Important concepts for treating ocular surface and tear disorders

PURPOSE: To outline important concepts for treating ocular surface and tear disorders. METHOD: A review was conducted of recently published findings. RESULTS: Five concepts were delineated: ocular surface health is ensured by a close relationship between ocular surface epithelia and the preocular tear film; a stable rear film is inherently maintained by external adnexae; the intact protective mechanism is controlled by effective neuroanatomic integration; corneal epithelial stem cells are located at the corneoscleral limbus; and ocular surface epithelial cell function is supported by stromal fibroblasts and matrix. CONCLUSIONS: These concepts stress that ocular surface epithelia and the preocular tear film function as a unit and, furthermore, that several corneal and external diseases can be categorized as ocular surface and tear disorders. These concepts also help one formulate unified diagnostic and therapeutic strategies for management of these diseases.