Thyroid eye disease (TED) is an autoimmune disease that causes inflammation and damage to the muscles, connective tissue, and fatty tissues around the eyes. It usually affects both eyes but can sometimes impact only one. It usually affects both eyes but can affect just one.

Autoimmune diseases develop when the immune system mistakenly attacks healthy cells instead of targeting harmful invaders like bacteria and viruses. The type of cells affected determines the specific disease. For instance, in rheumatoid arthritis (RA), the immune system attacks the lining of the joints, while in TED, it targets the tissues and muscles behind the eyes.

TED-related inflammation can occur above, below, and behind the eyes. When it occurs behind the eyes, it can push them forward, leading to a bulging appearance, especially during the active phase of the disease. Other symptoms may include redness, eye pain, misalignment, light sensitivity, and double vision. However, symptoms vary from person to person.

Eye changes can develop at any time. While TED is often mild and may improve on its own, it typically follows an active and inflammatory phase lasting six months to three years. During this period, symptoms can fluctuate, with periods of worsening followed by improvement.

Once symptoms stop or stabilize, TED eye specialists may determine that the disease has progressed to the inactive or chronic phase, during which some people may not experience any symptoms, however, this does not mean that the disease has gone away. Some people may need treatment for lasting effects, like scarring or fibrosis, caused by prolonged inflammation.

TED is linked to an overactive immune response, where the thyroid gland releases too much thyroid hormone (TH). This increases stimulation of thyroid-stimulating hormone receptors (TSHR), which are mainly found in the thyroid but also in eye tissues. Rarely, TED can develop even in people with normal thyroid function.

TED affects an estimated 155 to 250 people per 100,000 worldwide. A 2022 U.S. study reported that TED is generally more common in women than men, with 16 cases per 100,000 females, compared to 2.9 cases per 100,000 males. Severe TED is more common in males, with a ratio of 4:15. TED can also be diagnosed in children, with 1.7 to 3.5 cases per 100,000.

TED is not contagious and cannot be spread from person to person. There is no cure, but treatments can help manage symptoms like pain and inflammation.

Other Names for Thyroid Eye Disease (TED)

Thyroid eye disease is sometimes referred to by different names, often including the words “Graves’” or “thyroid,” such as:

• Graves’ eye disease
• Graves’ ophthalmopathy
• Graves’ orbitopathy
• Thyroid-associated orbitopathy
• Thyroid ophthalmopathy

TED has no known specific cause, but several factors can play a role.

Genetics and Other Autoimmune Conditions

Thyroid eye disease is not necessarily inherited but autoimmune diseases tend to run in families. Different family members may develop different autoimmune diseases. For example, the cousin of a member with TED could have RA, a grandparent could have type 1 diabetes or a sibling could have psoriasis. Also, anyone with an autoimmune disease has an increased risk of developing other autoimmune diseases.

Other risk factors for developing thyroid eye disease include:

• Cigarette smoking
• Uncontrolled thyroid disease
• Treatment with radioactive iodine treatment
• Advanced age
• Stress
• Poorly controlled diabetes²

Graves’ Disease

Graves’ disease is a separate autoimmune disease, but it is often linked with TED. Roughly 30 to 40 per cent of people with Graves’ experience signs and/or symptoms of TED³ while around 90 per cent of people with TED have Graves’ disease.

In Graves’ disease, immune cells attack the thyroid gland (located in the neck). This gland produces hormones that affect many organs in the body. Graves’ disease is a common cause of hyperthyroidism (an excess production of hormones) so it can also affect the organs.

Common symptoms of Graves’ disease include:

• Weight loss, despite increased appetite
• Nervousness, irritability, trouble sleeping, fatigue
• Frequent bowel movements
• An enlarged thyroid gland
• Rapid or irregular heartbeat

Hashimoto’s Disease

Hashimoto’s disease is another autoimmune condition that affects the thyroid gland, often leading to low thyroid hormone levels (hypothyroidism). Some studies suggest that up to 6 percent of people with Hashimoto’s may also develop TED.

Common symptoms of Hashimoto’s disease include:

• Weight gain
• Fatigue
• Sensitivity to the cold
• Constipation
• Muscle pain
• Dry skin, thin hair, and/or brittle nails

Symptoms of thyroid eye disease (TED) can differ for each person and range from mild to severe. Some people experience bulging eyes, while others may have pain behind or around the eyes, especially with movement. Many people have more than one symptom at a time, with varying intensity.

Common symptoms of TED to watch for include:

Bulging Eyes (Proptosis)

One of the most common signs of TED is bulging eyes. Inflammation of the fat and tissue behind the eyes pushes them forward, making the whites of the eyes more visible. This can affect appearance and confidence.

Eye Pain or Pressure

Inflammation can cause pain or pressure in, around, or behind the eyes. This discomfort may worsen with eye movement (looking up, down, or sideways) and, in some cases, cause a feeling of pressure behind or around the eyes, leading to headaches.

Retracted Eyelids

Dry, Gritty Eyes

Dry, gritty, or irritated eyes are common symptoms of TED. They occur when the eyes don’t produce enough tears, or when tears evaporate too quickly (or both). Some people describe it as feeling like sand or dust in their eyes. Dry eyes can be a symptom of many conditions, including autoimmune diseases.

Watery, Teary Eyes (Epiphora)

Some people with TED experience excessive tearing, or epiphora, which can make vision blurry. This often happens when the eyes overproduce tears to compensate for dryness or they don’t drain properly. Excess fluid in the eyes can make it harder to see clearly.

Puffy Eyes or Eyelids (Periorbital Oedema)

Swelling around the eyes (periorbital edema) is a common symptom of TED, caused by fluid buildup from inflammation. While allergies and infections can also cause puffiness, TED-related swelling tends to be persistent. Peripheral edema occurs when the body struggles to remove excess fluid, and periorbital edema specifically refers to fluid collecting around the eyes.

Inflamed Eyelids (Blepharitis)

Blepharitis causes the edges of the eyelids to become red or dark and swollen and scaly. Inflamed eyelids is link to dry or irritated eyes as well various conditions, including allergies and dandruff.

Red Eyes or Eyelids or Bloodshot Eyes

These inflammatory symptoms are commonly associated with allergies or an infection but can also be caused by TED.

Light Sensitivity (Photophobia)

The eyes may become highly sensitive to bright light, a condition known as photophobia. This often happens when dryness or an irregular eye surface causes light to scatter, leading to discomfort. While photophobia literally means “fear of light,” medically, it refers to pain or discomfort in bright environments.

Blurry Vision

Blurry vision can have many causes, but in TED, it often results from corneal damage or swelling in the tissues and muscles behind the eye, which can put pressure on the optic nerve.

Misaligned or Crossed Eyes (Strabismus)

Inflammation of the eye muscles can cause them to become thicker and more fibrous, often restricting movement and affecting eye alignment. Misaligned or crossed eyes, or strabismus, can cause blurry or double vision. These symptoms can be temporary, situational or constant. They can be corrected if treated early and may be managed with corrective glasses.

Vision Loss

People with severe TED may experience vision loss due to damage to the optic nerve. Optic nerve dysfunction caused by TED is referred to as dysthyroid optic neuropathy (DON). Colors may fade or appear washed out, and some parts of vision may be lost. If left untreated, these symptoms may worsen and become permanent so it is important to seek treatment early.

Differences Between Thyroid Eye Disease and Other Eye Conditions

TED can sometimes be difficult to diagnose, and people may be incorrectly treated for other conditions such as allergy, hay fever, or conjunctivitis.

The following signs may indicate TED rather than another eye condition.

• Symptoms may occur in the wrong season for hay fever.
• Allergies usually cause itchy eyes, while TED does not.
• Conjunctivitis usually causes sticky eyes, which is less common in TED.
• TED is often associated with an ache or pain in or behind the eye, especially when looking up or sideways — other conditions mentioned are not.
• TED is sometimes associated with double vision, which is not common in other conditions.

It is important to know that TED affects everyone differently and it can leave some people with ongoing symptoms like eye bulging, eye pain, double vision, and pressure behind the eyes. The sooner you notice your symptoms, the quicker your doctor can help. If you feel your symptoms have been dismissed, misdiagnosed, or undertreated, seek a second opinion or ask for a referral to an ophthalmologist or endocrinologist.

There is no single lab test to diagnose thyroid eye disease (TED). Instead, doctors use several tests to rule out other conditions and understand what’s happening inside and around your eyes. These may include:

• Thyroid function tests
• Blood tests for thyroid antibodies
• CT scans (to see tissues behind the eyes)
• MRI scans (to get a detailed view of the eyes and surrounding areas)

Your doctor may also check for bulging eyes, eye pressure, and optic nerve health. Thyroid eye disease can cause the pressure inside the eye to rise, which puts you at risk for glaucoma (a group of eye diseases that can damage your optic nerve and lead to vision loss). The optic nerve is important because it sends information from your eyes to your brain.

Thyroid eye disease (TED) is a physical condition, but it can also affect mental health. Many people with TED experience anxiety, depression, or social isolation due to the visible changes it causes. Seeking support is important, and there’s no shame in asking for help.

Talking to trusted friends or family about how TED affects you can provide emotional support. You might also find comfort in joining a TED or thyroid support group, either in person or online. Connecting with others who understand your experience can help you feel less alone and may provide useful tips for managing daily life.

It is also a good idea to talk to your primary care physician about your mental health. They can offer guidance or refer you to a counselor, therapist, or mental health professional for extra support..

This information should never replace the information and advice from your treating doctors. It is meant to inform the discussion that you have with health care professionals, as well as others who play a role in your care and well-being.

Cleveland Clinic: Blepharitis. https://my.clevelandclinic.org/health/diseases/10032-blepharitis

Cleveland Clinic: Dry Eye. https://my.clevelandclinic.org/health/diseases/24479-dry-eye

Cleveland Clinic: Epiphora (Watery Eyes). https://my.clevelandclinic.org/health/diseases/17944-epiphora-watery-eyes

Cleveland Clinic: Proptosis (Bulging Eyes). https://my.clevelandclinic.org/health/diseases/proptosis-bulging-eyes

Cleveland Clinic: Thyroid Eye Disease. https://my.clevelandclinic.org/health/diseases/17558-thyroid-eye-disease

EyeWiki: Dysthyroid Optic Neuropathy. https://eyewiki.org/Dysthyroid_Optic_Neuropathy

Mayo Clinic: Graves’ Disease. https://www.mayoclinic.org/diseases-conditions/graves-disease/symptoms-causes/syc-20356240

Jamal I. Hashimoto’s Thyroiditis Associated Thyroid Eye Disease: A Success Story of Teprotumumab, Journal of the Endocrine Society, Volume 5, Issue Supplement_1, April-May 2021, Page A932, https://academic.oup.com/jes/article/5/Supplement_1/A932/6241103

Mayo Clinic: Hyperthyroidism (overactive thyroid), https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659

Moleiro AF, et al. Tocilizumab as a Useful Tool for Thyroid Eye Disease in Pediatric Population: A Case Report. Case Rep Ophthalmol. 2022 Nov 17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9710467

Kossier et al. Endocrine Society. Patient Resources. Thyroid Eye Disease. 2022 January 24. https://www.endocrine.org/patient-engagement/endocrine-library/thyroid-eye-disease

Osaki TH, Monteiro LG, Osaki MH. Management of eyelid retraction related to thyroid eye disease. Taiwan Journal of Ophthalmology. 2022 Feb 14. doi: https://doi.org/10.4103/tjo.tjo_57_21.

Royal Australian College of General Practitioners: Clinical Practice. Therapeutic Review. Thyroid Orbitopathy. https://www.racgp.org.au/getattachment/e10a3bd8-a800-4a53-8635-1bf0764912d6/attachment.aspx

Szelog J, Swanson H, Sniegowski MC, Lyon DB. Thyroid Eye Disease. Mo Med. 2022 Jul-Aug. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9462910/#b7-ms119_p0343

Thyroid Eyes: Thyroid Eye Disease Phases. https://www.thyroideyes.com/about-thyroid-eye-disease/phases-of-ted#:~:text=Thyroid%20Eye%20Disease%20may%20slow,your%20condition%20has%20gone%20away

Thyroid Eye Disease: Sensitivity to Light. https://thyroideyedisease.net/light-sensitivity

Thyroid Eye Disease: Vision Changes. https://thyroideyedisease.net/vision-changes