Signs in your eyes that could mean you’ll develop diabetes and cancer

The eyes are the window to the soul, but they may also be the key to spotting deadly diseases, doctors warn. 

Dark specks on the iris could just be a sign of too much summertime sunshine. But in rare cases, they could be the first clue to spotting deadly eye cancers.

Additionally, subtle yellowing around the whites of the eyes could indicate that the liver can’t properly filter out toxins, which may lead to permanent scarring.

And though red blotches are often a sign to get some more sleep and lay off the screen time, they could also suggest high blood pressure or cholesterol has damaged your blood vessels.

Doctors told the Daily Mail that many of America’s deadliest illnesses can be spotted with a simple eye exam, even before other symptoms appear.

Diabetes, high blood pressure, high cholesterol and heart disease may attack blood vessels in the eyes and lead to redness or bright blotches. 

Dark or bright spots on the eye or thickness or swelling around the eyelid, meanwhile, could indicate eye cancer before signature vision changes occur.

And though most Americans can go a year or two without an exam, people with chronic diseases like diabetes should visit the eye doctor at least once a year to check for crucial signs of the condition worsening.

Dr Raj Dasgupta, chief medical officer for Sleepopolis, told the Daily Mail: ‘A lot of diseases that affect the whole body can leave clues in the eyes because the eyes have tiny blood vessels, nerves and tissues that are really sensitive to changes.’

Dr Jacqueline Bowen, president-elect of the American Optometric Association, estimates eye doctors can detect 270 health conditions that aren’t directly related to the eyes.

She told the Daily Mail diabetes is one of the most common diseases found through a routine eye exam.

In 2019, for example, eye doctors detected 431,000 cases of diabetes in patients who didn’t know they had the disease. 

Suffered by 40 million Americans, diabetes leads to consistently high blood sugar that can damage blood vessels in the eyes.

Similarly, high blood pressure can narrow and weaken eye blood vessels and cause them to leak or rupture, Dr Dasgupta said.  

This is called diabetic retinopathy, the leading cause of blindness in working-age adults, according to the CDC.

While it may be undetectable just by looking in the mirror, in some cases it can cause blood vessels to leak into the whites of the eyes, making them red and blotchy. 

And though the skin cancer melanoma is one of the most common cancers in the US, affecting 100,000 Americans and killing 8,000, in rare cases, it can affect just the eye. 

Ocular melanoma develops in the eye’s middle layer, the uvea. This area contains melanocytes, which produce melanin, a pigment that gives skin its color. Higher concentrations of melanin are associated with darker skin.

Dr Dasgupta said ocular melanoma can appear as ‘a dark spot or growth inside the eye’ during a routine eye exam and often has no other symptoms.

If symptoms do occur, they include flashes of light, a change in pupil size, blurry vision or loss of peripheral vision.  

Retinoblastoma, a rare cancer that grows in the back of the eye due to a genetic mutation, often shows up as a bright white spot in photos and on scans.

A Canadian mother named Steph, for example, caught the glow in her toddler’s eye in 2021 after snapping a picture of her.

The cancer affects 200 to 300 Americans per year, most of whom are under two years old. It has a 96% survival rate, and removing the affected eye keeps it from spreading.

Breast and lung cancers have also been shown to spread to the eye, causing dark spots on the eye and leading to vision loss. 

Additionally, rheumatoid arthritis is an autoimmune inflammatory condition that attacks the joints, but that inflammation can also travel to the eyes.

Ocular inflammation causes the eye and its surrounding tissues to become red, swollen and irritated like during an allergic reaction. 

Over time, rheumatoid arthritis can also increase pressure inside the eye, which may raise the risk of glaucoma, a type of vision loss that makes the eyes look cloudy or hazy.

General signs of vision issues include ‘unusual trouble adjusting to dark rooms, difficulty focusing on near or distant objects, squinting or blinking due to unusual sensitivity to light or glare, recurrent pain in or around eyes, double vision, and excess tearing or watery eyes,’ Dr Bowen said. 

Dr Dasgupta said while most healthy Americans can get by with an eye exam every two to three years, those at risk of conditions like diabetes and high blood pressure should ‘100%’ get an exam every year. 

‘The eyes can give us early warning signs of these conditions before you notice anything wrong with your vision. And catching those changes early can help protect your eyesight and overall health,’ he said.