Oculosympathetic alterations in migraine patients

Oculosympathetic function was studied in 20 headache-free migraine patients and in 20 controls. Pupillary investigation was performed under basal conditions, and after instillation of tyramine (2%) and phenylephrine (1%) eyedrops. Each test was performed twice shortly after a spontaneous attack and then repeated after 7 and 15 days. In the patients, the normal mydriatic response induced by tyramine was significantly (p<0.001) reduced and phenylephrine instillation caused a significant (p<0.01) pupillary dilatation in both the assessments performed shortly after the attack. These abnormal responses were bilateral in all patients and slightly anisocoric in some. They were significantly (p<0.001) more pronounced in the patients who had pain and pronounced vascular features. The reduced oculosympathetic response to tyramine, as well as the hypersensitivity to phenylephrine, was less evident 7 days after the attack and absent after 15 days. A transient and bilateral post-ganglionic oculosympathetic hypofunction, with adrenoceptor hypersensitivity, was found to be temporally related to the migraine attack, regardless of the side or predominant side of pain.