Efficacy of automatic pupillometry as a screening technique to detect autonomic dysfunction in bipolar disorder

Autonomic nervous system abnormalities in the pathophysiology of bipolar disorder are controversial. Pupillary features may be affected as a result of autonomic nervous system abnormalities in bipolar disorder. Small changes in pupillary responses may not be noticeable on clinical examination. Automated pupillemetries can be helpful in demonstrating these changes reliably and quantitatively.

The aim of this study was to compare the static and dynamic pupillary responses of bipolar patients with healthy controls. In addition, pupillary response differences between mania, depression and remission stages were investigated.

The bipolar patient group consisted of 39 eyes of 39 patients with 13 patients in each of the stages: mania, depression and remission. The control group consisted of 39 eyes of 39 healthy volunteers. After the ophthalmic examination, static and dynamic pupillometry measurements were made. The mean pupil dilatation speed was calculated according to dynamic measurements. Static pupillometry measurements including scotopic, mesopic and photopic pupil diameters; the first dynamic measurements at 0th second and pupillary dilatation speed were used for statistical analysis.

There was no difference static and the first dynamic pupillometry measurements between the bipolar and control groups (p > 0.05 for all parameters), but there was a significant difference in mean pupil dilatation speed (p = 0.041). No significant differences were found between the 3 groups for all static and the first dynamic pupillometry measurements and the mean pupil dilatation speed (p > 0.05).

Static and the first dynamic measurements of bipolar patients were not different from healthy controls. The mean pupil dilatation speed of bipolar patients was significantly lower, but this difference had a low effect size.