Glaucoma

Glaucoma is a group of progressive optic neuropathies characterized by retinal ganglion cell loss, optic disc cupping and corresponding visual field defects. Primary open-angle glaucoma (POAG) is the most common form and develops insidiously without symptoms in early stages. Angle-closure, normal-tension, congenital and secondary forms (uveitic, traumatic, neovascular, pseudoexfoliative, pigmentary) have distinct mechanisms.

The principal risk factor is elevated intraocular pressure (IOP) due to imbalance between aqueous humor production and outflow through the trabecular meshwork. Other factors include older age, family history, African or Asian ancestry, thin central cornea, myopia, diabetes and prolonged steroid use. Vascular dysregulation contributes to normal-tension glaucoma.

Disease progression silently narrows peripheral vision before central vision is affected; without treatment it leads to tunnel vision and blindness. Acute angle-closure crisis presents with sudden severe eye pain, blurred vision, halos, headache and nausea and is an ophthalmologic emergency.