Open-angle glaucoma

Glaucoma is the second leading cause of blindness in the world, with open-angle glaucoma being the most common type.

Frequently presents asymptomatically and may be identified on routine ophthalmic examination.

Intra-ocular pressure is most often elevated, but may be normal in some cases.

Optic disc cupping is diagnostic.

May lead to irreversible loss of peripheral vision and, later, of central vision if untreated.

Glaucoma is a neurodegenerative condition primarily due to dysfunction in outflow of the nutrient-rich fluid, aqueous humour that constantly flows through the eye. Aqueous humour, created in the ciliary body, passes through the pupil into the small area between the iris and the cornea, called the anterior chamber. The fluid then flows into the periphery of the chamber known as the anterior chamber angle. This angle is where the fluid travels through the trabecular meshwork and into blood vessels. Open-angle glaucoma is characterised by an anatomically open angle but with an obstructed and slowed drainage system outflow. The mechanism of blockage is unclear. A rise in increased intra-ocular pressure results, characterised by retinal ganglion cell damage, then peripheral vision loss in early disease and central vision loss in late disease.[1]Weinreb RN, Khaw PT. Primary open-angle glaucoma. Lancet. 2004;363:1711-1720. http://www.ncbi.nlm.nih.gov/pubmed/15158634?tool=bestpractice.com