You haven’t gone out to play in a long time Several studies have linked spending time indoors to nearsightedness—especially among young children. But getting outside may prevent this vision problem. Why? Sunlight causes your pupils to shrink, which reduces visual blur, suggest a study from the University of Sydney in Australia. The study authors say sunlight may also strengthen the eye through the release of the neurotransmitter dopamine, which spikes when you’re retinas are exposed to natural light. You’re not a fan of berries If you’re having trouble seeing at night, oxidative stress may be partly to blame, suggests research from the University of Massachusetts Medical School. Several studies have linked eating berries—especially bilberries, a European relative of the blueberry—to improved night vision. The antioxidants in bilberries (and blueberries) may help limit the oxidative damage your eyes put up with as you age, shows research in Molecular Nutrition and Food Research. You’re low on Dage-related macular degeneration Women who get plenty of vitamin D are roughly 44% less likely to develop (AMD), shows research from the University of Buffalo. AMD is the leading cause of vision loss among people older than 50, according to the National Eye Institute. But vitamin D—whether from fish, sunlight, or D-fortified foods like milk—may battle the type of inflammation that contributes to AMD, the study authors say. MORE: The 10 Worst Things That Can Happen When You Don’t Get Enough Vitamin D You went to grad school Although the research is controversial, a pile of studies has found a link between lots of reading—a.k.a., “near work”—and nearsightedness. Your eyes work harder to focus on things that are close (as opposed to far away). So some of these studies’ authors have theorized that burying your face in books, especially during childhood, can cause myopia. Higher education—and all the textbook reading that comes with it—has also been associated with higher rates of nearsightedness, shows a study from the Ophthalmic & Physiological Optics. (It’s possible a lack of sunlight—and not all that time reading—may actually be to blame, the study authors say.) MORE: 5 Ways to Age-Proof Your Vision Your smartphone is basically attached to your hand Hours of exposure to the harsh “blue light” your laptop, tablet, and phone screens spit out could lead to “computer vision syndrome”—a catchall term for eye-related health problems ranging from blurred vision to headaches and nausea. If your eyes feel sore or strained after spending time on your devices, follow the 20-20-20 rule: Every 20 minutes, stare at something 20 feet away for 20 seconds. You’re on acne medication As if worrying about your complexion weren’t enough, one type of potent, prescription-only acne medication may cause blurriness or night-vision problems, shows a study from Lens and Eye Toxicity Research. Isotretinoin, the generic name for the drug, may increase the amount of UV light your eyes absorb, which could explain the damage, the study author says. You’re knocked upJournal of Pregnancy Suddenly struggling to make out road signs and billboards? It’s somewhat common for pregnant women to suffer a drop-off in their distance vision, shows research from the . While the study authors can’t say what causes these vision problems, they offer some good news: Your eyesight should return to normal after you’ve delivered your bundle of joy. You have diabetes Diabetes is one of the most common causes of something called “macular edema”—a form of blurred vision. In fact, blurry vision may be one of the earliest signs you’re developing type 2 diabetes. The disease cuts off blood flow to parts of the retina, and can eventually lead to blindness, shows research from Indiana University. MORE: 10 Things Your Eyes Say About You