Ocular neuropathic pain

Abstract

As the biological alarm of impending or actual tissue damage, pain is essential for our survival. However, when it is initiated and/or sustained by dysfunctional elements in the nociceptive system, it is itself a disease known as neuropathic pain. While the critical nociceptive system provides a number of protective functions, it is unique in its central role of monitoring, preserving and restoring the optical tear film in the face of evaporative attrition without which our vision would be non-functional. Meeting this existential need resulted in the evolution of the highly complex, powerful and sensitive dry eye alarm system integrated in the peripheral and central trigeminal sensory network. The clinical consequences of corneal damage to these nociceptive pathways are determined by the type and location of its pathological elements and can range from the spectrum known as dry eye disease to the centalised oculofacial neuropathic pain syndrome characterised by a striking disparity between the high intensity of symptoms and paucity of external signs. These changes parallel those observed in somatic neuropathic pain. When seen through the neuroscience lens, diseases responsible for inadequately explained chronic eye pain (including those described as dry eye) can take on new meanings that may clarify long-standing enigmas and point to new approaches for developing preventive, symptomatic and disease-modifying interventions for these currently refractory disorders.

Bowman Break and Subbasal Nerve Plexus Changes in a Patient With Dry Eye Presenting With Chronic Ocular Pain and Vitamin D Deficiency

“…5 It is therefore necessary to understand and predict the severity of symptoms and response to conventional therapy. IVCM has demonstrated increased tortuosity and beading of nerves with variable nerve fiber density in these patients.…”

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

“…Les patients souffrant de douleur oculaire se plaignent également d'une sensibilité accrue à la lumière (ou photoallodynie) [36]. Il est nécessaire de distinguer la douleur oculaire physiologique nociceptive de la douleur oculaire neuropathique [3,37]. En effet, la prise en 6 Filaments de nylon d'égale longueur, mais variant en diamètre, qui permettent d'appliquer sur la zone de choix, à la main, une force reproductible.…”

Relationship of Corneal Pain Sensitivity With Dry Eye Symptoms in Dry Eye With Short Tear Break-Up Time

“…In fact, several reports show a discrepancy between subjectively reported DE symptoms and objectively measured clinical signs. [8][9][10][11] What, in addition to tear stability, causes the provocation of DE symptoms in short-BUT DE?Rosenthal et al 12,13 described the concept of the corneal pain system in the context of neuropathic pain associated with DE disease. We hypothesized that DE symptoms might be provoked in cases featuring alteration of corneal sensitivity in addition to tear instability.…”