Glaucoma and optic nerve · AL
Glaucoma eye drops
Five mechanisms · adherence · drop technique · no brand names
Last reviewed: 2026-10-06 · 潘家健醫生
Key points
- Glaucoma drops are taught by mechanism class — no brand names; adherence matters.
- Do not self-change dose, stop, or share leftover bottles.
- Severe pain with headache/vomiting, rainbows or sudden vision drop: A&E now (rule out acute angle closure).
- Drop technique is on the drops page; target-IOP monitoring is on the glaucoma-monitoring page.
What they are
Long-term care for most open-angle glaucoma and ocular hypertension relies on lowering eye pressure to slow optic-nerve damage. Aqueous humour is made by the ciliary body and leaves via the trabecular meshwork and uveoscleral pathway. Pressure-lowering drops are prescription medicines chosen by an ophthalmologist. This page explains classes only — no product names. See also the glaucoma-monitoring hub (target IOP, OCT / visual field and reports) and the glaucoma overview.
Five topical classes (mechanism and education ballparks)
| Class | Main mechanism | Education points |
|---|---|---|
| Prostaglandin analogues (PGA) | Increase uveoscleral outflow | Literature: single-agent pressure drop is often clinically meaningful; usually once at night; lashes, iris/periocular pigment; caution in active uveitis or CME |
| Beta-blockers | Reduce aqueous production | Discuss asthma/COPD and some heart-rhythm issues; systemic absorption can affect heart rate |
| Carbonic-anhydrase inhibitors (topical CAI) | Reduce aqueous production | Tell the doctor about sulphonamide allergy; stinging or taste change possible |
| Alpha-2 agonists (e.g. brimonidine class) | Reduce production and aid outflow | Avoid / extreme caution in infants (CNS depression); dry mouth, fatigue, allergic conjunctivitis |
| Rho-kinase (ROCK) inhibitors | Act on trabecular outflow | Conjunctival hyperaemia or subconjunctival haemorrhage may occur |
Fixed combinations put two classes in one bottle to cut drop count — a concept only; no branded combos are compared here. Switching or adding is a doctor’s decision.
Adherence
Studies often report imperfect adherence among people on glaucoma drops. Missed doses and silent stopping are preventable reasons for worsening — if side effects are hard, return for a change rather than stopping alone.
Drop technique and punctal occlusion (education)
- Wash hands; shake if the label says so
- Tilt back, pull the lower lid; do not touch the tip to the eye or lashes
- Close the eye gently for about one to two minutes; light punctal pressure can reduce nasal absorption
- Space two drops by several minutes (often taught as about five); thin before thick — follow the label and demo
- See also the correct-drop-use page and the drops tool
Systemic carbonic-anhydrase inhibitors (e.g. acetazolamide class)
In an acute attack or very high pressure, A&E or a specialist may use oral or intravenous CAIs. This is not a home “rescue pill” and this page has no DIY dose schedule. Serious risks include electrolyte upset, blood dyscrasias and severe sulphonamide-related skin reactions (including Stevens–Johnson syndrome) — allergy, kidney disease and electrolyte problems are for the treating doctor to check.
This is general medical information, not a diagnosis, and cannot replace an in-person consultation with a registered ophthalmologist, refraction, or a dilated fundus exam. It is not advice to use any medicine or undergo any procedure. Medicines (including off-label use), laser or surgery must be decided by a registered doctor after examination, according to indications and Hong Kong registration. Figures from the literature are published averages, not any clinic’s results. This site does not book, prescribe or refer. Do not change treatment on your own.