From pathogenic considerations to a simplified decision-making schema in dry eye disease.

The modern definition of Dry Eye Disease (DED) combines objective findings, subjective symptoms and mechanistic considerations, among which hyperosmolarity and inflammation play a key role. Historically, DED were classified as due to either insufficient production or impaired stability of tears. There is now evidence that such a dichotomous classification does not fit with the reality of clinical practice, since any abnormality of the ocular surface can trigger disequilibrium in all the other components of tear dynamics. This results in a vicious circle with as many ways to enter as there are causes of destabilization of the ocular surface. Eventually, the patient develops a self-sustaining, and finally severe, DED. Based on these data, we propose a simplified decision-making schema with the goal of assisting ophthalmologists in daily practice in choosing the first line treatment for dry eye disease, and then, if necessary, adapting treatment for the long-term.