Clinical Outcomes of Fixed Versus As-Needed Use of Artificial Tears in Dry Eye Disease: A 6-Week, Observer-Masked Phase 4 Clinical Trial

To evaluate the clinical effects of using fixed (four times daily [QID]) versus as-needed (PRN) dosing of an artificial tear product (polyethylene glycol/propylene glycol [PEG/PG]; Systane Ultra) in individuals with dry eye disease. In this prospective, multicenter, observer-masked, active-control, parallel-group trial, participants were randomized (1:2 allocation) to receive 1 drop of PEG/PG QID (n = 34) or PRN (n = 63) for 28 days. The primary endpoint was change from baseline in the total ocular surface staining (TOSS) score (according to the Oxford scale) at day 28. At day 28, the change from baseline in least squares mean (LSM) TOSS scores for QID and PRN groups were -1.19 and -0.94, respectively (treatment difference [TD]: -0.26; 95% confidence interval [CI]: -∞ to 0.21; P = 0.184); superiority of QID versus PRN dosing was not established, as the upper limit of one-sided 95% CI for TD was not