Causes of Rheumatoid Arthritis of the Eye (RAE)
Rheumatoid arthritis of the eye is caused by autoimmune-mediated inflammation that extends from systemic rheumatoid arthritis to ocular tissues, resulting in inflammatory eye diseases including keratoconjunctivitis sicca, episcleritis, scleritis, and peripheral ulcerative keratitis. 1
Primary Pathophysiologic Mechanism
The ocular manifestations of rheumatoid arthritis represent extra-articular complications of the systemic autoimmune disease, where the same inflammatory processes affecting joints extend to ocular structures. 1, 2
- Autoimmune-mediated tissue damage on the ocular surface occurs through defects in innate immunity, including Toll-like receptors, S100A proteins, and resident antigen-presenting cells. 3
- Cytokines, chemokines, and T helper cell subsets (particularly TH1 and TH17) drive the inflammatory cascade that damages ocular tissues. 3
- Systemic vasculitis associated with RA can lead to the most severe ocular complications, including necrotizing scleritis and peripheral ulcerative keratitis, which are associated with excess mortality. 1
Specific Ocular Conditions and Their Causes
Keratoconjunctivitis Sicca (Dry Eye)
- Most common ocular manifestation of RA, occurring more frequently and with greater clinical severity than idiopathic dry eye. 4, 3
- Caused by autoimmune destruction of lacrimal gland tissue and inflammatory disruption of tear film production. 3
Episcleritis and Scleritis
- Episcleritis affects approximately 5% of RA patients and represents inflammatory involvement of superficial episcleral vessels. 4
- Scleritis occurs in approximately 2% of RA patients, with RA being the leading cause of necrotizing scleritis. 1, 4
- Nodular scleritis results from inflammatory nodule formation within scleral tissue. 4
Peripheral Ulcerative Keratitis (PUK)
- RA is the leading cause of PUK, representing one of the two most severe ocular conditions associated with the disease. 1
- Caused by inflammatory destruction of peripheral corneal stroma adjacent to sites of inflammation, often associated with systemic vasculitis. 4
Retinal Vasculitis
- Occurs in approximately 0.45% of RA patients and represents inflammatory involvement of retinal blood vessels. 4
- Associated with systemic vasculitic manifestations of RA. 4
Important Clinical Context
The ocular inflammation can occur at a different time from articular disease, meaning eye involvement may precede, coincide with, or follow joint symptoms. 3 This is critical because:
- Ocular manifestations can be the first signs of rheumatoid arthritis in some patients. 1
- The severity of ocular involvement does not always correlate with the severity of joint disease. 3
- Necrotizing scleritis and PUK rapidly threaten ocular prognosis and require urgent recognition and treatment. 1
Key Pitfall to Avoid
Do not assume that well-controlled joint disease means the eyes are protected—ocular surface immune factors can be influenced by the systemic immune landscape but may require independent monitoring and treatment. 3 Close collaboration between ophthalmology and rheumatology is essential for diagnosis and management. 1, 2