Pathophysiology of dry eye disease and novel therapeutic targets

The pathophysiology of Dry Eye Disease (DED) is complex, and therapy may be a challenge. Tear film instability, tear film hyperosmolarity, ocular surface damage and ocular surface inflammation are accepted key events in the pathogenesis of the disease. New anti-inflammatory targets have been identified and novel anti-inflammatory treatments may enrich our therapeutic armamentarium in the future. Neurosensory changes in DED secondary to neuroinflammation in the corneal nerves, the trigeminal ganglion, and the trigeminal brainstem sensitivity complex have recently been reported and may play an important role in the pathophysiology of DED. Receptor complexes on the axonal membranes of corneal nerves may be promising novel therapeutic targets. Recent studies have shown changes in the both the systemic and local (conjunctival) microbiomes with DED as well as an association of DED with laryngopharyngeal reflux. These new insights into DED suggest new treatment approaches. In hyperevaporative DED typically associated with meibomian gland dysfunction (MGD), hyperkeratinized and obstructed meibomian glands are important treatment targets, and novel techniques may be available soon to better manage patients with MGD. The observation of changes in brain function in patients with DED sheds a completely new light on the pathophysiology of the disease. Increased understanding of the pathogenetic events described above may define novel treatment targets, guide management and may allow customized treatment of DED in the future. Pathophysiological events in Dry Eye Disease (DED) targeted by new treatment options include:•Ocular surface inflammation•Changes in the conjunctival/intestinal microbiota and the association of DED with laryngopharyngeal reflux•Neurosensory changes and neuroinflammation•Hyperkeratinized and obstructed meibomian glands