Glaucoma

Key clinical points

• Primary open-angle glaucoma (POAG) is the most common form; angle-closure is less common but can be sight-threatening acutely.
• IOP is the principal modifiable risk factor, but normal-tension glaucoma occurs at statistically normal pressures.
• Diagnosis integrates optic nerve appearance, OCT of the retinal nerve fiber layer, and standard automated perimetry.
• Treatment escalates from topical medications (prostaglandin analogs first-line) to laser trabeculoplasty, MIGS, and incisional surgery.
• Because vision loss is irreversible, the goal is early detection and slowing progression, not restoring lost field.

Overview and classification

Glaucoma encompasses several distinct diseases that share a characteristic optic neuropathy with loss of retinal ganglion cells and their axons. It is broadly classified by anterior chamber angle anatomy (open vs. closed) and by cause (primary vs. secondary).

Primary open-angle glaucoma is the most prevalent form in most populations. Primary angle-closure disease, driven by anatomic crowding of the anterior segment, carries a higher risk of acute, symptomatic pressure spikes. Secondary glaucomas include pseudoexfoliation, pigmentary, neovascular, steroid-induced, and uveitic forms.

Signs, symptoms, and risk factors

Open-angle glaucoma is typically asymptomatic until advanced, which is why it is often called a silent disease. Acute angle closure, by contrast, presents with severe pain, halos, a mid-dilated non-reactive pupil, and markedly elevated IOP requiring urgent intervention.

Established risk factors include elevated IOP, older age, family history, African or Hispanic ancestry, thinner central corneas, and higher myopia. Pseudoexfoliation and pigment dispersion increase secondary risk.

Diagnosis

A comprehensive evaluation includes IOP measurement, gonioscopy to assess the angle, dilated optic nerve examination for cupping and rim thinning, and pachymetry for central corneal thickness. Optical coherence tomography quantifies retinal nerve fiber layer and ganglion cell complex loss, often before perimetric defects appear.

Standard automated perimetry documents functional loss and is central to staging and monitoring. Because single measurements vary, longitudinal trend analysis of both structure and function is essential to distinguish true progression from noise.

Management

Lowering IOP is the only intervention proven to slow progression. Prostaglandin analogs are first-line for most patients given once-daily dosing and efficacy; beta-blockers, alpha agonists, carbonic anhydrase inhibitors, and rho-kinase inhibitors are additional classes.

Selective laser trabeculoplasty is an effective first-line or adjunctive option. Minimally invasive glaucoma surgery (MIGS) has expanded the middle ground between drops and traditional filtering surgery, while trabeculectomy and aqueous shunts remain the mainstay for advanced or refractory disease. Angle closure is additionally addressed with laser peripheral iridotomy and increasingly early lens extraction.