A: There are lots of possibilities; your eye doctor can help with some of them. If your prescription has changed, you’re likely to notice it more at night. During the day, you have more visual cues, so you just fill in what you can’t quite see. That’s harder in the dark. Your ophthalmologist can also check for medical conditions. A common concern for aging eyes is cataracts, which affect the lens, at the front of the eye. Normally, the lens is clear, but when a cataract forms, the lens becomes more opaque. That can make it harder to see, especially at night, because it creates glare, fuzziness, and a “halo” effect around lights. Surgical treatments are available for cataracts. Diabetes can also cause vision problems, because higher blood sugar can affect the vitreous humor (the liquid in the middle of the eye) and cause temporary swelling inside the eye. (It’s true; read Is THIS Why You Can’t See?) There’s also a more obscure possibility that your doc will want to rule out: retinitis pigmentosa, a rare, inherited condition affecting the retina, or back of the eye. The retinal cells responsible for night vision are rod shaped; the ones for day vision are cones. RP affects rods more than cones, so night vision suffers first. If none of those medical reasons are to blame, there are other possibilities. Does your night vision get better after 15 or 20 minutes? Being in bright, unfiltered light for 2 to 3 hours can slow how quickly your eyes adapt to lower light: Intense light amplifies your cone cells but doesn’t activate your rods, so it takes the rods longer to come back online in dim light, especially as you age. Allowing 20 minutes for your eyes to adapt before you hit the road can help, as can wearing sunglasses during the day. And try a multivitamin that covers your vitamin A and C and beta-carotene needs, as well as omega-3 capsules. SANJAY GUPTA, MD, is chief medical correspondent for CNN and a practicing neurosurgeon at Emory Clinic in Atlanta. Send your questions to askdrgupta@prevention.com. Sanjay Gupta, MD, is chief medical correspondent for CNN and a practicing neurosurgeon at Emory Clinic in Atlanta.
