Dry Eye in Rheumatoid Arthritis
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of unknown etiology that primarily targets synovial tissues. It is the most common inflammatory arthritis, affecting from 0.5% to 1% of the general population worldwide.1 It results from a complex interaction between genes and environment, leading to a breakdown of immune tolerance and synovial inflammation in a characteristic symmetric pattern. The diagnosis of RA can be made in a patient with inflammatory arthritis involving three or more joints, positive rheumatoid factor (RF) and/or anticitrullinated peptide/protein antibody (ACPA), disease duration of >6 weeks, and elevated C reactive protein (CRP) or erythrocyte sedimentation rate (ESR), but without evidence of diseases with similar clinical features.2 Although RA is primarily considered a disease of the joints, it may involve many organs because of abnormal systemic immune responses. Involvement of systemic disease occur in 40% of patients with RA over lifetime.