Nerve blocks used to treat peripheral neuropathic pain elsewhere in the body can successfully treat chronic ocular pain from a variety of causes.
Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage, according to the International Association for the Study of Pain.
Patients with chronic ocular pain may benefit from the use of nerve blocks that generally are used to treat peripheral neuropathic pain elsewhere in the body.
Pain disorders can be nociceptive, that is, characterized by pain that arises from actual or threatened damage to non-neural tissue, such as with severe ocular surface disease, band keratopathy, and intraocular inflammation, or they can be neuropathic, as with pain resulting from damage to or changes occurring in the nervous system, such as that caused by a previous cataract, LASIK, or RK surgery; neuralgia associated with the herpes virus; and eye drops containing the preservative benzalkonium chloride, noted Ann Quan, MD.
Neuropathic pain is a complex process resulting from various receptors, she continued. The corneal nociceptors are comprised of polymodal nociceptors that sense chemical, thermal, and endogenous inflammatory mediators, mechanoreceptors that sense mechanical stimuli, and cold thermoreceptors that sense evaporation.
The terminal nerve endings of the corneal nociceptors interact with the external environment and by doing so, they are susceptible to damage during inflammation or repetitive environmental injuries.
The nociceptive causes of ocular pain, i.e., inflammation, tear dysfunction, and anatomic abnormalities are commonly treated; however, the pain often persists, suggesting there can be a neuropathic component.
Drs. Quan and colleagues retrospectively reviewed the medical records of patients in the Oculofacial Pain Clinic, University of Miami, from Jan. 1, 2017 to Aug. 11, 2018, to determine if use of nerve blocks can effectively treat chronic ocular pain that likely has neuropathic components.
Ann V. Quan, MD
Dr. Quan has no financial interest in any aspect of this report.