Glaucoma: a review of adjunctive therapy and new management strategies.

Glaucoma is a major cause of vision loss throughout the world. Treatment for glaucoma consists of reducing intraocular pressure (IOP) to an acceptable target range to prevent further optic nerve damage. Typically, this involves the selection of a topical IOP-lowering agent. Five major classes of glaucoma medications are presently available for clinical use. These include alpha-adrenergic agonists, beta-adrenergic antagonists (beta-blockers), carbonic anhydrase inhibitors (CAIs), cholinergics and prostaglandin analogs (PGAs). Although beta-blockers enjoyed great success as first-line glaucoma therapy for many years, recently the PGAs have gained favor as the initial treatment of choice for most patients. Although the PGAs offer robust IOP reduction as monotherapy, a significant number of patients will require an adjunctive agent for adequate IOP control. Recent studies have demonstrated that alpha-agonists, beta-blockers and CAIs can be used safely and effectively as adjunctive therapy for patients being treated with a PGA. Comparison studies are beginning to appear in the literature to help determine which adjunctive agent is the most effective when used in combination with a PGA. Additional IOP-lowering efficacy with adjunctive therapy does have limitations, particularly with the addition of a third or fourth agent. For those patients on maximal tolerated medical therapy who still need additional IOP reduction, other available options include laser trabeculoplasty and filtration surgery.