What Is Glaucoma?
Glaucoma is a group of eye conditions that damage the optic nerve, usually because of raised pressure inside the eye (intraocular pressure). It causes permanent vision loss — typically starting with peripheral vision — and is the leading cause of irreversible blindness worldwide.
Types of Glaucoma
| Type | Key Features |
|---|---|
| Open-angle glaucoma (90%) | Chronic, no symptoms until late; raised IOP; peripheral vision loss first |
| Angle-closure glaucoma | Sudden onset; severe eye pain, headache, blurred vision, halos — emergency |
| Normal-tension glaucoma | Optic nerve damage despite normal IOP — poor blood flow to nerve |
| Secondary glaucoma | Result of another condition: diabetes, steroids, trauma, uveitis |
Acute Angle-Closure Attack — Emergency:Sudden, severe eye pain with headache, nausea, vomiting, blurred vision and seeing coloured halos around lights. Go to A&E immediately — can cause blindness within hours without treatment.
Diagnostic Tests
| Test | Purpose |
|---|---|
| Tonometry | Measures intraocular pressure |
| Visual field testing (perimetry) | Maps areas of vision loss |
| Optic disc examination (slit lamp + dilated) | Assesses cup-to-disc ratio and nerve damage |
| OCT (Optical Coherence Tomography) | High-resolution retinal nerve fibre layer thickness |
| Gonioscopy | Examines the drainage angle of the eye |
Blood Tests Related to Glaucoma Risk
- Blood glucose and HbA1c — diabetes doubles glaucoma risk
- Blood pressure — hypertension and hypotension both affect optic nerve blood flow
- Thyroid function — thyroid disease is associated with normal-tension glaucoma
FAQs
Can glaucoma be cured?
No — optic nerve damage is irreversible. Treatment (eye drops, laser, surgery) slows or stops progression. Early detection is critical.
Who should be screened for glaucoma?
Everyone over 40, those with a family history of glaucoma, people of African or Caribbean descent (higher risk), and all people with diabetes.
Do glaucoma drops have side effects?
Common: redness, eye irritation. Some drops (prostaglandins) can change eyelash length and iris colour. Beta-blocker drops can affect blood pressure and cause breathing difficulties in asthmatics.
Medical Disclaimer: Glaucoma screening every 1–2 years is recommended for over-40s and high-risk groups. Vision loss cannot be reversed — prevention requires early detection.