Focused Narrative Review: Non-Pharmacological, Noninvasive Neurostimulation or Neuromodulation Treatment of Ocular Neuropathic Pain.

Ocular neuropathic pain is typically treated with local anti-inflammatory and neuroregenerative agents, and psychological approaches such as cognitive behavioral treatment, as well as systemic pharmacological medications and nerve blocks. In recalcitrant cases, neurostimulation or neuromodulation may be considered. In this review, we evaluate the existing literature for the use of non-invasive forms of neurostimulation: home-based extra nasal neurostimulation (iTear100), extracranial direct current stimulation (tDCs), transcutaneous electrical nerve stimulation (TENs) and transcranial magnetic stimulation therapy (TMS). We compared the mechanism of action of these therapies and clinical studies of their effectiveness. Although most of the published literature is based on general neuropathic pain and often combinatorial treatment, we compared the pros and cons of using such modalities for ocular neuropathic pain, including effectiveness, potential side effects, convenience and other factors.