Neuropathic Ocular Pain: An Important Yet Underevaluated Feature of Dry Eye

A Galor; RC Levitt; ER Felix; ER Martin; CD Sarantopoulos


Eye. 2015;29(3):301-312. 

In This Article

Dry Eye as a Pain Disorder

Pain, as defined by the International Association for the Study of Pain (IASP), is 'an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage'.[27] Based on this definition, some patients with dry eye (depending on their symptoms) have pain. Within the group with pain, some patients have transient pain, whereas others have persistent symptoms and a more chronic disease course (typically defined as symptom duration of >3–6 months).

Pain disorders are broadly grouped into two categories: nociceptive pain and neuropathic pain, and both may be involved in dry eye. Nociceptive pain is usually transient and a result of tissue damage and inflammation.[28] In the case of dry eye, various insults may lead to ocular surface damage including infection, inflammation, trauma, adverse environmental conditions, abnormal ocular anatomy, and high tear osmolarity. Neuropathic pain is defined as 'pain arising as direct consequence of a lesion or disease affecting the somatosensory system' and is more likely to be chronic.[29] In dry eye, the inciting factors for nociceptive and neuropathic pain may be the same but the difference is that these stimuli can lead to transient or persistent changes in the phenotype of sensory neurons.[28]