The cornea and systemic diseases.

Corneal involvement in systemic diseases is multifold. Dry eye syndrome may be associated with autoimmune diseases. Type I diabetes mellitus shows a positive correlation between HbA1c-level and dry eye syndrome. Autoimmune diseases and occasionally malignancies may be associated with ulcerative keratitis. Opportunistic infections do not only occur in the immunocompromised patient. Storage diseases can cause corneal deposits that may be of great diagnostic halp. Dermatologic diseases can cause various corneal lesions or opacifications.