AST Combined With 0.05% Cyclosporin Eye Drop Improve Corneal Nerve Density in Patients With SS Dry Eye

Inclusion Criteria: * Patients were diagnosed with SS according to the classification criteria defined by the American-European Consensus Group for the diagnosis of SS and also diagnosed with severe DED based on the consensus of Chinese dry eye experts. * Age 18-65 years old. * Controlled collagen disease by the same rheumatologists at least 3 months prior to the initiation of the trial. * At least one eye that failed to respond to previous treatments including lartificial tears, topical ocular NSAIDs or corticosteroids. Exclusion Criteria: * Patients with DED related to meibomian gland dysfunction, blepharitis, abnormal blinking, conjunctival relaxation or any other diseases besides SS. * Diagnosed with allergic conjunctivitis, uveitis, ocular hypertension, retinopathy and other eye diseases. * Those who have a history of previous ocular oprations, eye injuries or contact lenses usage. * Known hypersensitivity to experimental drugs or any of its ingredients. * Necessity to modify the systemic treatment of previous diseases during the trial. * Pregnancy or lactation. * Severe systemic disease.