Figure 1: Peripheral and central sensitization under persistent dry eye pain. After the removal of the Harderian gland and extraorbital gland in adult mice, nerve abnormalities, inflammation and sensitization of the corneal nerves developed. These mechanisms trigger the activation of primary sensory neurons, immune and glial cells in the ipsilateral trigeminal ganglion. This peripheral neuroinflammation spreads to the trigeminal brainstem sensory complex, leading to persistent ocular pain. ATF3: Activating transcription factor 3; c-fos: Fos proto-oncogene; IL: interleukin; NOS: nitric oxide synthase.