Modern OptometryTRP’n Out: OSD, Inflammation, and Nerves

Dry eye disease (DED), ocular surface disease (OSD), and other cornea and anterior segment diseases can cause patients to experience a diverse range of symptoms. The cornea is the most densely innervated tissue and is therefore an important target for therapeutics and research. Transient receptor potential (TRP) channels are signaling channels that play roles in signaling physiological processes, and TRP melastatin member 8 (TRPM8) is a cold-sensing receptor found on nerve endings of the ophthalmic branch of the trigeminal nerve. TRPM8 channels sense cooling changes in corneal temperature and are activated by evaporative cooling and hyperosmolarity, leading to stimulation of tear production, which may be why eyes water on cold days and in patients with dry eye. Understanding the interaction between symptoms, ocular healing, and dysfunctions that occur in this process can help optometrists care for their patients more effectively.