Understanding the true burden of dry eye disease.

The term "dry eye" has evolved over the past 2 decades to include both symptoms (visual complaints and dysesthesias) and signs (aqueous and evaporative deficiency) of disease. Dry eye is common in older individuals and a source of morbidity. Confusion arises, however, on what combination of symptoms and signs constitute "dry eye" and how to best individualize treatment in patients. This editorial will discuss the evolution of dry eye, discuss potential sub-categorizations for the disease, and discuss their potential implications on treatment.