Hashimoto’s disease is strongly correlated with an increased risk of developing dry eye syndrome, formally known as Keratoconjunctivitis sicca. Hashimoto’s is an autoimmune disorder where the immune system attacks the thyroid gland, causing chronic inflammation and typically resulting in hypothyroidism. This systemic autoimmune activity extends beyond the thyroid, affecting other moisture-producing glands, including those responsible for tear film production. The connection lies in the shared immune response, making dry eye a frequent extra-thyroidal manifestation of the disease.
The Confirmed Link Between Thyroid Disease and Ocular Health
The thyroid gland regulates metabolism, and its hormones influence many bodily functions, including those related to the ocular surface. When the thyroid is attacked in Hashimoto’s, the resulting systemic inflammation impacts multiple tissues, making the eyes vulnerable. This inflammation can destabilize the tear film, the delicate coating that protects the eye’s surface. Dry eye symptoms can occur even when thyroid hormone levels are controlled with medication.
The connection relates more to the overall autoimmune status of the body than to specific thyroid hormone levels. Autoimmune processes can target the lacrimal glands, which produce the watery part of tears, leading to impaired tear production. This systemic link means that managing the thyroid condition alone may not resolve the associated eye problems. Studies show that Hashimoto’s patients, even without Thyroid-Associated Ophthalmopathy (TAO), have significantly lower tear break-up times and Schirmer test scores, objective measures of tear film quality and quantity.
Autoimmune Mechanism Behind Tear Gland Dysfunction
The mechanism linking Hashimoto’s to dry eyes is primarily the misdirected autoimmune response and chronic inflammation. The immune system generates antibodies and T-cells that attack the thyroid tissue. These same inflammatory cells and cytokines can circulate and infiltrate the lacrimal glands, which produce the aqueous layer of tears. This infiltration disrupts the glands’ function, reducing the volume of tears produced.
The autoimmune process can also target the Meibomian glands in the eyelids, which produce the oily layer of the tear film. Damage to these glands causes Meibomian Gland Dysfunction (MGD), leading to rapid tear evaporation and evaporative dry eye. Research suggests that the duration of Hashimoto’s disease correlates with the severity of Meibomian gland loss. Specific inflammatory markers, such as MMP-9 and IL-6, are elevated in systemic autoimmune diseases and have been found in the tears of Hashimoto’s patients, confirming the inflammatory nature of the damage.
Distinguishing Dry Eyes Caused by Co-occurring Conditions
While Hashimoto’s can directly cause dry eyes through systemic inflammation and glandular dysfunction, it frequently co-occurs with other autoimmune conditions that are primary causes of severe dryness. The most significant is Sjögren’s Syndrome (SS), a systemic autoimmune disorder that specifically attacks moisture-producing exocrine glands. Individuals with Hashimoto’s are at a significantly higher risk of developing Sjögren’s Syndrome compared to the general population.
Sjögren’s Syndrome causes a more profound and widespread form of dryness, affecting the eyes, mouth, and other mucosal surfaces. This clustering of autoimmune diseases suggests a common genetic and immunological vulnerability, often sharing similar immune pathways. Recognizing this distinction is important for diagnosis, as severe dry eye may prompt screening for Sjögren’s Syndrome. Other contributing factors include Vitamin D deficiency, which is common in those with autoimmune thyroid disease and influences immune function.
Treatment Strategies for Chronic Dry Eye Symptoms
Management of dry eyes in the context of autoimmune disease requires a multi-faceted approach that goes beyond simple over-the-counter lubricating drops. The initial step is often the use of preservative-free artificial tears and gels, which provide temporary relief and surface moisture. For patients with chronic inflammation, prescription anti-inflammatory eye drops, such as topical cyclosporine or lifitegrast, are often necessary to suppress the immune response and increase tear production.
If evaporative dry eye due to Meibomian Gland Dysfunction is the primary issue, in-office procedures such as thermal pulsation or Intense Pulsed Light (IPL) therapy can be used to clear clogged glands and restore healthy oil flow. Another option is punctal occlusion, where tiny plugs are inserted into the tear ducts to block drainage and keep natural tears on the eye’s surface longer. Coordinating care between an endocrinologist, who manages the underlying Hashimoto’s disease, and an ophthalmologist, who specializes in ocular surface health, is recommended for comprehensive treatment.