Our immune system can ward off external threats such as pathogens and infections while sparing our host tissues. A disruption of this intricate balance between ‘self’ and ‘non-self’ leads to autoimmune disease. In autoimmune diseases, the body’s immune system begins to attack itself. Thyroid eye disease (TED) is one such complex autoimmune condition affecting the tissues around the eyes and is commonly associated with other thyroid conditions, such as Graves’ disease (1). It is characterized by inflammation, pain, swelling or protruding eyeballs (proptosis), eyelid retraction or inability to close the eyes completely, eye surface dryness, double vision (diplopia), and in severe cases, compression of the optic nerve (2). But despite being well described in medical literature, TED is frequently misdiagnosed or diagnosed late, leading to delayed treatment and affecting the efficacy of interventions (3). Understanding both TED and the factors affecting delayed/misdiagnosis is key to improving outcomes both for patients and clinicians.
The following article outlines some of the most common reasons behind the misdiagnosis or late diagnosis of TED and what healthcare providers and patients can do about it.
TED Presents with Wide and Variable Symptoms
One of the main reasons TED is misdiagnosed is that its symptoms may occur over time, are heterogeneous and non-specific, meaning that they vary widely from person to person and can overlap with other more common eye conditions. In the early, active phase of TED, patients may experience:
- Dry or gritty eyes
- Redness or irritation
- Eyelid swelling or retraction
- Pain around the eyes
- Sensitivity to light
- Double vision (diplopia)
- Increased tearing or blurred vision
These non-specific symptoms can easily be mistaken for dry eye disease, allergic conjunctivitis, blepharitis, or simple eye strain. This is particularly true if the patient also has a coexisting thyroid disorder that is undetected. In fact, TED may present before any obvious thyroid dysfunction, and nearly 20% of patients experience eye symptoms before their thyroid disease is diagnosed. This contributes to the delays or incorrect diagnoses when thyroid disease has not yet been recognized.
Symptoms Often Mimic Common Eye Conditions
Because TED symptoms overlap with common ocular problems, it can confuse even experienced eye care providers who may initially attribute them to other diagnoses, especially if they do not immediately consider the thyroid connection. For example:
- Eye redness and irritation may be labeled as conjunctivitis
- Dry, gritty eyes may be diagnosed as dry eye syndrome
- Puffiness and irritation may be classified as allergies
- Pain behind the eye is also a common symptom of sinusitis
This tendency to pivot to a less severe diagnosis is well documented and clinical reviews highlight that “early in the active phase, symptoms are commonly misattributed to dry eye disease, conjunctivitis, or allergic eye disease,” and that a lack of specialist awareness contributes to delayed TED diagnosis.
Thyroid Lab Tests May Not Always Correlate with TED Symptoms
Many clinicians rely heavily on thyroid blood tests (TSH, T3, T4, antibodies) to evaluate thyroid disease. However, TED can occur even when thyroid hormones are regulated, or euthyroid, or when thyroid function symptoms have not yet emerged. This mismatch between eye symptoms and thyroid labs can lead providers to believe that the patient’s eye problems are unrelated to thyroid disease, especially if thyroid dysfunction has not been confirmed.
Lack of Awareness Among Non-Specialists
Many patients are initially seen by general practitioners, primary care doctors, or even general ophthalmologists who are not specifically trained or experienced in detecting orbital diseases. Without specific training in thyroid eye disease diagnosis, TED may not be recognized early. As one clinical report notes, TED is “believed to be one of the most common autoimmune disorders in the world,” yet remains commonly unrecognized and/or misdiagnosed, especially outside of thyroid or orbital subspecialty care. Misdiagnosis is more likely when clinicians:
- Do not assess thyroid history
- Do not measure proptosis or eyelid changes
- Do not assess eye movement or early motility restrictions
- Ignore other subtle signs like eyelid retraction, chronic irritation, or periorbital swelling
Proper assessment requires a detailed history, careful physical exam, and often imaging tests that non-specialists may be less likely to perform.
TED Can Occur Before, During or After Thyroid Changes
Another complicating factor is that TED can occur during or after the onset of thyroid disease. While TED is most common in Graves’ disease, it can also occur in Hashimoto’s thyroiditis or in people with normal thyroid hormone levels. This makes the timing of TED diagnosis unpredictable and can lead both patients and clinicians to overlook TED when eye symptoms do not align with known thyroid disease.
TED Progression is Often Non-Linear
TED typically manifests as an active inflammatory phase that plateaus and then develops into a more chronic, possibly fibrotic phase. This timeline can last months or even years, and symptoms often fluctuate. Patients might have flare-ups that improve spontaneously, only to worsen later. This unpredictable course can make it difficult to properly diagnose TED at a specific point in time. If a patient seeks medical attention during a relatively indolent period, the medical practitioner might miss TED.
Early Signs of TED are Subtle and Overlooked
Subtle presentations such as mild eyelid retraction, slight vision asymmetry, or variable double vision can be easily overlooked without careful, eye-specific examination protocols. Research shows that some of the most frequent clinical presentations (dryness, excessive watering, redness) are themselves common complaints in general eye care and are often dismissed as benign dryness or blepharitis (eyelid inflammation). Without specific attention to patterns of muscle restriction and proptosis, or to eyelid position, these early indicators can easily be overlooked.
Other Conditions Can Mimic TED
Even when TED is suspected, there are other rare but important mimics that can complicate its diagnosis. For instance, ocular myasthenia gravis, an autoimmune disorder affecting neuromuscular transmission, can coexist with TED and mask or modify symptoms such as diplopia. Identifying these correctly often requires special testing (e.g., acetylcholine receptor antibodies, EMG) and a high index of suspicion.
Misleading Labels and Terminology Can Confuse Patients and Clinicians
Terms like “Graves’ ophthalmopathy,” “orbitopathy,” or “thyroid-associated orbitopathy” can lead to confusion. Many people (including clinicians) conflate TED with Graves’ disease, failing to recognize that TED is an immune-mediated orbital process that can also occur in people with controlled thyroid disease. This can lead to diagnostic shortcuts based on nomenclature rather than clinical evidence.
Delayed or Missed Diagnosis Impacts Outcomes
Misdiagnosis is not just a semantic problem and has real consequences. Early diagnosis of TED is important because:
- Medical interventions (like steroids, biologics such as teprotumumab) are most effective in the early, active stage
- Delayed diagnosis can lead to irreversible muscle fibrosis, eyelid retraction, and even optic nerve compromise
- Misdiagnosing TED as simple “dry eye” or “allergies” can result in inappropriate treatments that fail to constrain inflammation
Clinical experts emphasize that delayed recognition often causes patients to “miss the window when medical management of the disease can prevent long lasting changes,” increasing the risk of severe disfigurement, vision loss, or more invasive surgical needs later.
How Clinicians Can Improve TED Diagnosis
1. Thorough History of the Patient
It is important to inquire about thyroid disease history, autoimmune conditions, smoking habits (a known risk factor), and subtle eye complaints such as intermittent double vision or unusual dryness.
2. Careful Examination of Eye Movements and Structure
Measuring eyelid position, assessment for proptosis, motility, early eyelid lag evaluation, and imaging if suspicion is high should be considered.
3. Not Relying Solely on Thyroid Labs
As TED can occur even with normal thyroid hormones, antibody levels and clinical signs must guide suspicion.
4. Multidisciplinary Care
Collaboration with endocrinologists, oculoplastic specialists, and orbital disease experts to pool clinical insight and diagnostic resources is essential for a holistic, timely diagnosis of TED
5. Educate Patients
Patients with thyroid disease must be encouraged to report subtle eye symptoms early, as early evaluation can lead to better outcomes.
Concerned About Your Symptoms? Expert Help Is Available
Thyroid eye disease diagnosis is indeed a challenging field not because it is rare, but because its presentation is nebulous, overlaps with common conditions, and does not always correlate with thyroid function. Misdiagnosis stems from overlapping symptoms with dry eye, allergies, conjunctivitis, muscle disorders, and other orbital diseases, as well as inconsistent awareness among generalists. But with proper education, careful clinical evaluation, and multidisciplinary collaboration, providers can significantly reduce missed or delayed diagnoses.
If you are suffering from symptoms of TED and are concerned about treatment options, do not hesitate to schedule an appointment with Dr. Raymond Douglas.
References
- Shah, S. S. & Patel, B. C. in StatPearls (2025).
- Johnson, B. T., Jameyfield, E. & Aakalu, V. K. Optic neuropathy and diplopia from thyroid eye disease: update on pathophysiology and treatment. Curr Opin Neurol 34, 116-121 (2021). https://doi.org/10.1097/WCO.0000000000000894
- Smith, T. J.et al. How patients experience thyroid eye disease. Front Endocrinol (Lausanne)14, 1283374 (2023). https://doi.org/10.3389/fendo.2023.1283374
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