Methodological concerns limiting the detection of treatment effects in the OSAN trial of blue-blocking glasses for...

This correspondence is a commentary to the recently published report from the OSAN trial by Fiedorowicz et al. but with applicability to the broader research involving blue-blocking glasses and patients in a manic episode.

Clinical studies on dark therapy are still rare, and we read with great interest the report from the OSAN trial published in Journal of Affective Disorders the 1st of April 2026.

The sample was significantly higher in manic symptoms, more medicated and less adherent to the intervention than in preceding studies on effects of dark therapy for mania. Efforts to comply with the gold standard of blinding of raters may have come with the cost of underestimating the symptom level. Extended intervention period (2 weeks) may have caused the extensive loss to follow up (35/42 (83%) at 2 weeks). Several issues with the statistical methods and data reporting make the results difficult to interpret.

The statistical power of the OSAN trial may have been substantially reduced by attrition and multiple sources of variance to the data. The results from the trial should be interpreted with caution.