The therapeutic management of glaucoma costs the United States and the United Kingdom about 2.5 billion and 216 million USD annually, respectively.
Mainstay for treatment is reduction and control of intraocular pressure (IOP) by reduction through the use of medications, laser, or surgery as appropriate. As the blood retinal barrier restricts most therapies from travelling from the blood stream to the eye, most glaucoma treatments are topical in the form of eye drops. Treatments aim to reduce IOP, by decreasing the aqueous humour in the eye or by increasing its outflow through the eye’s established drainage pathways. Classes of drugs most commonly used are:
Prostaglandin analogues are a class of medication that can reduce intra ocular pressure by working as vasodilators. This means they expand the blood vessels in your eye. This helps aqueous humour leave the eye through the uveoscleral pathway. From there, it is disposed through the lymph system. This class of medication can reduce IOP by an average 18–31 percent with relatively minor side effects. Generic names include: latanoprost; bimatoprost; travoprost; tafluprost; unoprostone; and latanoprostene bunod ophthalmic solution.
Beta blockers cause your body to produce and secrete less aqueous humour, which leads to an average 20–27 percent IOP reduction. Generic names include: timolol; levobunolol; carteolol; metipranolol; and betatoxol.
Alpha adrenergic (A2) agonists reduce production of aqueous humour and increase its outflow through the uveoscleral pathway, achieving an approximate 13-29 percent IOP reduction. Generic names include: brimonidine; dipivefrin; apraclonidine; and epinephrine.
Carbonic anhydrase inhibitors lower aqueous humour volume by partially inhibiting enzymes responsible for its production. This can lower IOP by approximately 15-20 percent. They also may improve blood flow to the retina and optic nerve. Generic names include: [Eye drops]: dorzolamide and brinzolamide; [Oral forms] acetazolamide and methazolamide.
Cholinergic agents cause eye tissues to contract, opening drainage pathways and increasing outflow for a 15-25 percent reduction in IOP. Generic names include: pilocarpine; echothiophate and an ophthalmic gel ointment, pilocarpine.
Hyperosmotic agents rapidly lower IOP by decreasing vitreous volume, or the gel-like fluid that fills the cavity behind the lens of the eye. The accompanying side effects can be severe. Thus, these drugs are not used for long-term treatment, but to temporarily reduce eye pressure in acute situations until another effective treatment can be established. Generic names include: glycerine or isosorbide (both oral formulations) and mannitol (intravenous).
A Rho kinase inhibitor is believed to reduce IOP by increasing the outflow of aqueous humour (the fluid inside the eye) through the trabecular meshwork, the main fluid drain of the eye. The generic name is: netarsudil ophthalmic solution.
Combination medications in a single formulation can be used to achieve better results. They include eye drops with the following generic names: dorzolamide and timolol; latanoprost and timolol; brimonidine and timolol, and brimonidine and brinzolamide.