Peripapillary retinal nerve fiber layer thickness in bipolar disorder.

Background: To compare peripapillary retinal nerve fiber layer thickness (RNFLT) between patients with bipolar disorder and a control group by optical coherence tomography (OCT).

Methods: This prospective comparative case series included 60 eyes of 30 patients with bipolar disorder and 60 eyes of 30 age-matched healthy control subjects. Using OCT, peripapillary RNFLT of the 4 quadrants and the mean of them was compared between the two groups. Variables such as age of onset, duration, smoking, psychosis, mania and depression episodes in the case group and their relationships with RNFLT were evaluated by OCT.

Results: Mean RNFLT was 99 ± 8 in the case group, significantly less than the 106 ± 8 mμ in the control group (p = 0.001). The inferior, superior, and nasal quadrants in the case and control groups showed significant difference in RNFLT (p < 0.001) (p = 0.040) (p = 0.005); however, the temporal quadrant was not reduced significantly, compared to the control value (p = 0.907). Moreover, the only variable showing significant relation with RNFLT was duration of bipolar disorder (p = 0.040).

Conclusion: Reduction of peripapilary RNFLT occurs in patients with bipolar disorder, and is related to the duration of disease. RNFLT can be a beneficial value for studying neurodegenerative changes over time towards detecting the severity and duration of disorder.