In medical terms, thyroid eye disease (TED) is also called Graves’ eye disease or Graves’ ophthalmopathy. It causes swelling in the eye muscles and affects the connective and fatty tissues behind or around the eyes, making the eye appear bulged or reddened. As the name suggests, TED occurs due to an overactive thyroid gland. There are several risks, early signs, and causes that one should be aware of to receive timely treatment for the condition. What is TED? It is an autoimmune eye disorder often triggered by thyroid dysfunction, wherein a person’s immune system targets and attacks the thyroid gland, prompting it to release excessive thyroid hormone. As a result, the thyroid gland enlarges. One usually experiences two phases of the condition. First, an individual may experience an active phase where the inflammation peaks and symptoms worsen, which can last up to three years, followed by the stable phase. Warning signs of TED The warning signs of TED may affect both or even a single eye. Here are some of the common signs to look out for: 1. Changes in eye structure The eyes may bulge out or just generally look out of line. This can also lead to double vision or even blindness in some cases due to the constant pressure of the swelling on the delicate eye nerves at the back.