Most of us know the importance of regular eye exams for keeping eyes healthy, but did you know that they can sometimes provide surprising clues about your overall health?

During a comprehensive eye exam, changes in the retina, optic nerve, blood vessels and surrounding tissues may give your eye-care professional a reason to recommend further evaluation in other areas of your body.

1. High Blood Pressure

High blood pressure can affect blood vessels throughout the body, including the small vessels within the retina at the back of the eye.

During a dilated eye exam, an eye-care professional may notice changes in retinal blood vessels that can be associated with hypertension. Because high blood pressure can occur without obvious symptoms, regular medical screenings remain important even when you feel healthy.

2. Diabetes

Diabetes can affect the small blood vessels in the retina.

Over time, high blood sugar can damage these vessels, potentially causing them to swell, leak or develop other abnormalities. This condition is known as diabetic retinopathy.

Diabetic retinopathy may not produce noticeable symptoms during its early stages, which is one reason regular dilated eye exams are particularly important for people with diabetes.

3. High Cholesterol

Certain lipid deposits can sometimes become visible in or around the eyes.

One example is corneal arcus, a white, gray or bluish ring around the outer edge of the cornea. It becomes increasingly common with age and doesn't necessarily indicate high cholesterol in older adults.

When it appears in a younger person, however, an eye-care professional may recommend evaluation for elevated cholesterol or other lipid abnormalities. High cholesterol itself requires appropriate medical evaluation and blood testing to diagnose.

4. Thyroid Eye Disease

Thyroid eye disease is an autoimmune condition affecting the muscles and tissues surrounding the eyes and is commonly associated with Graves' disease.

Possible symptoms can include:

• Dry or irritated eyes
• Redness
• Swelling around the eyes
• Bulging or prominent-looking eyes
• Eyelid changes
• Double vision
• Difficulty moving the eyes normally

Significant changes involving eye position, movement or vision should be evaluated by a healthcare professional.

5. Autoimmune Conditions

Autoimmune diseases can cause inflammation in different parts of the body, including the eyes.

Conditions such as Sjögren's disease, rheumatoid arthritis and lupus may be associated with problems ranging from significant eye dryness to inflammation affecting different structures of the eye.

Persistent redness, significant pain, light sensitivity or severe dryness should be evaluated rather than simply dismissed as everyday irritation.

6. Neurological Conditions

The eyes and brain are closely connected. The optic nerve carries visual information from the eye toward the brain, while other nerves help control eye movement and pupil responses.

Changes involving vision, eye movement, the optic nerve or pupils can sometimes prompt doctors to investigate a possible neurological cause.

One example is optic neuritis, an inflammation of the optic nerve that can occur on its own or in association with certain neurological conditions, including multiple sclerosis. Symptoms may include blurry or reduced vision, changes in color perception and pain when moving the eye.

7. Blood Vessel and Circulation Problems

The retina depends on a healthy blood supply, so problems affecting circulation can sometimes produce visible changes within retinal blood vessels.

Depending on the finding, an eye-care professional may recommend additional medical evaluation.

Sudden vision loss, a new blind spot or a curtain-like shadow moving across your vision requires prompt medical attention.

8. Certain Nutritional Deficiencies

Nutrition plays an important role in normal eye function.

Vitamin A, for example, contributes to normal vision and helps maintain tissues on the surface of the eye. Severe vitamin A deficiency can contribute to problems including difficulty seeing in low light and significant eye dryness.

Severe deficiency is relatively uncommon in the United States but can occur under certain medical or nutritional circumstances.

9. Medication-Related Eye Changes

Some medications can affect the eyes.

Depending on the medication, potential effects may involve the retina, optic nerve, lens or surface of the eye. Certain medications can also affect pressure within the eye.

Never stop taking a prescribed medication because you're concerned about your eyes without first speaking with your healthcare provider. Instead, ask whether your medications require periodic eye monitoring and report new or unusual vision symptoms.

10. Certain Infections

Some infections affecting the body can also involve the eyes.

Depending on the cause, symptoms may include:

• Redness
• Inflammation
• Light sensitivity
• Eye discomfort
• Changes in vision

Because many different conditions can cause similar eye symptoms, an examination may be necessary to determine the underlying cause.

11. Blood and Clotting Disorders

Conditions affecting normal bleeding, clotting or circulation can sometimes produce changes in or around the eye.

These can range from bleeding on the surface of the eye to abnormalities involving the retina.

A bright-red patch on the white of the eye, known as a subconjunctival hemorrhage, is often harmless and may resolve on its own. However, recurrent episodes or bleeding accompanied by other concerning symptoms should be discussed with a healthcare professional.

12. Some Cancers

Although much less common than everyday vision problems, cancer can occasionally affect structures in or around the eye.

For example, intraocular melanoma, or uveal melanoma, is a rare cancer that develops inside the eye. Abnormal growths or suspicious changes can also occur around the eyelids and surrounding tissues.

An unusual finding during an eye exam doesn't mean someone has cancer. However, an eye-care professional may recommend further testing when something requires closer evaluation.

Why Can the Eyes Reveal So Much?

Your eyes don't function independently from the rest of your body. They depend on healthy blood circulation, nerve function, immune activity and nutrition.

During a comprehensive eye exam, an eye-care professional can evaluate structures including the retina, optic nerve, retinal blood vessels, cornea, lens and surrounding tissues. Changes in these areas can sometimes provide information that warrants further investigation.

An Eye Exam Isn't a Full-Body Diagnostic Test

Seeing a particular change in the eye doesn't necessarily mean you have a specific disease.

Many eye findings have more than one possible explanation. Instead, an unusual finding may help your eye-care professional determine whether additional testing or evaluation by your primary care provider or another specialist is appropriate.

Don't Wait for Your Vision to Change

It's easy to assume that if you can see clearly, your eyes must be healthy. But some eye conditions can develop without noticeable symptoms during their early stages.

How often you need a comprehensive eye exam depends on factors such as your age, medical history and individual risk factors. People with certain medical conditions, including diabetes and high blood pressure, may need more frequent eye examinations.

Between appointments, don't ignore sudden changes.

Sudden vision loss, new double vision, severe eye pain, flashes of light, a sudden increase in floaters or a curtain-like shadow across your vision should be evaluated promptly.

The Bottom Line

Your eyes do much more than help you see the world around you. Because they contain blood vessels and nerve tissue and are connected to numerous systems throughout the body, they can sometimes provide healthcare professionals with valuable clues about your overall health.

An unusual finding doesn't automatically mean something serious is wrong, but it may provide an important reason to investigate further.

Taking care of your eyes is part of taking care of your overall health.