Eye Pain: Etiology and Therapeutic Approaches

The eye is heavily innervated by sensory nerve fibers and inflammatory, ischemic and even neoplastic involvement of the eye and orbit can produce pain. Ocular pain involves the surface of the eye, and orbital pain is felt within the eye. Eye pain can be further differentiated in nociceptive or neuropathic. Nociceptive pain is induced by noxious stimuli, which can trigger nociceptors to fire and cause a painful sensation. Perturbations of the eye surface such as dry-eye, pterygia or conjunctivochalasis, inflammation and infections may be triggers of eye pain. This kind of pain is typically treated by topical antinflammatory agents, ointments, or anesthetics. When eye pain is reported out of proportion to clinical signs, or with no apparent previous insult, neuropathic pain is suspected. In fact, neuropathic pain is not a reaction to noxious stimuli, rather a result from an insult to the nervous system. To complicate matters, the severity of eye pain, that can be unilateral or bilateral, does not indicate how serious the underlying cause of the discomfort is. To date, there is insufficient understanding and no efficient treatment of neuropathic eye pain. The challenge is a better definition of the molecular targets of neuropathic eye pain, and the identification of specific therapeutic agents to be given either as topical or as systemic treatment.

Given the relatively high frequency of eye pain, the multiplicity of its causes (at least 22 possible causes have been described), and the complexity of neuropathic pain, the aim of this Research Topic is to collect a series of contributions addressing its different molecular etiologies and the specific diagnostic and therapeutic approaches. Emphasis will be given to research on neuropathic eye pain, the mechanisms of which are only partially understood. Our overall aim is to collect contributions which can be used to improve approaches and understanding of neuropathic eye pain, so that this Research Topic could stand as a reference guide for all those scientists and physicians who are dealing with the different aspects of eye pain.

We welcome all article types, including clinical studies, to this Research Topic. The themes that we want to cover within this collection are:
1. Epidemiology of eye pain. Different causes and geographic distribution of nociceptive and neuropathic eye pain;
2. Differential diagnostics of eye pain. The characteristics of nociceptive and neuropathic eye pain;
3. The etiology and treatment of nociceptive eye pain;
4. The etiology and treatment of neuropathic eye pain;
5. The use of analgesics and anesthetics in the treatment of severe eye pain;
6. Novel, experimental drugs for eye pain.

Topic Editor Dario Rusciano is employed by Sooft Italia SpA. Topic Editor Anat Galor recently received financial support from Regeneron. All other Topic Editors declare no competing interests with regards to the Research Topic subject.