Glaucoma is an optic neuropathy characterised by optic nerve degeneration associated with
visual field defects. It remains the world’s number one cause of irreversible blindness and
patients usually present at late stage of the disease since it is generally asymptomatic until
severe. The disease is subdivided into primary and secondary with primary open-angle
glaucoma (POAG) being the most common type. At present, lowering the intraocular pressure
(IOP) remains the only proven efficient approach in delaying the onset or preventing the
progression of the disease. Medical treatment with topical antiglaucoma agents is the
treatment of choice in open angle glaucoma. The use of antiglaucoma drugs aims to reduce
IOP by enhancing aqueous humour (AH) outflow, reducing AH production, or both. The choice
to use any available treatment option should be carefully considered in an attempt to maximise
benefits and reducing the risk of developing adverse drug reactions. This review highlights the
six classes of ocular hypotensive agents currently in use for POAG treatment including
prostaglandin analogues; -adrenergic receptor blockers; -2 adrenergic receptor stimulants;
carbonic anhydrase inhibitors; muscarinic receptor stimulants; rho kinase inhibitors with
regards to their mechanism/s of action and potential adverse drug reactions, and
antiglaucoma fixed drug combinations.