Pharmacotherapy of glaucoma

Abstract

Glaucoma is a group of diseases involving the optic nerve and associated structures, which is characterized by progressive visual field loss and typical changes of the optic nerve head (ONH). The only known treatment of the disease is reduction of intraocular pressure (IOP), which has been shown to reduce glaucoma progression in a variety of large-scale clinical trials. Nowadays, a relatively wide array of topical antiglaucoma drugs is available, including prostaglandin analogues, carbonic anhydrase inhibitors, beta-receptor antagonists, adrenergic agonists, and parasympathomimetics. In clinical routine, this allows for individualized treatment taking risk factors, efficacy, and safety into account. A major challenge is related to adherence to therapy. Sustained release devices may help minimize this problem but are not yet available for clinical routine use. Another hope arises from non-IOP-related treatment concepts. In recent years, much knowledge has been gained regarding the molecular mechanisms that underlie the disease process in glaucoma. This also strengthens the hope that glaucoma therapy beyond IOP lowering will become available. Implementing this concept with clinical trials remains, however, a challenge.

FIG. 1.

Schematic illustration of aqueous humor dynamics. Aqueous humor is produced by the epithelium of the ciliary body (A) and flows into the anterior chamber through the pupil. Most of it then leaves the anterior chamber via the trabecular meshwork into the Schlemm's canal (B). Some aqueous humor also leaves the eye through the iris root (uveoscleral outflow, C).

FIG. 2.

Influence of different substances on aqueous humor dynamics. Intraocular pressure (IOP) is determined by the inflow and outflow of aqueous humor in the eye. Glaucoma medications therefore either reduce aqueous humor production or increase trabecular or uveoscleral outflow.