A Single Centre Study to Evaluate 3 Ophthalmic Formulations in Healthy Subjects

Each subject will receive the following treatments: * Period 1: Formulation A (n = 14) or placebo (n = 7) twice daily for 7 days * Period 2: Formulation B (n = 14) or placebo (n = 7) twice daily for 7 days * Period 3: Formulation C (n = 14) or placebo (n = 7) twice daily for 7 days There will be a minimum washout of 7 days between each treatment period (last dose of previous period to first dose of subsequent period