Burning Eye Syndrome: Do Neuropathic Pain Mechanisms Underlie Chronic Dry Eye?

Abstract

Dry eye is becoming a major health concern due to its increasing incidence, significant morbidity, and economic burden. Recent evidence suggests that a subset of dry eye may be better represented as a chronic neuropathic pain disorder due to its features of dysesthesia, spontaneous pain, allodynia, and hyperalgesia. Future therapies targeted at the underlying neuroplasticity may yield improved efficacy for patients with this subset of dry eye, which we term "burning eye syndrome."

Association of dry eye disease with psychiatric or neurological disorders in elderly patients

“…Acute axonal injury during corneal nerve damage facilitates the release of inflammatory mediators, including prostaglandins, cytokines such as interleukin-1 and tumor necrosis factor-α, and neuropeptides such as substance P, which can reduce the threshold potentials of ion channels of corneal nerve endings 56. Subsequent release of nerve growth factor leads to upregulation and expression of genes, resulting in hypersensitivity of corneal nociceptors to stimuli 2,56. In addition, chronic severe or repeated axonal injury promotes the transition of the function of corneal nociceptors from signal transmission to nerve regeneration 2.…”

“…Subsequent release of nerve growth factor leads to upregulation and expression of genes, resulting in hypersensitivity of corneal nociceptors to stimuli 2,56. In addition, chronic severe or repeated axonal injury promotes the transition of the function of corneal nociceptors from signal transmission to nerve regeneration 2. With regeneration, the injured nerve can develop microneuromas, endobulbs and nerve sprouts, which can be sources of spontaneous pain 2,56.…”

“…For neuropathic pain, considering that pain can become spontaneous and unresponsive to artificial tear instillation once central sensitization develops, limitation of the neuroplastic sensitization process by prevention of ocular surface damage and inflammation in the initial stages would be important 2,21,56,82. Aggressive treatment with anti-inflammatory medications is necessary for relief of acute pain and improvement of ocular surface inflammation 56,82.…”

“…It is associated with symptoms including ocular discomfort, pain, dryness and foreign body sensation, which can impair the quality of life of millions of people worldwide 1. In terms of economic burden, DED has become a major public health problem 2. DED poses an average cost of $11,302 per patient and an estimated overall cost of $55.4 billion to the US society annually 3…”

“…Although this discrepancy can partly be explained by the limited reliability of the dry eye tests currently available; individual differences in cognitive response to dry eye questionnaires,9 the heterogeneous nature of DED and individual variability in the perception of dry eye symptoms may also play an important role 9. In particular, studies focused on the association of DED with neurological or psychiatric disorders have suggested the role of neurological or psychological factors in the development of dry eye symptoms, particularly in elderly patients 2,12,17–21. Vehof et al17 recently showed that severe dry eye symptoms unproportional to external signs were associated with lower level of self-perceived health.…”