Your eyes don't just help you see or express how you're feeling (think: a well-timed eye roll or wink). They can also say a lot about your overall health.
In fact, "when an eye doctor looks into your eyes, they can see your blood vessels, your optic nerve and much more, which can give insight to the health of the rest of your body," says Ashley Brissette, MD, an ophthalmologist and founder of Daily Practice.
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Turns out, eye issues are often one of the first signs of other underlying medical problems. But thankfully, eye doctors can spot these issues during a routine eye exam, and recommend further testing from a specialist or your primary care doctor.
Here, learn the most common health conditions eye doctors can spot from the look of your eyes.
Diabetes causes changes to the blood vessels in your retina — the layer of cells in the back of your eye, Dr. Brissette says.
If your eye doctor notices these vessels leaking yellow fluid or blood, you could have something called diabetic retinopathy, per the AAO.
Other symptoms of diabetic retinopathy include the following, per the Mayo Clinic:
- Spots or dark strings floating in your vision (i.e., floaters)
- Blurred vision
- Dark or empty areas in your vision
- Vision loss
In order to help prevent vision problems, it's important to make sure you're managing your diabetes, and seeing your eye doctor regularly to catch issues early.
A thorough eye exam can catch certain cancers that happen on the surface or inside of your eye, Dr. Brissette says.
Skin cancers like basal or squamous cell and melanoma can affect your eyelids and outer tissues of your eye, per the AAO. In fact, about five to 10 percent of all skin cancers happen on the eyelid, per the American Society of Clinical Oncology (ASCO).
- A spreading growth on the eyelid that can be red, pink, brown or black
- Broken skin on the eyelid that does not heal
- Change in appearance of the eyelid skin (for instance, a change in color or texture)
- Chronic infection of the eyelid
- Loss of eyelashes
- Swelling or thickening of the eyelid
Certain blood cancers like leukemia (in blood cells) and lymphoma (in your lymphatic system) can also affect the inner structures of your eye. And malignant tumors in your breast or other parts of your body can metastasize (i.e., spread) to your eye region, too, per the AAO.
A stroke happens when an artery is blocked (called an ischemic stroke) or when a blood vessel leaks or bursts (called a hemorrhagic stroke), per the Mayo Clinic.
Any changes to the blood vessels of your heart and brain will likely affect the small vessels in your eyes, too, including blockages and clots. Both can put you at an increased risk of stroke, Dr. Brissette says.
Thankfully your eye doctor can see blockages or clots in your retina — which can sometimes result in blind spots in your vision — and refer you to a doctor for treatment to potentially lower your risk of stroke, per the AAO.
And if you've already had something called a "mini stroke," also known as a transient ischemic attack, you may have a temporary loss of vision, which your eye doctor can also detect.
Treating these "mini strokes" can help decrease your risk of a bigger stroke down the line, Dr. Brissette says.
4. Heart Disease
Your eye doctor may be able to tell if you have heart disease by examining the innermost layer of your eye.
This is exactly what happened in a March 2021 study in eClinicalMedicine. Researchers found that people with heart disease tend to have lesions on their retina caused by decreased blood flow — a common side effect of heart disease.
When this happens, there can be a lack of blood flow to your eye, which kills retina cells and leaves permanent, microscopic marks on the eye, per UC San Diego Health.
5. High Cholesterol
"Fatty deposits on your eyelids, natural oils on the outer part of your cornea (called arcs) or fat deposits in the back of the eye can all be signs of high cholesterol," Dr. Brissette says.
High cholesterol can even appear as a yellow or blue ring in your cornea — the clear, dome-shaped part at the front of your eye, according to the AAO.
It's important to catch high cholesterol early because it can increase your chances of serious health issues like stroke.
6. High Blood Pressure
"High blood pressure causes changes to the appearance and function of the small blood vessels inside the back of your eye," Dr. Brissette says.
In fact, hypertension (aka, high blood pressure) can look like abnormal bends, kinks or bleeding from the blood vessels in the back of your eye structure, according to the AAO.
Like high cholesterol, catching high blood pressure in its early stages is important because it's a risk factor for other eye-related issues like glaucoma, diabetic retinopathy and macular degeneration, per the AAO.
7. Vitamin A Deficiency
Vitamin A helps keep your eyes moisturized and lubricated, so a vitamin A deficiency could contribute to irritated, dry eyes, which your eye doctor can see in an exam.
This deficiency could also prevent your retina from working properly, which could lead to things like night blindness, per the AAO.
In general, vitamin deficiencies could have a negative effect on your optic nerve and lead to vision changes, Dr. Brissette says. Blood work is typically recommended to make sure you don't have any deficiencies.
8. Thyroid Problems
Your eye doctor may be able to tell if you have a thyroid issue by looking at the shape and outer appearance of your eyes, Dr. Brissette says. In fact, eye issues are so common with thyroid disease that they can be classified as thyroid eye disease.
"Thyroid eye disease causes thickening of the muscles that control eye movements as well as the tissue around the eyes, which can cause bulging or protruding eyeballs and retracting eyelids," Dr. Brissette says.
Other signs of thyroid eye disease include the following, per the AAO:
- Dry eye
- Vision changes (blurry vision or vision loss)
- Bags around the eyes
If your eye doctor notices these signs and you haven't been diagnosed with thyroid disease, they will refer you to a primary care doctor or endocrinologist for blood work and further testing.
9. Sexually Transmitted Infections
Believe it or not, your sexual health can affect your eyes.
Sexually transmitted infections (STIs) "can cause conjunctivitis (pink eye) or infections in your eye as well as inflammation inside your eye," Dr. Brissette says.
For example, syphilis, herpes, chlamydia, HIV, gonorrhea, genital warts and pubic lice can affect the layers of the eye, according to the AAO.
Your eye doctor may be able to see the eye infection or inflammation, prescribe antibiotic drops and refer you to a primary care doctor for STI testing.
10. Multiple Sclerosis
Multiple sclerosis (MS) is a rare autoimmune disease that affects your central nervous system. This means it can negatively affect one of the main nerves of your eye — the optic nerve, Dr. Brissette says.
This can manifest as inflammation in your eyes, called optic neuritis, she adds. Symptoms typically include blurry vision, pain with eye movement and less vivid color perception, Dr. Brissette says.
If you're showing other signs of a neurological disorder like MS, your eye doctor will refer you to a primary care doctor or a neurologist for more testing.
11. Rheumatoid Arthritis
You may associate arthritis with joint pain, but rheumatoid arthritis (RA) specifically can also affect your eyes.
RA is a form of arthritis that damages collagen — the essential element of connective tissue and the main component of your eye's sclera (i.e., the white part of the eye) and cornea, per the AAO.
"This can cause inflammation, pain and redness on the surface of your eye and on the inside of your eye," Dr. Brissette says. RA "is also a common cause of eye dryness," she adds.
12. Other Autoimmune Disorders
In addition to thyroid disease and rheumatoid arthritis, other autoimmune conditions can contribute to eye issues as well.
Certain autoimmune diseases that present with ocular symptoms include, per the AAO:
- Lupus (a chronic autoimmune condition that triggers inflammation throughout your body): It can cause dry eye and swelling in the white part of the eye, the middle layer of the eye or the back of the eye.
- Sjögren's syndrome (an autoimmune disease that causes the body's white blood cells to attack tear and saliva glands): It can cause dry eye, burning or stinging in the eyes and blurry vision.
- Myasthenia gravis (a chronic autoimmune disorder that causes muscle weakness): It can cause drooping eyelids in one or both eyes and double vision.
Can Brain Tumors Be Seen With Eye Exams?
In rare cases, depending on their placement, brain tumors can be detected through an eye exam at the eye doctor's office. This is because tumors close to the eye can cause increased pressure, and swelling on the nerves in the eye can be seen, Dr. Brissette says.
Other eye symptoms that could point to a brain tumor include loss of side vision, sudden double vision or changes in pupil size, per the AAO.
In this case, an MRI or PET scan of your brain would be needed, to determine the location of the tumor and the kind of treatment you'd needed.
How Often Should You See Your Eye Doctor?
If you have decent vision, it's understandable that going to the eye doctor wouldn't be at the top of your priority list.
But it's important that every adult gets a comprehensive eye exam at age 40, when early signs of disease or vision changes start to crop up, according to the AAO.
And if you're at risk for diabetes, high blood pressure or have a family history of eye disease, you should get your eyes checked before you turn 40, per the AAO.
After 40, Dr. Brissette says you should try to schedule an eye exam every two to four years if you have good vision. Older adults between ages 55 and 64 should go every one to three years, and after age 65, every one to two years, she says.
The bottom line: Regular eye exams can help catch diseases early before they cause a loss of vision or other serious health issues.
- American Society of Clinical Oncology: “Eyelid Cancer: Statistics”
- Stanford Medicine: “Eyelid Cancer”
- Mayo Clinic: “Stroke”
- eClinicalMedicine: “Prevalence of subclinical retinal ischemia in patients with cardiovascular disease – a hypothesis driven study”
- UC San Diego Health: “Heart Disease is in the Eye of the Beholder”
- American Academy of Ophthalmology: “What Is Thyroid Eye Disease (TED) or Graves' eye disease?”
- American Academy of Ophthalmology: “Arthritis and Your Eyes”
- Mayo Clinic: "Diabetic Retinopathy"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.