Thyroid eye disease (TED) is a progressive autoimmune disease where the immune system attacks itself. In TED, the body’s immune system mistakes healthy tissue around the eyes for harmful invaders, such as germs. The result is damage and inflammation in and around the eyes.1
Damage from TED leads to various symptoms relating to the eyes, including pain, pressure, and irritation. In rare cases, TED can impact your vision. Optic nerve compression or optic neuropathy can occur from the pressure and swelling caused by TED.1
TED and optic nerve compression
Both of your eyes have optic nerves. The optic nerve is a bundle of nerve fibers that serves as a highway for signal transmission between your eye and brain.2,3
On rare occasions, swelling of the fat and tissues behind the eye that occurs in the active (acute) phase of TED can affect the optic nerve. Pressure from the swelling can squeeze (compress) the optic nerve, which can result in vision loss if not immediately found and treated. Additionally, the swelling from TED can cause the eyes to bulge out of the sockets, a condition called proptosis (prop-toe-sis).1,4
Symptoms
The most common symptom of optic nerve compression is vision loss, which can be gradual and occur over time. Vision loss can present in many different ways, including:5
- Blurred vision
- Double vision (diplopia, dip-low-pee-uh)
- Changes in peripheral vision, or more of a “blind spot”
- Decreased ability to see different colors (color vision)
Diagnosis
Your doctor or TED specialist will perform various tests to diagnose and confirm optic neuropathy including:
History and physical exam
Before performing the physical exam, your doctor or TED specialist will ask you questions about your current symptoms and your past medical history.
Your TED specialist or ophthalmologist will also use an ophthalmoscope to look for signs of damage or disease on the optic nerve. The ophthalmoscope is used to visualize the back of the eye and optic nerve. Sometimes, your doctor uses eye drops to enlarge (dilate) your pupils to get a better look at the back of the eye.2,3,5
Diagnostic imaging
Advanced diagnostic imaging like computed tomography (CT) or magnetic resonance imaging (MRI) will help your TED specialist visualize your eyes, bony structures, and soft tissue.5
Treatment
Seeing a TED specialist or your ophthalmologist as quickly as possible is the first step in treating optic nerve compression.
Steroid therapy
Steroids are strong anti-inflammatory drugs. When given in doses higher in amount than your body normally makes, steroids quickly decrease inflammation.6
In TED, high-dose steroids are vital to help prevent vision loss and decrease severe swelling and inflammation during the acute phase. During this phase, swelling of the fat and tissues behind the eye can squeeze and damage the optic nerve in the eye. Optic nerve compression is an emergency and can lead to vision loss if not quickly treated.1
Decompression surgery
Known as orbital decompression, this minimally invasive procedure relieves eye bulging and helps to decrease pressure on the optic nerve. In this procedure, the TED specialist surgeon removes some of the fat and bones in the eye socket that have been damaged by TED. The doctor then reconstructs and repositions the eye into a normal position.7
Disease-modifying drugs
Disease-modifying anti-rheumatic drugs (DMARDs) are drugs used to treat inflammatory or immune diseases. There are 2 kinds of DMARDs, traditional (also called synthetic) and biologics.8
Biologics are drugs made from living cells. These cells can come from parts of the blood, proteins, viruses, or tissue. The process of making biologics turns these cells into drugs that can prevent, treat, and cure some diseases. Drugs similar in structure to known biologic drugs are called biosimilars.
As of September 2021, TepezzaⓇ (teprotumumab-trbw) is the biologic approved by the U.S. Food and Drug Administration (FDA) to treat TED. Tepezza is a monoclonal antibody. Monoclonal antibodies work by acting like proteins made by your immune system.9
Tepezza blocks a receptor in the body that can be “turned on” when there is too much thyroid hormone in the blood. This receptor is called insulin-like growth factor-1 (IGF-1R). Turning on IGF-1R leads to growth of muscle, fat, and connective tissue cells around the eyes. Too much growth of these cells causes the symptoms of TED.9
Tepezza is classified as an insulin-like growth factor-1 inhibitor. By blocking IGF-1R, Tepezza decreases the muscle, fat, and connective tissue swelling that is common in TED.9
Stabilize thyroid hormone levels
Many people with TED have abnormal thyroid function. However, this is not always the case. Keeping your thyroid hormone levels normal might help with general health and can be prioritized by your TED specialist, family doctor, and endocrinologist (doctor who treats hormone conditions). Despite this, treating TED is different from treating hormone dysfunction, and stabilized thyroid function may not result in decreased TED symptoms.1
TED is a complex condition that varies from person to person. Although rare, optic nerve compression from TED is a serious and sight-threatening complication. An ophthalmologist or TED specialist should immediately assess any changes in your vision.