What is the main mechanism of action for beta blocker ophthalmic medications?

Beta blocker ophthalmic medications primarily act by decreasing aqueous humor production in the ciliary body of the eye. This reduction in aqueous humor leads to a decrease in intraocular pressure, which is particularly beneficial in the management of glaucoma. The mechanism involves blocking beta-adrenergic receptors, which decreases the stimulation that leads to aqueous secretion.

While there are other mechanisms involved in glaucoma treatment, such as increasing outflow of aqueous humor, the hallmark action of beta blockers is their ability to suppress aqueous humor formation rather than enhancing its drainage through the trabecular or uveoscleral pathways. By understanding this primary action, it becomes clear why decreasing aqueous production is the correct answer in this context.