Early diagnosis can help prevent the more severe ocular manifestations of TED

Thyroid eye disease (TED) is an inflammatory process that can affect multiple contents of the orbit and may mimic several other ocular conditions, such as allergic conjunctivitis, ocular surface disease, orbital inflammatory disease, and more.¹ As discussed previously in this column (see Optometric Management March 2022, bit.ly/OM2203TED ), patients with thyroid disease are likely to develop ocular manifestations in about 30% to 40% of cases.² Remember, having thyroid disease does not automatically mean TED will develop; it is classified as a risk factor.

Due to the complexity of this disease, diagnosing TED can be challenging. To help prevent the more severe ocular manifestations of TED from developing, it is important to diagnose and treat the disease early.

SYMPTOMS

Most TED patients present with bilateral ocular symptoms that are often asymmetric.³ These patients may complain of dry eyes, ocular irritation, itching, redness, tearing, grittiness, diplopia, pain upon eye movement, light sensitivity, pressure, soreness, and/or a decrease in vision.⁴

SIGNS

Eyelid retraction, also known as the “stare” appearance, occurs in 90% of TED patients. Exophthalmos (proptosis) occurs in 60%, followed by restricted eye movements in 40% of patients.⁵ Signs of periorbital swelling can lead to restrictive myopathy, chemosis, conjunctival injection, orbital fat prolapse, proptosis, and optic neuropathy. Other TED signs include lid lag on downgaze. The combination of proptosis and eyelid retraction can exacerbate ocular surface disease symptoms and result in keratopathy.¹

Optic neuropathy and exposure keratopathy are considered ocular emergencies because they can abruptly lead to blindness.¹ Compartment syndrome effect should be considered in patients who have minimal proptosis because they are at a high risk of developing compressive optic neuropathy.³

The inferior rectus muscle is usually affected first, followed by the medial, superior, and lateral rectus, and then the oblique muscles.³ Using grading systems, such as NOSPECS, CAS, EUGOGO, etc. can help document the severity and overall involvement of the disease.¹

TESTING MODALITIES

Ancillary testing can be critical in assessing the level of severity and ocular involvement of TED. VF testing can help determine any generalized constriction, arcuate defects, or enlarged blind spots; however, it may also show random and nonspecific defects. Imaging can help measure orbital inflammation and will often show tendon-sparing enlargement of the extraocular muscles. MRI and CT scans can help determine the level of compressive optic neuropathy. Hertel exophthalmometry can quantify the amount of proptosis. In undiagnosed thyroid disease patients, obtaining a thyroid panel is important to rule out any underlying autoimmune condition.⁶ TED can significantly affect a patient’s quality of life, so it is crucial to rule it out as a differential. OM

The next TED column will appear in the July 2022 issue and address treatments for TED.

REFERENCES

1. McAlinden, Colm. An overview of thyroid eye disease. Eye and Vision (Lon). 2014; 1: 9. doi: 10.1186/s40662-014-0009-8.
2. Bartalena L, Tanda ML. Graves’ ophthalmopathy. N Engl J Med. 2009 Mar 5;360(10):994-1001. doi: 10.1056/NEJMcp0806317.
3. Li, Zhen et al. Thyroid eye disease: what is new to know? Curr Opin Ophthalmol. 2018 Nov;29(6):528-534. doi: 10.1097/ICU.0000000000000529.
4. Denniston AKO, Murray PI: Oxford Handbook of Ophthalmology. Oxford University Press; 2009.
5. Bartley GB, Fatourechi V, Kadrmas EF et al. Clinical features of Graves’ ophthalmopathy in an incidence cohort. Am J Ophthalmol. 1996 Mar;121(3):284-90. doi: 10.1016/s0002-9394(14)70276-4.
6. Kim H, Joon. How to Recognize & Treat Thyroid Eye Disease. Nov 2013. Rev Optom. https://www.reviewofoptometry.com/article/how-to-recognize--treat-thyroid-eye-disease . Accessed March 14, 2022.

Dr. Huegel graduated from the Southern College of Optometry, and is currently completing her residency in ocular disease and anterior segment at Associated Eye Care in Stillwater, Minn.