Study of ST-100 as Treatment for Dry Eye Disease

This is a Phase 2, multi-center, double-masked, randomized, placebo-controlled clinical study. Subjects will be randomized to one of the following treatment arms at Visit 2 (Day 1): * Low dose ST-100 Ophthalmic Solution: 1 drop twice daily (BID) in each eye * High dose ST-100 Ophthalmic Solution: 1 drop BID in each eye * Placebo Ophthalmic Solution (Vehicle): 1 drop BID in each eye Approximately 150 subjects will be randomly assigned to one of the three groups (1:1:1) to receive either ST-100 Ophthalmic Solution or placebo solution as topical ophthalmic drops administered bilaterally BID for 4 weeks. Subjects, Sponsor, Contract Research Organization (CRO), and site personnel will be masked to treatment assignment. The clinical hypotheses for this study is that low dose and high dose ST-100 Ophthalmic Solution twice daily (BID) is superior to its vehicle (BID) for the primary endpoints of signs and symptoms of dry eye.