You've probably wondered why your eyes need to be dilated when you visit your eye doctor. Your eye doctor thoroughly examines all parts of the eye when it is dilated, and might discover conditions that affect your overall health.

During your eye exam, eyedrops are used to widen your pupils. This allows your doctor to see into the back of your eye. Here's what happens when the eye doctor dilates your eyes:

The eye doctor examines your retina. The retina is the layer at the back of the eyeball. There you find a network of vessels and nerves which connect with different parts of the body. 

The eye doctor examines the condition of the optic nerves. The optic nerves are a pair of nerves located just below the brain. They transmit vision-related information to the brain where it's translated into images. 

The eye doctor examines the condition of the macula. The macula is found near the center of the retina, and allows you to see objects that appear in your center of vision. When your eyes are dilated, your doctor looks for signs of macular degeneration. As many as 11 million Americans have some form of the disease.

Your eye doctor looks for signs of disorders that affect other parts of the body. Your doctor examines blood vessels and nerves leading to and coming from areas of the eye that connect with other systems of the body. In fact, your eye doctor may be the first medical professional to see signs of chronic health disorders that are not commonly associated with the eyes.

Why does the eye doctor dilate your eyes?

Now that you know what the doctor looks at, here are some of the conditions that your doctor looks for in a routine eye examination:

• Vision-related issues: Besides macular degeneration, your eye doctor looks for signs of glaucoma, eye tumors and other disorders.
• Diabetes: Tiny blood vessels in the retina can bleed or leak other fluids, which may indicate that the patient has diabetes.
• Tumors in the pituitary gland: The pituitary gland is located at the base of the brain. A growth in the pituitary gland can press upon the optic nerves, causing vision problems.
• Autoimmune diseases: Your eye doctor may find signs of autoimmune conditions such as Multiple Sclerosis, Lupus, and Crohn’s Disease.
• Arthritis: Some types of arthritis (another autoimmune disorder) are associated with the inflammation of the iris.
• High blood pressure: A dilated eye exam helps reveal thickening and narrowing blood vessels around the eye. These conditions restrict blood flow and contribute to high blood pressure.
• High cholesterol: When your eyes are dilated, your eye doctor can detect pieces of cholesterol or plaque in the arteries of the retina.

These are just a few of the chronic health issues that an eye doctor can run into during a dilated eye exam. For this reason, it is recommended that children and adults receive eye exams routinely. As a result, there is a better chance for early detection and treatment.