Many of us assume that our eyesight should grow worse as we age. While it’s true that your vision tends to change after age 40 and you may need reading glasses, for example, “vision loss is not an inevitable part of aging,” says Anne Sumers, M.D., a clinical spokesperson for the American Academy of Ophthalmology
. Something like loss of peripheral vision, or tunnel vision, could be a sign of glaucoma, a condition that affects three million Americans. Half of those with glaucoma don’t know they have it, Dr. Sumers says, because many people experience few or no early warning signs. Glaucoma causes damage to the optic nerve and is usually associated with high pressure inside the eye. Although “anyone who has blurry vision should be evaluated,” says Lisa Park, M.D
., associate professor of Ophthalmology at Columbia University Medical Center in New York City, tunnel vision or a sudden loss of vision in one eye could signal a blood flow issue and should be investigated immediately.