Purchase this article with an account.
P. Rosenthal, J. Bradley; Co Morbid Pain in the Innervation Territories of the Non-Ophthalmic Branches of the Trigeminal Nerve Triggered by Corneal Neuropathic Pain Can Be Mitigated by Modulators of Corneal Nociceptor Na+ Channel Function. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3404.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To report the existence of cornea-centric trigeminal neuropathic pain syndrome.
In this retrospective case series, 26 patients with corneal neuropathic pain referred for scleral lens fitting during the period 11/01/08-10/30/09 who failed to experience sufficient benefit wearing the Boston Ocular Surface Prosthesis (BOS-P) were identified. Of these, 10 patients reported collateral head, orbital, facial and temporomandibular pain. After informed consent for off-label drug use, their corneas were treated with subanesthetic concentrations of an amide Na+ channel blocker (lidocaine or ropivacaine) or lacosamide, a non-anesthetic Na+ channel modulator. Either drug was delivered in the fluid reservoir of the BOS-P. Patients were closely monitored by slit lamp biomicroscopy, HRT-II laser confocal microscopy, and Cochet-Bonnet esthesiometry. Pain metrics prior to and during treatment were recorded.
Patient mean age was 49.2±11.1 yrs (2 male, 7 female). Mean average eye pain score prior to treatment was moderate to severe and ranged from mild to excruciating. No metric was applied to co morbid pain prior to treatment. The commonest co morbid pain symptom was migrainous type headaches. Treatment of the cornea with either subanesthetic concentrations of a Na+ channel blocker or a non-anesthetic Na+ channel modulator relieved symptoms of corneal pain/photophobia and collateral pain involving the head, orbit, face and/or jaw in 6 (60%) patients. 1 (10%) of these 6 patients reported only temporary relief and 4 (40%) patients did not experience any relief during treatment. Average treatment time for patients experiencing relief was 5.2±2.7 months.
Downregulating the activity of the pathologically sensitized corneal nociceptors by sodium channel blockade or modulation can be effective in mitigating symptoms of corneal and collateral neuropathic pain in some patients. Failure of this topical treatment may indicate dysfunctional nociceptive activity in the more central corneal pain signaling pathway and may require concomitant use of systemic analgesic therapy.
This PDF is available to Subscribers Only