MUC5AC and rheumatoid arthritis: Another important point to keep in mind is how RA-related dry eye includes both aqueous-deficient and evaporative types of DED, affecting the conjunctiva and meibomian glands. Usuba et al. demonstrated the evaporative component disturbance in RA patients, with the presence of MGD (associated with alterations in the lipid layer of tear film) as well as decreased goblet cell numbers (associated with the mucin layer of the tear film), in addition to the traditional aqueous tear deficiency related to DED [16].