Neuropathic ocular pain: What is it and what to do about it?

Abstract

Ocular surface pain (OSP) is a nonspecific symptom that can have a tremendous impact on quality of life. Individuals use various descriptors to characterize OSP including “dryness”, “burning”, “grittiness”,” shooting”, “discomfort”, “tenderness” and/or “aching”, to name a few. As feeling your eyes is “an unpleasant sensory and emotional experience”, these descriptors fit under the International Association for the Study of Pain (IASP) definition of pain.” Oftentimes, OSP is chronic in nature, lasting >3 months, although the intensity of pain can wax and wane over time. Furthermore, OSP can occur spontaneously or be triggered by stimuli such as light, wind or temperature change. In the past, OSP was placed under the umbrella term “dry eye”, as tear film abnormalities are one cause of OSP. However, it is now understood that factors beyond tear and ocular surface abnormalities may drive OSP and it is necessary to identify and address all potential contributors to pain. In general, contributors can be split across two broad categories: nociceptive contributors, defined as pain that arises directly from tissue damage at the level of the ocular surface and neuropathic contributors, defined as pain caused by a lesion or disease within peripheral or central nerves that connect the ocular surface to the brain. Or, as is the case in many individuals, pain contributors can arise from a combination of these two entities. Given the multiple potential contributors to OSP, a standardized examination and multimodal approach is necessary. In this presentation, we discuss advances in the diagnosis and management of OSP, with a focus on the diagnosis and treatment of neuropathic ocular surface pain (NOP).