 Topical IOP-lowering therapy has the advantage of providing a drug level directly to the end organ with very little or no systemic absorption thereby reducing side effect potential. There is very little information in the ophthalmic literature regarding potential drug interactions between topical IOP-lowering medications and other medications taken orally for other medical reasons. Patients will be randomized to either latanoprost or brimonidine. Patients in both groups will be randomized to either placebo or ibuprofen for the first 14 days and then crossed over to the other treatment for 14 days. 