Which drug reduces intraocular pressure by decreasing the formation of the aqueous humor?

When applied topically to the eye, both the direct-acting cholinomimetic agents (e.g., pilocarpifle) and those cholinomimctic drugs that act by inhibition of AChE (e.g.. echothiophate, isofluorphate. and physostigmine) cause miosis by contracting the sphincter muscle of the iris and reducing ocular pressure by contracting the ciliary muscle. In patients with glaucoma, this latter effect permits greater drainage of the aqueous humor through the trabecular meshwork in the canal of Schlemm and a reduction in resistance to outflow of the aqueous humor. Ceain b-adrenergic blocking agents (e.g., timolol and levobunolol) applied to the eye are also very useful in treating chronic wide-angle glaucoma. These drugs appear to act by decreasing the secretion (or formation) of the aqueous humor by antagonizing the effect of circulating catecholamines on 13- b-adrenergic receptors in the ciliary epithelium