Severe Neuropathic eye / Ocular Pain and the Role of the Autonomic Nervous System and Sphenopalatine Ganglion Blocks in Diagnosis and Therapeutic Treatments. The diagnosis of neuropathic ocular pain is typically a diagnosis of exclusion. This means that there is no clear diagnostic signs and symptoms. Altered response and perception of pain to non-painful stimuli is called Allodynia and ocular …