Glaucoma: Types, Symptoms, Diagnosis & Treatment to Prevent Vision Loss

Glaucoma is a group of optic neuropathies characterized by progressive retinal ganglion cell death and visual field loss, often (but not always) associated with elevated intraocular pressure (IOP). It is a leading cause of irreversible blindness worldwide.

Primary Types

• Primary Open-Angle Glaucoma (POAG): Most common (~90%). Trabecular meshwork drainage gradually inefficient → slow IOP rise. Asymptomatic until late peripheral field loss. Chronic, painless.
• Primary Angle-Closure Glaucoma (PACG): Iris blocks drainage angle. Can be:
  • Acute attack: Sudden IOP spike (>40–50 mmHg) → severe eye pain, headache, nausea, vomiting, halos, blurred vision, fixed mid-dilated pupil. Ophthalmic emergency.
  • Chronic: Synechial closure → gradual IOP rise.
• Normal-Tension Glaucoma (NTG): Optic nerve damage despite IOP <21 mmHg. Vascular dysregulation, structural vulnerability. Treated by lowering IOP further.
• Secondary glaucomas: Pseudoexfoliation, pigment dispersion, steroid-induced, traumatic, neovascular, uveitic.
• Congenital/childhood: Developmental angle defects; epiphora, photophobia, buphthalmos.

Risk Factors

• Age >60 ( >40 for African ancestry)
• Family history (first-degree relative: 4–9× risk)
• Elevated IOP
• Thin central corneal thickness (CCT <555 μm)
• High myopia (POAG), hyperopia (PACG)
• Diabetes, hypertension, sleep apnea, steroid use
• African, Hispanic, Asian ancestry (higher prevalence/severity)

Diagnosis

Comprehensive exam: IOP (Goldmann applanation), gonioscopy (angle), optic nerve head assessment (cup-disc ratio, RNFL defects), visual field (Humphrey 24-2), OCT (RNFL/GCC thickness), pachymetry. Serial monitoring essential.

Treatment — Goal: Lower IOP to Target Pressure

• First-line: Prostaglandin analogs (latanoprost, travoprost, bimatoprost, tafluprost) — once nightly, best efficacy/side effect profile.
• Add-ons: Beta-blockers (timolol), alpha-agonists (brimonidine), carbonic anhydrase inhibitors (dorzolamide, brinzolamide), rho kinase inhibitors (netarsudil).
• Laser: SLT (selective laser trabeculoplasty) — first-line or adjunct; LPI (laser peripheral iridotomy) for angle closure.
• Surgery: Trabeculectomy, tube shunts (Ahmed, Baerveldt), MIGS (iStent, Hydrus, Xen) — for refractory or advanced cases.

Key Message

Glaucoma is asymptomatic until advanced. Regular comprehensive eye exams (every 1–2 years >40; annually >60 or with risk factors) are the only way to catch it early. Vision lost cannot be restored — but progression can be halted.