The placebo has the identical composition as the DP except it does not contain timbetasin acetate. clinical trials

SEER-3: A Phase 3, Multi-Center, Randomized, Parallel, Double Masked, Placebo-Controlled Clinical Study to Assess the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of Neurotrophic Keratopathy

This study is testing a new eye drop (RGN-259) for a condition called Neurotrophic Keratopathy (NK). We want to see if the eye drop helps heal problems on the surface of the eye better than a dummy drop, and if it's safe to use.