Glaucoma is characterized by an accelerated loss of retinal ganglion cells, as a result of damage to optic nerve axons. One factor involved in the disease process is elevated intraocular pressure (IOP) and this is the current focus of therapies. However, up to 45% of patients experience glaucoma progression despite good IOP control and partly as a result, the treatment principle of direct neuroprotection has been developed, which consists of treating optic nerve degeneration in glaucoma independently of IOP lowering. Animal models have shown the potential of this approach but there are limited clinical trial data. Brimonidine and memantine currently show promise, in terms of efficacy and side effects, among the compounds entering clinical trials. Brimonidine has been shown to have a neuroprotective effect independent of IOP lowering in humans with glaucoma, and data from a large clinical trial are being analyzed. Memantine has shown neuroprotective effects in animal models of glaucoma, and data from a clinical trial in humans are awaited.
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