This is a multi-center, double-masked, randomized, vehicle-controlled study testing PL9643, an ophthalmic solution, to determine the safety and efficacy against a vehicle in dry eye patients.

During a 2-week/14-day study run-in period (for the purpose of subject selection) prior to randomization, all subjects will receive Vehicle Ophthalmic Solution (vehicle) bilaterally three times a day. Randomization will then occur in a 1:1 ratio where patients will be assigned to receive PL9643 ophthalmic solution given bilaterally three times a day or vehicle ophthalmic solution administered bilaterally three times a day. The treatment period is 12 weeks.