Abstract
Glaucoma is a major cause of vision loss worldwide with nearly 8 million people bilaterally blind from the disease. This number is estimated to increase over the next 10 years. The key to preventing blindness from glaucoma is effective diagnosis and treatment. The classical glaucoma treatment focuses on intraocular pressure (IOP) reduction. Better knowledge of the pathogenesis has opened up additional therapeutical approaches often called non-IOP lowering treatment. Whilst most of these new avenues of treatment are still in the experimental phase, others are already used by some physicians. These new therapeutic approaches allow a more personalised patient treatment. Non-IOP lowering treatment includes improvements of ocular blood flow, particularly blood flow regulation. This can be achieved by improving the regulation of ocular blood flow (improving autoregulation) by drugs such as carbonic anhydrase inhibitors, magnesium or calcium channel blockers. It can also be improved by decreasing blood pressure over-dips. Blood pressure can be increased by an increase in salt intake or in rare cases by treatment with fludrocortisone. Experimentally, glaucomatous optic neuropathy can be prevented by inhibition of astrocyte activation, either by blockage of epidermal growth factor receptor or by counteracting Endothelin. Glaucomatous optic neuropathy can also be prevented by nitric oxide-2 synthase inhibition. Suppression of matrix metalloproteinase-9 inhibits apoptosis of retinal ganglion cells and tissue remodelling. Upregulation of heat shock proteins protects the retinal ganglion cells and the optic nerve head. Reduction of oxidative stress especially at the level of mitochondria also seems to be protective. This can be achieved by gingko, dark chocolate, polyphenolic flavonoids occurring in tea, coffee or red wine and anthocyanosides found in bilberries as well as by ubiquinone and melatonin. This review describes the individual mechanisms which may be targeted by non-IOP lowering treatment based on our pathogenic scheme.