Your eyes can shed much light on the state of your overall health. A recent study suggests that your annual eye exam may provide insight into your risk for developing Alzheimer's disease and dementia. Researchers linked common eye conditions such as glaucoma, age-related macular degeneration, and diabetic retinopathy to an increased risk of developing Alzheimer's.

"My view, and one of the possible explanations that the authors present, is that these three eye diseases and Alzheimer's and dementia have a joined etiology or causative factor," Dr. Albert Hofman, chair of epidemiology at the Harvard T.H. Chan School of Public Health, reveals in Harvard Health Publishing. "All are linked to cardiovascular disease."

But Dr. Cary Silverman, medical director of EyeCare 20/20, in New Jersey, tells Newsmax that there may be an even more subtle underlying cause for the link.

"My take is that Alzheimer's disease most likely has an inflammatory factor, as does heart disease," he says. "Inflammation may also play a part in diabetes, certain types of glaucoma, and macular degeneration. Therefore, they do have a similar causative factor and if your eyes reveal one symptom, chances are you are at risk of developing others."

Here are seven diseases that may be detected by an eye exam:

1. Diabetes. An exam can determine the health of blood vessels in the back of your eyes. Dilating the eyes is also the only way to detect diabetic retinopathy.
2. High blood pressure. If the doctor notices blood vessels are crossed or compressed, it could be a sign of hypertension.
3. Stroke. Doctors can detect symptoms such as a microscopic clot in the blood vessels of the retina, which could indicate a more dangerous clot elsewhere.
4. Thyroid disorders. An eye exam could reveal if a patient has thyroid issues based on how much both eyes bulge from inflammation of the cells.
5. Cancer. Several types of cancer can be detected during an eye exam. For example, ocular melanoma can be spotted during a dilated examination of the eye using bright light and a magnifying glass.
6. High cholesterol. A piece of cholesterol or plaque may be seen in the arteries of the retina after the doctor has dilated your eyes. This can indicate plaque in other areas of your body, which could lead to heart attack and stroke.
7. Arthritis. The same inflammation that damages your joints can also affect your eyes. "The eye is like a microcosm of the entire body within a small ball," Sunir J. Garg, M.D., retina surgeon at Wills Eye Hospital in Philadelphia says in an article published by the Arthritis Foundation. "Any inflammatory condition that affects collagen — the main component of connective tissue — such as rheumatoid arthritis, can affect the sclera or white of the eye and the cornea or lens cap, which are basically entirely collagen." The earlier you detect the problem, the more successful the treatment.

The American Academy of Ophthalmology recommends that all adults get a baseline eye exam by the age of 40 when early signs of disease and vision changes start to occur. Adults 65 years and older should have a comprehensive eye exam every year or two or as recommended by their ophthalmologist.