Dry eye-induced chronic pain involves hypersensitivity and hyperalgesia, and is a clinically serious problem. However, effective therapeutic approach has not been established other than eye drops to alleviate the symptoms. Aiming at developing a pathogenic mechanism-based therapeutic strategy, we performed experiments using a rat dry eye model with lacrimal gland excision (LGE). On the LGE side, corneal hypersensitivity and hyperalgesia were developed. In the trigeminal nucleus of the LGE side, neuronal hyper-activation, transient activation of microglia, persistent activation of astrocytes, upregulation of the voltage-dependent Ca²⁺ channel α₂δ-1 subunit were observed. Next, we evaluated the efficacy of ophthalmic treatment for corneal damage and pregabalin, a ligand for α₂δ-1 subunit, after chronic pain was established in LGE rats. Ophthalmic treatment alone was not effective for hyperalgesia. In contrast, the combination of ophthalmic treatment and pregabalin effectively abrogated hyperalgesia, neural activity, the upregulated α₂δ-1 subunit, and activated astrocytes. These results highlight a crucial role of α₂δ-1 subunit upregulation in the trigeminal nucleus as a pathogenic mechanism and the therapeutic target for dry eye–induced chronic pain.