Thank you for this innovative and important work! The article is very well structured and conducted.

To the limitations and as a proposal for the pilot study, I suggest using a short, potentially visual subjective patient report about feasibility. Objective measurement of circadian rhythm with an actigraph including pre-post-intervention would enormously improve scientific impact of the pilot, now lack of any report of individual rhythms is a limitation. Manic symptoms, insomnia and irritation of eyes would seem be the most likely adverse effects of the therapy and as such, adverse effects could be measured separately. Conversely, lack of reporting adverse effects is a limitation to be discussed.

As an ethical question: were the participants allowed to leave the room, and for how long?

MMSE is a very robust measure for cognition; limitations could be mentioned in the discussion and importance of this association maybe seen a little more critically?

Why did you choose stable participants? What do you expect to see in acute patients, would this illumination be feasible for them?

I hope to see the pilot study any time soon!

Thank you for addressing the comments. Referring to feedback in the discussion is exceptional; listing the limitations independent whether they were raised by the team or referees is sufficient.