Abstract
Purpose :
Purpose: Neuropathic Corneal Pain (NCP) is a chronic pain caused by a lesion or dysfunction of the somatosensory nervous system. Long-term injury to peripheral corneal sensory nerves leads to the development of ectopic activity and abnormal excitability of peripheral nerve terminals causing neuropathic pain. Conventional treatment for peripheral NCP includes neuroregenerative and anti-inflammatory therapy. Intranasal Neurostimulation (ITNS) stimulates the ethmoidal nerve inside the nasal cavity and has been used as a coadjuvant therapy in the treatment of dry eye patients, increasing the quality and quantity of tears. Based on the gate control theory, the stimulation triggered from other myelinated nerve fibers can block the nociceptive input delivered to higher centers, we hypothesized that the use of ITNS would decrease abnormal stimulus generated by the nociceptors on the ocular surface as it occur in non-ocular sites. The purpose of this study is thus to explore the effectiveness of ITNS to ameliorate peripheral pain among NCP patients.
Methods :
Method: Retrospective, pilot study in 37 NCP patients with peripheral or combined (mixed and centralized) pain that were tested for ITNS use in the office. The visual analogue scale (VAS) (0-10) was used to rate the pain level before and after 3 minutes of ITNS. Patients were pre-screened for centralized pain using proparacaine drops. Only patients that respond (reducing pain level) to the proparacaine challenge test were included for this study.
Results :
Results: Of the 37 patients included, 27 (73%) were female, the average age was 48.7±17.6 years. The mean score for pain before ITNS was reported as 5.3±2.3. Average pain after 3 minutes of ITNS decreased to 1.5±1.6, with a 71.7% (p<0.01) reduction in pain after ITNS. Only 1 patient had true peripheral pain (complete resolution of symptoms after proparacaine test) and experienced complete relief of pain (zero in VAS). The remaining of patients (26) demonstrated partial central component of pain (not complete resolution of symptoms after proparacaine challenge) and showed 69.8% improvement in symptoms of pain.
Conclusions :
Conclusion: ITNS may be used as an adjuvant therapy to ameliorate pain among NCP patients with peripheral pain component. Further prospective and longitudinal studies are warranted to demonstrate the efficacy and duration of effect of ITNS in reducing pain among NCP patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.