9 things your vision reveals about your health

When a healthcare provider (HCP) peers into your eyes, what are they looking for? All kinds of things, as it happens. 

"You can learn so much from the eyes. It's mind-blowing!" says integrative medicine specialist Robin Miller, MD. In addition to eye conditions, such as cataracts, HCPs can spot symptoms of other medical issues, including hypertension (high blood pressure), high cholesterol, diabetes, and even certain cancers. 

With that in mind, here are nine ways changes in your vision can hold important clues to your health.

Blurred vision may be a symptom of undiagnosed or poorly controlled high blood pressure, says Anne Sumers, MD, an ophthalmologist in Ridgewood, New Jersey. And in pregnant people, blurred vision could be a sign of preeclampsia, a condition that causes high blood pressure during pregnancy and may require bed rest for your safety and that of the developing fetus. An HCP may also spot swelling of the optic nerve when they peer into your retina. Blood vessels in the retina that look stiff, kinked, or silvery or coppery rather than red can be signs of high blood pressure.

When gazing into a patient's eyes, "I'm looking for signs of high cholesterol," says Dr. Miller. Yellow, fatty patches around your eyes are cholesterol deposits called xanthelasma, and they may indicate an elevated risk for heart disease. "That's pretty common to see in people with familial high cholesterol," she adds. 

Miller also looks for a white ring around the pupils, called a corneal arcus, which could either be a normal effect of aging or a sign you have high cholesterol. "It's actually a fat deposit," she says. If an HCP spots a xanthelasma or corneal arcus, it's a good idea to have your cholesterol checked.

Diabetic retinopathy is a well-known, leading cause of blindness, but high blood sugar can wreak havoc on your vision in other ways, too.

Blurred vision? Your contacts suddenly don't do the job? That can be a sign of undiagnosed diabetes, or, if you've been diagnosed with diabetes, poorly controlled blood sugar, says Dr. Sumers. And it's especially important to see your HCP if you're pregnant and experience changes in your eyesight, she adds. "Frequently, the first symptom of gestational diabetes is blurred vision."

A stroke or, to a lesser degree, transient ischemic attack (TIA), has plenty of scary symptoms—sudden weakness or numbness on one side of the body, difficulty speaking, and drooping on one side of the face, to name a few. But double vision or temporary loss of vision that feels like a shade being drawn over your eye (called amaurosis fugax) can also be a sign of a stroke or TIA about to happen. If you suspect a stroke in yourself or someone else, call 911 immediately. Speedy treatment is crucial to minimize lasting damage.

What's going on in your eyes can be a symptom of a neurological disorder. Temporary loss of vision in one eye, changes in the way your pupil reacts to bright light, or pain when you move the eye may be sign of optic neuritis, says Miller. That's inflammation of the optic nerve, and it can be a symptom of something as simple as the flu or as serious as multiple sclerosis. 

Dry eye, difficulty focusing, and sensitivity to light may be signs of Parkinson's disease, says Sumers. And patients who come in complaining of difficulty making sense of what they read may have an early symptom of Alzheimer's. "The issue isn't their vision," Sumers notes, "but that they're having trouble processing what they see."

"I always look at the eyebrows," says Miller. Losing hair at the outside of your eyebrows may be a symptom of an overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid. 

Hyperthyroidism is sometimes caused by Graves' disease, a genetic autoimmune disorder also known as thyroid eye disease (TED). Symptoms of Graves' disease include double vision, dry eye, and bulging eyes.

Treating thyroid disorders with hormone therapy can help minimize symptoms. Short-term steroids, such as prednisone, help reduce swelling and prevent blindness. Selenium supplements and artificial tears may also help.

Miller also takes an extra-close look at her patients' eyelids, which can reveal all kinds of clues. "Sometimes you'll see skin cancer in the eyelid—like a sty that doesn't go away," she explains. "Melanoma can show up in the eye, too, because there's pigment in the iris." 

Flakey, red, irritated skin around the eyelid could be a symptom of rosacea or psoriasis. Red, itchy eyes may be signs of poorly controlled seasonal allergies—also called allergic conjunctivitis. 

Kaposi's sarcoma, a rare form of cancer that develops in patients with advanced AIDS, can show up as purple lesions on the eyelids.

You'd probably notice if the whites of your eyes—your sclera—are looking yellow, or jaundiced. "That may be a sign of underlying liver disease," says Miller, such as cirrhosis or hepatitis.

But a more common cause of jaundiced sclera is pinguecula, or thickening of the clear membrane that covers the whites of the eyes. It's caused by too much exposure to the sun's ultraviolet rays, so it's another good reason to wear sunglasses to protect your eyes from sun damage.

Anything that takes a toll on your immune system is hard on your eyes, too. Dry eye can be a symptom of autoimmune disorders, such as lupus, rheumatoid arthritis, and Sjogren's syndrome. Blurred vision, double vision, floating spots, and other vision changes can be symptoms of serious infections, such as Lyme disease and HIV.

So, now you know that HCPs are looking for all kinds of things when they looks into your eyes. But you don't have to wait for your next eye exam to find out what's going on with your health. "People can look at their eyes themselves," says Miller. "If you see something that looks funky, have it checked out." 

If you notice any sudden change, such as blurred vision, or a change in how well your contacts or glasses is working, make an appointment with an eye specialist immediately. 

"Sometimes, it's a symptom of another systemic disease," says Sumers. And if it turns out to be no big deal, you'll feel a whole lot better.