Controversies in Glaucoma: Current Medical Treatment and Drug Development

Elevated eye pressure is the main risk factor for glaucoma; intraocular pressure rises when the ratio between aqueous humor formation (inflow) and its outflow is unbalanced. Currently, the main goal of medical treatment is the reduction of intraocular pressure. Five main classes of topical drugs are available; they include betablockers, carbonic anhydrase inhibitors, prostaglandin derivatives, sympathomimetics and miotics. Beta-blockers and carbonic anhydrase inhibitors slow the formation of aqueous humor and may be considered as "inflow" drugs; the other three classes reduce the resistance to the drainage of aqueous humor and may be considered as "outflow" drugs. Despite the variety of drugs accessible in the market, there is a real need for ophthalmologists to have more potent medications for this disease. This review focuses on medical treatment of glaucoma with particular attention to novel molecules in pre-clinical or clinical development.