Glaucoma

Glaucoma is progressive injury to the optic nerve, usually reflected by retinal ganglion-cell and axonal loss, optic-nerve cupping, thinning of the retinal nerve fiber layer or macular ganglion-cell layer, and characteristic visual-field defects. Elevated intraocular pressure (IOP) is the principal modifiable risk factor, but it is not the definition of glaucoma; a patient may have glaucomatous damage despite an IOP in the statistically normal range. Primary open-angle glaucoma (POAG) often develops without symptoms. Peripheral field loss can advance while central visual acuity remains normal, so a good Snellen result does not exclude clinically significant disease. By contrast, acute angle-closure crisis produces sudden painful visual symptoms and gastrointestinal distress and can permanently damage vision within hours. Recognizing which pattern is present determines whether the priority is longitudinal treatment and adherence support or immediate ophthalmic emergency care. For asymptomatic adults aged 40 years and older, the U.S. Preventive Services Task Force has found insufficient evidence to judge the balance of benefits and harms of primary-care screening for POAG. That statement is not a reason to delay evaluation of a patient with visual...