Glaucoma Eye Drops

Concise summaries of glaucoma eye drops used in ophthalmic and optometric practice in Singapore, including practical guidance on pharmacology, dosing, patient selection, systemic precautions, and referral pathways.

Last updated: March 2026

What are glaucoma eye drops?

Glaucoma eye drops are topical ophthalmic agents that lower intraocular pressure (IOP) by reducing aqueous humour production, increasing aqueous outflow, or both. IOP reduction remains the only proven, modifiable therapeutic target in glaucoma management, slowing optic nerve damage and visual field progression across all glaucoma subtypes.^[1]

Glaucoma is the leading cause of irreversible blindness globally and carries a particularly high burden in Singapore and across Asia. Primary open-angle glaucoma (POAG) affects approximately 3.2% of Singaporeans aged over 40, while primary angle-closure glaucoma (PACG) — due to the shallow anterior chamber anatomy prevalent in East Asian populations — is disproportionately prevalent in Singapore compared with Western cohorts. Normal-tension glaucoma (NTG) represents a large proportion of open-angle cases in Singaporean and broader Asian populations.^[2,3]

Drug classes

Prostaglandin analogues (PGAs) — current first-line agents; increase uveoscleral (and trabecular) outflow; dosed once nightly; IOP reduction ~25–35%. Examples: latanoprost, bimatoprost, travoprost, tafluprost.
Beta-adrenergic blockers — reduce aqueous humour production by blocking β2-receptors in the ciliary body; dosed OD or BD; IOP reduction ~20–25%. Non-selective (timolol) and cardioselective (betaxolol) agents available. Systemic cardiovascular and respiratory adverse effects require careful patient selection.
Carbonic anhydrase inhibitors (CAIs) — reduce aqueous production by inhibiting carbonic anhydrase II/IV in the ciliary body; IOP reduction ~15–20%. Examples: dorzolamide (Trusopt), brinzolamide (Azopt). Oral acetazolamide is reserved for acute angle-closure emergencies.
Alpha-2 adrenergic agonists — dual mechanism: reduce aqueous production and increase uveoscleral outflow; brimonidine has putative neuroprotective properties relevant to NTG management in Singapore. IOP reduction ~20–25%. Significant allergy rate with prolonged use.
Fixed-dose combinations — pre-combined formulations (PGA + beta-blocker, CAI + beta-blocker, CAI + alpha-2 agonist) simplify multi-drug regimens, reduce BAK exposure, and improve adherence — a critical factor in the long-term management of a typically asymptomatic, lifelong disease.

Who are they for?

Glaucoma drops are indicated for patients with diagnosed glaucoma or ocular hypertension (OHT) requiring IOP-lowering therapy. Given that glaucoma is often asymptomatic until advanced stages, Singapore optometrists play a pivotal frontline role in detecting optic disc changes, elevated IOP, and visual field defects during routine eye examinations — and must refer promptly. The Singapore Epidemiology of Eye Disease (SEED) programme data highlight that a substantial proportion of glaucoma cases in Singapore remain undiagnosed at first presentation to optometry.^[3]

Patient profiles and common conditions

Primary open-angle glaucoma (POAG)

Most common glaucoma subtype; insidious onset; typically asymptomatic until late. Elevated IOP with open angle, optic disc cupping, and visual field loss. First-line: PGA OD.

Normal-tension glaucoma (NTG)

IOP consistently ≤21 mmHg despite typical glaucomatous disc and field damage. Disproportionately prevalent in Singapore/Asian populations. Brimonidine preferred for potential neuroprotective benefit.

Primary angle-closure glaucoma (PACG)

Higher prevalence in East Asian/Singapore Chinese populations due to shallower anterior chamber anatomy. Peripheral iridotomy and IOP-lowering therapy; PGAs and beta-blockers used post-laser.

Ocular hypertension (OHT)

Elevated IOP (≥24 mmHg) without disc or field damage. Treatment decision based on IOP level, corneal thickness, family history, and risk scoring. Refer to ophthalmologist for assessment.

Secondary glaucoma

Includes pseudoexfoliative glaucoma (common in elderly Singaporeans), pigmentary glaucoma, steroid-induced glaucoma, and neovascular glaucoma. Treat underlying cause alongside IOP lowering.

Glaucoma suspect

Suspicious optic disc (vertical C:D ratio ≥0.6, asymmetry ≥0.2) or borderline IOP or visual field changes without confirmed diagnosis. Refer to ophthalmologist for full work-up; monitor in primary care.

Caution — contact lens wearers

Many glaucoma drops contain benzalkonium chloride (BAK) as a preservative, which adsorbs onto soft contact lenses and can cause toxic keratopathy with prolonged exposure. In Singapore's large contact lens-wearing population, this is an especially relevant counselling point as glaucoma patients are often on lifelong multi-drop regimens. Advise patients to remove soft lenses before instilling preserved glaucoma drops and to wait at least 15 minutes before reinsertion. Preservative-free alternatives (e.g., Saflutan unit-dose, Cosopt PF) should be considered when possible for long-term users. Rigid gas-permeable lens wearers should follow the same waiting period.

When should they be prescribed?

First-line IOP-lowering therapy

A prostaglandin analogue (PGA) dosed once nightly is the established first-line agent for POAG and OHT in Singapore clinical practice, consistent with the European Glaucoma Society guidelines and local ophthalmology protocols. PGAs achieve the greatest IOP reduction of any single-agent class (~25–33%) with once-daily dosing that supports adherence. Target IOP is individualised — typically a 20–30% reduction from baseline — and reviewed at 4–6 weeks after initiation.

Adjunctive and combination therapy

When a single PGA fails to achieve the target IOP, a second agent (typically a beta-blocker, CAI, or alpha-2 agonist) is added. Fixed-dose combinations (Cosopt, DuoTrav, Ganfort) are preferred over separate drops where available, reducing dosing frequency, minimising cumulative BAK exposure, and improving long-term adherence — a critical consideration in Singapore's largely asymptomatic glaucoma population. Selective laser trabeculoplasty (SLT) may be considered as primary or adjunctive therapy following ophthalmologist evaluation.

Escalation and urgent referral

Any patient with progressive visual field loss or disc deterioration despite optimised medical therapy should be referred to an ophthalmologist for consideration of SLT, trabeculectomy, or minimally invasive glaucoma surgery (MIGS). Acute angle-closure (AAC) with sudden severe eye pain, nausea/vomiting, corneal oedema, and mid-dilated fixed pupil is a same-day ophthalmic emergency— refer immediately without delay. Singapore optometrists detecting any sign of AAC must not attempt management and must direct the patient to emergency ophthalmic care without delay.

Presentation	Recommended agent	Referral / Duration
Suspected glaucoma / glaucoma suspect	No optometric prescribing — refer	Ophthalmology referral; baseline tests
OHT or early POAG — first-line	PGA (latanoprost/bimatoprost) OD	Ophthalmologist; review IOP at 4–6 weeks
NTG	PGA ± brimonidine (neuroprotective benefit)	Ophthalmologist; monitor visual fields 6-monthly
POAG — inadequate IOP control	Add beta-blocker or CAI; or fixed combination	Ophthalmologist; step-up therapy
PACG (post-iridotomy)	PGA, beta-blocker, or CAI per residual IOP	Ophthalmologist; long-term surveillance
Acute angle-closure (AAC)	EMERGENCY — do not manage in optometric setting	Same-day emergency ophthalmic care

Where are they available in Singapore?

In Singapore, all glaucoma eye drops are regulated by the Health Sciences Authority (HSA) under the Medicines Act (Cap. 176). Every agent in this class — prostaglandin analogues, beta-blockers, carbonic anhydrase inhibitors, alpha-2 agonists, and fixed combinations — is classified as a Prescription-Only Medicine (POM). None are available OTC or as pharmacy-only medicines. Supply is exclusively through licensed retail pharmacies on presentation of a valid prescription from a registered medical practitioner.^[4]

Scope of practice — Singapore optometrists

Under the Optometrists and Opticians Act (Cap. 213A) and regulations administered by the Optometrists and Opticians Board (OOB), Singapore-registered optometrists are authorised to examine eyes, measure IOP (non-contact or applanation tonometry), assess optic disc morphology, and perform visual field testing. They do not have the authority to prescribe, supply, or administer any therapeutic medications — including all glaucoma drops. Any patient in whom glaucoma, suspected glaucoma, OHT, or acute angle-closure is detected must be referred to a registered medical practitioner — typically an ophthalmologist — for diagnosis confirmation and initiation of treatment.^[5,6]

Prescription-only (POM): All glaucoma drops without exception — including prostaglandin analogues (Xalatan, Lumigan, Travatan, Saflutan), beta-blockers (Timoptic, Nyogel), CAIs (Trusopt, Azopt), alpha-2 agonists (Alphagan P), and fixed combinations (Cosopt, DuoTrav, Ganfort) — require a valid prescription. Optometrists detecting glaucoma or OHT must refer and may not prescribe.
Hospital formularies: PGAs, timolol, dorzolamide, brimonidine, and common fixed combinations are standard items on major public hospital formularies. Dispensing is in-house or via linked hospital pharmacies following ophthalmologist prescription.
Private ophthalmology clinics: Glaucoma drops are prescribed at private clinics and dispensed by licensed retail pharmacies with valid prescription. Chronic repeat prescriptions are common given the lifelong nature of glaucoma therapy.
Subsidised medications (CHAS / Medifund): For patients eligible under the Community Health Assist Scheme (CHAS) or Medifund, subsidised glaucoma medications are available at polyclinics and restructured hospitals. Latanoprost, timolol, dorzolamide, and brimonidine are on the subsidised drug list.
HSA product verification: Current registration status for all glaucoma agents can be verified via the HSA product registration portal (hsa.gov.sg). Always confirm current registration before recommending or referring for a specific product.^[4]

Why use topical glaucoma drops?

Topical IOP-lowering drops deliver pharmacologically active concentrations directly to the trabecular meshwork, ciliary body, and uveal vasculature — the primary sites of aqueous humour dynamics — while minimising systemic drug exposure compared with oral carbonic anhydrase inhibitors (e.g., acetazolamide), which carry significant systemic side effects and are reserved for acute angle-closure emergencies.

Proven neuroprotection via IOP reduction

Every 1 mmHg reduction in IOP reduces glaucomatous progression risk by approximately 10–13% (OHTS, EMGT data). Topical drops are the safest, most sustainable method of achieving this.

Lower systemic load vs. oral CAIs

Oral acetazolamide causes metabolic acidosis, renal stones, paraesthesia, and fatigue; topical CAIs and beta-blockers achieve clinically meaningful IOP reduction with substantially less systemic burden.

Tailored step-up therapy

The drug class spectrum allows individualised, stepwise regimen construction — from PGA monotherapy to dual or triple combinations — without surgery or laser in early-to-moderate disease.

Once-daily options support long-term adherence

Once-nightly PGAs and OD beta-blocker gel formulations (Nyogel) are critical in a largely asymptomatic disease where patient motivation and adherence are the primary barriers to effective treatment.

Selective laser trabeculoplasty (SLT) is an evidence-based alternative or adjunct to drops for open-angle glaucoma (LiGHT trial), and may be offered as initial therapy by ophthalmologists in Singapore. However, medical therapy with topical drops remains the dominant first-line approach in current Singapore practice, with laser and surgical options reserved for inadequate medical response or advanced disease.^[7]

How to use glaucoma drops — patient instructions

Instillation technique

Wash hands thoroughly with soap and water before handling the bottle or touching the eye area.
Tilt head back and gently pull down the lower eyelid with one finger to create a lower fornix pocket.
Hold the bottle inverted above the eye and instil one drop into the lower fornix — do not allow the bottle tip to contact the eye, eyelids, or eyelashes to prevent microbial contamination.
Immediately close the eye gently and apply nasolacrimal occlusion — press a fingertip firmly to the inner corner of the eye (lacrimal sac area) for at least 2 minutes. This is critical for glaucoma drops: nasolacrimal drainage is the primary route of systemic absorption, and beta-blockers in particular carry significant cardiovascular and respiratory risks via this route.
If using more than one drop type, wait at least 5 minutes between each preparation to avoid dilution and washout of the first agent.
Recap the bottle immediately after use; store as directed. Latanoprost (Xalatan) must be refrigerated (2–8°C) until first opening; most other glaucoma drops can be stored at room temperature after opening. Discard within 4–6 weeks of opening as directed on the label.

Contact lens guidance

Remove soft contact lenses before instilling any glaucoma drop. Most glaucoma drops contain BAK, which absorbs into and degrades soft lens material and causes toxic keratopathy over time.
Wait at least 15 minutes after instilling preserved glaucoma drops before reinserting soft contact lenses. For multi-drop regimens, wait 15 minutes after the final drop.
For patients with glaucoma and significant dry eye (common comorbidity), preservative-free formulations (e.g., Saflutan, Cosopt PF) should be requested from the prescribing ophthalmologist to reduce cumulative ocular surface toxicity.
Rigid gas-permeable lens wearers: same 15-minute waiting protocol applies. Prostaglandin-induced periocular changes (fat atrophy, eyelash growth) may alter lens fit — review at subsequent contact lens assessments.

Monitoring and red-flag referral

All glaucoma patients: IOP review 4–6 weeks after any medication change; visual field and optic disc assessment at least annually (more frequently in progressive disease). Ensure ongoing ophthalmologist follow-up is maintained — do not substitute optometric review for specialist management.
Beta-blocker users: Ask about bradycardia, breathlessness, fatigue, or worsening asthma at every review. Nasolacrimal occlusion technique should be verified and reinforced at each visit. Report new cardiac or pulmonary symptoms to the prescribing doctor.
Brimonidine users: Ask about ocular redness, itching, and follicles (signs of drug allergy, which occurs in up to 25% of patients with prolonged use). Alert ophthalmologist if allergy suspected — medication switch required.
Prostaglandin users: Counsel on expected iris and periocular pigmentation changes; advise unilateral users of potential asymmetry. Eyelash growth and periorbital fat atrophy are expected cosmetic effects — not a reason to stop therapy without ophthalmologist guidance.
Red flags requiring same-day emergency referral: Sudden severe eye pain, nausea/vomiting, haloes around lights, corneal clouding, fixed mid-dilated pupil — these are signs of acute angle-closure glaucoma. Refer immediately to the nearest ophthalmic emergency service without delay.

Common glaucoma eye drops in Singapore

All agents listed are, or have been, registered with HSA Singapore or are available through registered importers. Verify current product registration at hsa.gov.sg before referring for any specific product. All agents are POM — Singapore optometrists must refer for prescribing.

Brand (Generic)	Mechanism	Dosing	Min. Age	Side Effects	Clinical Notes
Xalatan Latanoprost 0.005% POM	Prostaglandin F2α analogue — increases uveoscleral outflow	1 drop OD at bedtime	Adults; paediatric use with specialist supervision	Iris/periocular pigmentation, eyelash growth, conjunctival hyperaemia	First-line for POAG and OHT; store unopened bottles refrigerated (2–8°C)
Lumigan Bimatoprost 0.01% POM	Prostamide analogue — increases uveoscleral and trabecular outflow	1 drop OD at bedtime	Adults	Conjunctival hyperaemia, eyelash changes, iris pigmentation, periorbital fat atrophy	0.01% formulation reduces hyperaemia vs. 0.03%; potent IOP lowering (~30–33%)
Travatan C Travoprost 0.004% POM	Prostaglandin F2α analogue — increases uveoscleral outflow	1 drop OD at bedtime	Adults	Conjunctival hyperaemia, iris pigmentation, eyelash growth, stinging	Contains Polyquad preservative — less ocular surface toxicity than BAK; PGA alternative for BAK-sensitive patients
Timoptol Timolol Maleate 0.5% POM	Non-selective beta-blocker — reduces aqueous humour production	1 drop BD	Adults; avoid in children <1 year	Bradycardia, bronchospasm, fatigue, dry eye; contraindicated in asthma, COPD, heart block	Adjunct to PGA or second-line monotherapy; nasolacrimal occlusion mandatory to reduce systemic absorption
Trusopt Dorzolamide 2% POM	Carbonic anhydrase inhibitor (CAI) — reduces aqueous humour secretion	1 drop TID (monotherapy) or BD (adjunct)	Adults; use with caution in children	Stinging/burning, bitter taste, transient blurring; avoid in sulphonamide allergy or severe renal impairment	Additive with beta-blockers; available as fixed combination (Cosopt); well-studied adjunct
Azopt Brinzolamide 1% suspension POM	Carbonic anhydrase inhibitor (CAI) — reduces aqueous humour secretion	1 drop BD–TID; shake well before use	Adults	Transient blurring (suspension), bitter taste, stinging; avoid in sulphonamide allergy	Better tolerated than dorzolamide (less stinging); shake before use; avoid in severe renal impairment
Alphagan P Brimonidine Tartrate 0.1% POM	Selective α2-adrenergic agonist — reduces aqueous production + increases uveoscleral outflow	1 drop BD–TID	≥2 years (extreme caution <2 years — CNS depression risk)	Follicular conjunctivitis/allergy (up to 25%), dry mouth, drowsiness; CNS depression in infants	Favoured in NTG for potential neuroprotective effect; high allergy rate with prolonged use
Cosopt Dorzolamide 2% + Timolol 0.5% POM	CAI + beta-blocker fixed combination — dual-mechanism IOP reduction	1 drop BD	Adults	Combined dorzolamide + timolol effects; stinging, bradycardia, bronchospasm	Improves compliance vs. separate drops; preservative-free Cosopt PF available
DuoTrav Travoprost 0.004% + Timolol 0.5% POM	PGA + beta-blocker fixed combination — uveoscleral outflow + reduced aqueous production	1 drop OD at bedtime	Adults	Combined travoprost + timolol effects; hyperaemia, bradycardia, bronchospasm	Potent IOP reduction; once-daily dosing for patients inadequately controlled on monotherapy
Ganfort Bimatoprost 0.03% + Timolol 0.5% POM	Prostamide + beta-blocker fixed combination — dual-mechanism IOP reduction	1 drop OD at bedtime	Adults	Conjunctival hyperaemia, eyelash changes, bradycardia, bronchospasm	Additive IOP lowering (~35%); once-daily fixed combination; avoid in reactive airways disease

Legend

POMPrescription Only Medicine — Sold or supplied to the public on prescription only.

PPharmacy Medicine — Sold or supplied from any licensed retail pharmacy under pharmacist supervision.

OTCGeneral Sales List (GSL) — Sold or supplied to the public without restriction.

Dosing reflects standard adult doses unless noted. Always refer to the approved product insert for full prescribing information. OD = once daily, BD = twice daily, TID = three times daily, PGA = prostaglandin analogue, CAI = carbonic anhydrase inhibitor. All agents in this class are POM in Singapore.

References

[1] Heijl A, Leske MC, Bengtsson B, et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch Ophthalmol. 2002;120(10):1268–1279. PMID: 12365904.
[2] Tham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121(11):2081–2090. PMID: 24974815.
[3] Shen SY, Wong TY, Foster PJ, et al. The prevalence and types of glaucoma in Malay people: the Singapore Malay Eye Study. Invest Ophthalmol Vis Sci. 2008;49(9):3846–3851. PMID: 18450596.
[4] Health Sciences Authority Singapore. Medicines Act (Cap. 176). Singapore Statutes Online. Available at: sso.agc.gov.sg (accessed March 2026).
[5] Republic of Singapore. Optometrists and Opticians Act 2007 (No. 16 of 2007). Singapore Statutes Online. Available at: sso.agc.gov.sg/Act/OOA2007 (accessed March 2026).
[6] Optometrists and Opticians Board Singapore. Scope of practice guidelines. Ministry of Health Singapore. Available at: moh.gov.sg (accessed March 2026).
[7] Gazzard G, Konstantakopoulou E, Garway-Heath D, et al. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. Lancet. 2019;393(10180):1505–1516. PMID: 30862377.
[8] European Glaucoma Society. Terminology and Guidelines for Glaucoma. 5th ed. PubliComm; 2021. Available at: eugs.org.
[9] Kass MA, Heuer DK, Higginbotham EJ, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120(6):701–713. PMID: 12049574.
[10] Aung T, Nolan WP, Machin D, et al. Anterior chamber depth and the risk of primary angle closure in 2 East Asian populations. Arch Ophthalmol. 2005;123(4):527–532. PMID: 15824229.
[11] Leske MC, Heijl A, Hyman L, et al. Predictors of long-term progression in the early manifest glaucoma trial. Ophthalmology. 2007;114(11):1965–1972. PMID: 17533021.

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