Thyroid eye disease (NORD)

Thyroid eye disease is a rare disease in which progressive inflammation damages muscle, fat and connective tissues around the eyes.

The disease has an active phase, which can last from six months to two years, where inflammation, swelling, and damage occur.

The inactive phase occurs when disease progression stops, but the tissue damage and symptoms remain.

Signs and symptoms can vary between individuals, but commonly the white parts of the eyes are inflamed.

A particularly noticeable change is the eyes appear to be bulging out of the eye socket, called exophthalmos or proptosis, which makes a person appear as if they are always ‘staring’.

Additionally, the eyes can feel irritated, uncomfortable, and have a “gritty” feeling.

They may also be constantly watery or be dry.

The eyelids can become inflamed and retracted, so they won’t close completely and blinking or trying to close the eyes can be painful.

Vision changes may also occur, including blurry vision; double vision; or an intolerance to bright lights.

In severe cases, vision may be threatened from increased pressure on the main nerve of the eye that carries visual information to the brain; or from dryness leading to erosion of the cornea, which is the outer part of the eye.

Thyroid eye disease usually occurs during middle age.

While it’s more frequent among females, males tend to have more severe cases.

Environmental factors such as smoking may contribute but there’s also a variety of genetic factors.

Individuals may have an elevated risk if they also have immune diseases like type 1 diabetes or rheumatoid arthritis.

Because thyroid eye disease occurs so often with Graves’ disease, it’s also called Graves’ orbitopathy, Graves’ ophthalmopathy, and thyroid-associated ophthalmopathy.

The exact underlying process by which thyroid eye disease occurs is not fully understood, but like Graves disease, it’s an autoimmune disorder.

Normally, the immune system protects the body by identifying and destroying foreign invaders; like bacteria, viruses or toxins.

The adaptive immune system is in charge of creating specialized proteins, called antibodies, that attack and destroy specific invaders.

But in autoimmune disorders, the adaptive immune system mistakenly attacks the body’s own healthy tissues.

In thyroid eye disease, the immune system makes abnormal antibodies called thyroid-stimulating immunoglobulin.

And they circulate around the body and attach to specific receptors on the thyroid and other tissues, like those found in the eyes.