood vessels and nerves in your eyes, which leads to a condition called retinopathy. If you have trouble seeing in low light, either indoors or outside, talk to your doctor.
How Is It Diagnosed?
A simple exam and conversation at an eye doctor’s office can show the cause of your night blindness. The doctor will use drops to open your eyes up wide (he’ll call this dilation). Then he’ll look into them with a slit-lamp, an upright microscope with a bright light on it.
How Is It Treated?
What you can do for night blindness depends on the cause.
Cataracts are removed surgically. The doctor will replace your clouded natural lens with a clear artificial model known as an intraocular lens. Most people have much better vision afterward, but some still need glasses.
Diabetic retinopathy is easy to prevent if you keep tight control of blood sugar levels with medicines and diet. One treatment uses a laser to destroy the tiny blood vessels that threaten your vision. This process, called panretinal photocoagulation, will preserve your overall sight but could reduce your night vision.
Lack of vitamin A or zinc aren’t common causes of night blindness. But it won’t hurt to eat foods rich in these nutrients if you have trouble seeing at night.
WebMD Medical Reference Reviewed by Alan Kozarsky, MD