Emerging drugs for ocular hypertension.

INTRODUCTION: Glaucoma is a prevalent ocular disease with characteristic optic disc and visual field changes. Globally, it is the second most common cause of visual disability, and the most common cause of irreversible and preventable blindness. Ocular hypertension (OH) occurs where intraocular pressure elevation occurs in the absence of glaucomatous disc and visual field changes. OH is a strong risk factor for glaucoma. Ocular hypotensive medications are the mainstay of glaucoma and OH treatment, and their use modifies the course of the disease by preventing onset and progression of damage. AREAS COVERED: Prostaglandin analogs, β-blockers, α-agonists, carbonic anhydrase inhibitors and parasympathomimetics are available in our glaucoma armamentarium and are reviewed. Novel agents have evolved as our understanding of the complex mechanisms involved in aqueous humor production and obstacles to aqueous outflow increases. Potential future candidates appear to act on enhancing trabecular meshwork outflow: the Rho-kinase inhibitors, ion-channel modulators and chelating agents. Further work is needed on other promising agents: serotonergics, melatonins, cannabinoids, adenosine agonists, components of the actomyosin system, nucleotide analogs and gene silencing. Methods to improve side effect profiles or efficacy of currently available therapies are also being developed. As glaucoma treatment adherence is poor, novel drug delivery methods might address this challenge. EXPERT OPINION: Although there are good intraocular pressure-lowering medications available, novel mechanisms and drug delivery modes may provide more effective glaucoma control in future.