Thyroid Eye Disease (TED) is an autoimmune disease that affects some people with autoimmune thyroid disease. TED is most common in people with hyperthyroidism due to Graves’ disease and rarely may occur in patients with normal or low thyroid levels. TED is an eye disorder that causes inflammation and damage to the tissues around the eye, including muscles, fatty tissue, and connective tissue. The inflammation can push the eyes forward, causing a "staring" or "bulging" appearance. Symptoms of TED include feeling of grittiness in the eyes, pain behind the eyes or with eye movement, redness of the eyes, dry eyes, extra tearing of the eyes, puffy or red eyelids, forward bulging of the eyes, and seeing double. TED has two phases: the active or inflammatory phase and the stable phase. The active phase can last for months up to three years, while the stable phase follows when the inflammation stops. TED is usually mild and gets better on its own over time, but some cases can be quite severe and require medications or surgery. Treatment may include medications, lifestyle changes, or surgery. The most important lifestyle change one can make is to quit smoking if they smoke, as it raises the risk of developing TED by seven to eight times and makes TED’s active (inflammatory) disease phase longer. If one notices any of the symptoms of TED, they should contact their doctor immediately, as TED can cause serious eye damage if left untreated.