Why a One-Way Ticket to Mars May Result in One-Way Directional Glymphatic Flow to the Eye: Response. Issue 4 (December 2017) - Mader, Thomas H.; Gibson, C. Robert; Otto, Christian A.; Sargsyan, Ashot E.; Miller, Neil R.; Subramanian, Prem S.; Hart, Stephen F.; Lipsky, William; Patel, Nimesh B.; Lee, Andrew G.