Abstract
Purpose :
Disease or injury of the peripheral corneal nerves may result in ectopic activity and abnormal excitability, and thus may lead to neuropathic corneal pain (NCP). Conventional treatment for NCP consists of anti-inflammatory agents, neuroregenerative therapies, and ocular surface rehabilitation. Extranasal neurostimulation (EXNS) is a new adjuvant therapy in the treatment of dry eye disease. Given the gate control theory, we hypothesized that the EXNS would decrease abnormal stimulus generated by the nociceptors on the ocular surface. The purpose of this study is thus to evaluate the efficacy of the EXNS to ameliorate peripheral pain among NCP patients.
Methods :
Retrospective, pilot study in 19 NCP patients with peripheral or combined (peripheral and centralized) pain as assessed by the proparacaine challenge test that were tested for EXNS use in the office. Only patients that respond (reducing pain level) to the proparacaine challenge test were included for this study. The visual analogue scale (VAS) (0-10) was used to rate the pain level before and after 30 seconds of EXNS.
Results :
Of the 19 patients included, 15 patients (78.9 %) were female, and the average age was 46.94±15.7 years. The mean score for pain before EXNS was reported as 5.83±1.94 OD and 5.79±2.37 OS. Average pain after 30 seconds of EXNS decreased to 2.61± 2.06 OD and 2.95± 2.32 OS, with a 55.3% and 49.1% reduction in pain after EXNS, respectively (p<0.01, for both eyes). EXNS resulted in complete resolution of pain in 3 (15.8%) patients, 8 (42.2%) patients with 50-99% improvement in pain, 6 (31.5%) patients with 1-49% improvement in pain, and 2 (10.5%) patients with no improvement in pain. Eight patients had true peripheral pain (complete resolution of symptoms after proparacaine test) and experienced 66.5% improvement in pain. The remaining 11 patients demonstrated partial central component of pain (not complete resolution of symptoms after proparacaine challenge) and showed 45.0% improvement in pain.
Conclusions :
EXNS may be used as an adjuvant therapy to ameliorate pain among NCP patients with peripheral pain components. Further prospective and longitudinal studies are warranted to demonstrate the efficacy and duration of effect of EXNS in reducing pain among NCP patients.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.