Current management of glaucoma and the need for complete therapy

Glaucoma is a long-term ocular neuropathy defined by optic disc or retinal nerve fiber structural abnormalities and visual field abnormality. Primary open-angle glaucoma is the most common type of glaucoma. Currently available treatments, initiated in a stepwise process, focus on intraocular pressure (IOP) reduction, and initially include topical drug therapy (single then multidrug combinations), followed by laser then surgical treatment. Topical prostaglandin analogues or beta-adrenergic receptor blockers are first used, followed by alpha-agonists or topical carbonic anhydrase inhibitors, and infrequently, cholinergic agonists and oral therapy. Limitations to existing topical IOP-reducing medications include continued disease progression in glaucoma patients with normal IOP, treatment failure, and low rates of compliance and persistence. Therapeutic agents under investigation include neuroprotectants, which target the disease process manifested by death of retinal ganglion cells, axonal loss, and irreversible loss of vision. Neuroprotectants may be used alone or in combination with IOPreducing therapy (a treatment strategy called complete therapy). Memantine, an N-methyl-D-aspartate receptor blocker currently approved for dementia, is the neuroprotectant farthest along in the process seeking regulatory approval for glaucoma treatment and has a favorable safety profile because of its selective mechanism of action. Several other neuroprotectants are in early stage investigation. Complete therapy provides hope for improved outcomes by reducing the significant morbidity and economic consequences that occur as a result of neurodegeneration and disease progression.