Primary Sjögren's syndrome is a chronic autoimmune disease that primarily involves exocrine glands, most commonly manifested in dry eye, dry mouth, and in other systems of the body.

Patients usually first seek for the ophthalmologist for severe dry eye symptoms, and most clinicians are ill-informed about Sjögren's syndrome dry eye disease (SS-DED), which can lead to missed diagnoses and misdiagnoses. Clinically, there are not many types of patients with pSS and the number of in-depth studies is small. Meanwhile, there are no specific drugs for the treatment of SS-DED, and most patients need to be treated with multiple methods to understand which methods are most effective. In this study, by establishing a clinical cohort of patients with different subtypes of dry eye with pSS, we explored the association between the primary organs affected by pSS and various biomarkers related to tear fluid and blood, and the association between the primary organs affected by pSS, tear components and blood markers and the severity of ocular involvement, symptom progression and prognosis. This study initially constructs a special cohort of patients with pSS ocular involvement, which may explain its pathogenesis from a new perspective in diagnose, classification and treatment.

Inclusion Criteria:

• All enrolled DED participants met the criterion of TFOS DEWS II Definition and Classification Report and pSS-DED group also met 2016ACR/EULAR pSS diagnosis and classification consensus.

Exclusion Criteria:

• (1) patients were diagnosed as any rheumatic or systematic diseases that would probably affect tear function except for pSS and DED. (2) had a history of ocular trauma or surgery. (3) had a history of wearing contact lens. (4) had concomitant ocular lesions such as acute inflammation or infection, glaucoma or eyelid abnormalities. (5) cannot cooperate properly or finish related examinations.

pSS and DED patients who visited the dry eye clinic of Peking University Third Hospital from January 2021 to January 2028.