Pupillometry changes following ocular administration of brimonidine in patients experiencing acute migraine attack

This study aimed to assess pupillometry changes and alterations in clinical headache severity following brimonidine tartrate 0.15% administration in patients with acute migraine attacks.

A randomized controlled prospective study was conducted involving 42 patients with acute migraine attacks and 48 healthy individuals in the control group. Infrared pupillometry and Visual Analog Scale measurements were assessed before and after ocular instillation of brimonidine tartrate 0.15%.

In patients with acute migraine attacks, the mean latency was 156 ms compared with 173 ms in the control group (P = .042). Pupillary amplitude was 2.45 mm in the acute migraine group and 2.91 mm in the control group (P = .041). Both groups exhibited a statistically significant decrease in pupillary diameter after the administration of brimonidine tartrate 0.15% in dynamic and static pupillometry. However, latency was significantly prolonged in the acute migraine group (P = .009), whereas no significant change was observed in the control group (P > .05). Although there was a statistically significant decrease in the anterior chamber depth in the migraine group after brimonidine tartrate 0.15% (P = .005), the decrease in the control group was not significant (P = .052). Visual Analog Scale scores significantly decreased in patients with acute migraine patients after brimonidine (P < .001).

The study findings suggest that patients experiencing acute migraine attacks demonstrate shorter pupillary constriction latencies, indicating the presence of accompanying sympathetic hypoactivity in migraine patients. Latency prolongation after brimonidine suggests sympathetic hyperfunction secondary to chronic sympathetic hypofunction in migraine patients. Brimonidine, with its ability to cross the blood-brain barrier, may provide pain relief through a mechanism similar to that of latency prolongation. This study sheds light on the potential role of brimonidine tartrate in the management of acute migraine attacks, and highlights its effects on pupillometric parameters, thereby contributing to our understanding of migraine pathophysiology and potential treatment avenues.