Which of the following glaucoma medications do NOT lower IOP by increasing aqueous outflow?

Timolol is a non-selective beta-adrenergic antagonist that lowers intraocular pressure (IOP) primarily by reducing the production of aqueous humor rather than increasing aqueous outflow. It works by blocking beta receptors in the ciliary body, leading to decreased aqueous humor formation and consequently lowering IOP.

The other options listed—Latanoprost, Pilocarpine, and Brimonidine—act through different mechanisms that include increasing the outflow of aqueous humor. For example, Latanoprost, a prostaglandin analog, enhances uveoscleral outflow, while Pilocarpine, a cholinergic agonist, promotes the opening of the trabecular meshwork, facilitating aqueous outflow. Brimonidine, an alpha agonist, has a component of both decreasing aqueous humor production and increasing outflow, especially through the uveoscleral pathway.

Thus, Timolol is the only medication among the choices that predominantly functions by reducing the amount of aqueous humor produced, rather than increasing its outflow.