Primary open-angle glaucoma

Acute angle-closure glaucoma is a pupillary-block emergency in which sudden closure of the iridocorneal angle blocks aqueous outflow, causing severe eye pain, halos, and rapidly rising intraocular pressure that can blind the eye within hours if not treated. Diagnosis is clinical plus tonometry and gonioscopy; treatment is immediate topical and systemic IOP-lowering therapy followed by laser peripheral iridotomy.

Age-related macular degeneration is a leading cause of irreversible blindness in older adults in resource-rich countries, presenting as painless central vision loss from drusen and retinal pigment epithelium change (dry AMD) or choroidal neovascularization (wet AMD). Dry AMD is managed with AREDS2 supplementation and risk-factor control; wet AMD is treated with intravitreal anti-VEGF injection.

Central retinal vein occlusion causes sudden, painless, variable monocular vision loss from thrombosis of the central retinal vein, is treated with intravitreal anti-VEGF for macular edema, and carries a real risk of neovascular glaucoma in the ischemic subtype.

Central retinal artery occlusion is sudden, painless, profound monocular vision loss from embolic or thrombotic occlusion of the central retinal artery, an ocular stroke equivalent in which irreversible retinal infarction begins around 90 minutes after complete occlusion. Diagnosis is clinical on dilated fundoscopy, and management pairs time-critical reperfusion attempts with an emergency embolic and giant-cell-arteritis workup to protect the fellow eye and prevent a subsequent stroke.

Cataract is age-related or secondary opacification of the crystalline lens causing painless, progressive glare and vision loss, diagnosed clinically by lens opacity and a diminished red reflex, and treated definitively with phacoemulsification and intraocular lens implantation when vision-impairing.

Optic neuritis is inflammatory demyelination of the optic nerve, usually a presenting event of multiple sclerosis, causing subacute painful monocular vision loss with a relative afferent pupillary defect. Confirm with MRI orbits/brain and treat with IV methylprednisolone followed by an oral prednisone taper, never oral prednisone alone.

Sudden painless monocular vision loss from occlusion of the posterior ciliary artery by giant cell arteritis infarcts the optic nerve head and threatens the fellow eye within days. Treatment with high-dose glucocorticoids must begin on clinical suspicion, before biopsy confirmation, because established blindness is usually permanent.

Uveitis is inflammation of the uveal tract, classified by anatomic location as anterior, intermediate, posterior, or panuveitis and by systemic association such as HLA-B27 spondyloarthritis, sarcoidosis, or Behcet disease. Anterior uveitis presents with a painful red eye and photophobia diagnosed at the slit lamp, while posterior uveitis presents with painless floaters or vision loss, and treatment is topical corticosteroid for anterior disease escalating to systemic corticosteroid and steroid-sparing immunosuppression for recurrent, severe, or posterior-segment disease.

Rhegmatogenous retinal detachment is a surgical emergency in which a full-thickness retinal break lets liquefied vitreous separate the neurosensory retina from the retinal pigment epithelium, presenting with flashes, floaters, and an advancing visual field curtain. Diagnosis is by dilated indirect ophthalmoscopy with scleral depression, and treatment is prompt surgical reattachment, most urgent while the fovea is still spared.