NSAID Eye Drops

Concise summaries of topical non-steroidal anti-inflammatory eye drops used in optometric and ophthalmic practice in Singapore, including practical guidance on pharmacology, dosing, patient selection, post-operative applications, and monitoring.

Last updated: March 2026

What are NSAID eye drops?

Topical ocular non-steroidal anti-inflammatory drugs (NSAIDs) are ophthalmic preparations that inhibit the cyclooxygenase (COX) enzyme pathway, reducing the synthesis of prostaglandins, thromboxanes, and prostacyclins at the ocular surface and within intraocular tissues. Unlike corticosteroids, topical NSAIDs achieve clinically significant anti-inflammatory and analgesic effects without the associated risks of raised intraocular pressure (IOP), posterior subcapsular cataract formation, or predisposition to secondary ocular infection.

In Singapore, topical NSAIDs are predominantly used in the perioperative management of cataract surgery — one of the most commonly performed surgical procedures at public eye centres and private ophthalmic clinics. They are also used for post-refractive surgery pain, post-traumatic ocular pain, and cystoid macular oedema (CMO) prophylaxis in at-risk patients. All topical NSAIDs are Prescription-Only Medicines (POM) in Singapore under the HSA Medicines Act (Cap. 176) — optometrists encountering patients who require these agents must refer to an ophthalmologist.^[1,2]

Drug classes

Non-selective COX-1/COX-2 inhibitors — inhibit both isoforms of cyclooxygenase, broadly reducing prostaglandin synthesis; the majority of topical ophthalmic NSAIDs belong to this class (e.g., ketorolac, diclofenac, bromfenac).
Prodrug NSAIDs — inactive parent compounds (e.g., nepafenac) that are converted to active metabolites (amfenac) by intraocular enzymes, enabling superior penetration through the cornea into aqueous humour and posterior segment tissues; particularly useful for CMO prophylaxis.

Who are they for?

Topical NSAIDs are indicated for patients requiring perioperative ocular anti-inflammatory cover, post-traumatic ocular pain management, or prophylaxis against cystoid macular oedema. In Singapore, the high volume of cataract surgery performed at public restructured hospitals and private specialist eye clinics means topical NSAIDs feature in a significant proportion of perioperative medication regimens. Singapore optometrists managing post-operative patients co-managed with ophthalmologists will encounter patients on these agents and must be able to counsel them appropriately and recognise adverse effects.^[3,4]

Patient profiles and common indications

Post-cataract surgery

Most common indication in Singapore; reduces post-op inflammation, pain, and photophobia; key agent for CMO prophylaxis in at-risk eyes.

Post-refractive surgery (LASIK / PRK)

Used for post-operative pain management after PRK; reduces epithelial healing discomfort; short-course use only.

Cystoid macular oedema (CMO) prophylaxis

High-risk eyes — diabetic retinopathy, uveitis history, epiretinal membrane; prodrug NSAIDs (nepafenac) preferred for posterior segment penetration.

Post-traumatic ocular pain

Corneal abrasions and superficial foreign body removal; short-course NSAID provides analgesic effect; avoid prolonged use due to epithelial toxicity risk.

Intraoperative miosis prevention

Pre-operative NSAID instillation helps maintain mydriasis during cataract surgery by inhibiting prostaglandin-mediated intraoperative miosis.

Allergic conjunctivitis (seasonal, adjunct)

Ketorolac has HSA-registered indication for seasonal allergic conjunctivitis itch relief; rarely used as first-line given dual-action antihistamine efficacy.

Caution — contact lens wearers

Topical NSAIDs are not indicated for routine contact lens-related discomfort and should not be instilled while wearing soft contact lenses. BAK-preserved NSAID formulations adsorb onto soft lens polymers, causing toxic keratopathy. More critically, topical NSAIDs may mask pain that serves as an early warning sign of contact lens-related microbial keratitis — a particular concern in Singapore given the high contact lens wearing population and tropical climate favouring Pseudomonas aeruginosa and Acanthamoeba keratitis. Never use topical NSAIDs to manage contact lens-related pain without first ruling out microbial infection.

When should they be used?

Perioperative use — cataract and refractive surgery

Topical NSAIDs are most commonly initiated in the perioperative period. For cataract surgery, they are typically commenced one to three days pre-operatively to reduce intraoperative prostaglandin release, and continued post-operatively for one to four weeks depending on the agent and the patient's risk profile for CMO. In Singapore, perioperative NSAID protocols vary between institutions; optometrists co-managing post-operative patients should confirm the prescribing ophthalmologist's protocol and not modify NSAID frequency or duration without specialist direction.

CMO prophylaxis — high-risk patients

Patients with diabetes mellitus, uveitis history, epiretinal membrane, or prior CMO are at significantly elevated risk of post-cataract CMO. Prodrug NSAIDs with superior posterior segment penetration (nepafenac 0.1% or 0.3%) are the agents of choice in these patients. Duration is typically extended to four to six weeks post-operatively. Optometrists performing post-operative OCT reviews should identify CMO early and refer promptly if macular thickening is detected.

Acute pain relief and referral thresholds

For post-traumatic corneal pain (e.g., after foreign body removal or corneal abrasion), short-course topical NSAIDs provide meaningful analgesia. Use should be limited to 24–48 hours for abrasions; prolonged use risks delayed epithelial healing and epithelial breakdown. Any patient with corneal pain, photophobia, or reduced vision following contact lens wear must be evaluated for microbial keratitis before considering NSAID analgesia — and referred urgently if infection is suspected. Singapore optometrists do not have prescribing rights for any topical NSAID (all POM) — referral to an ophthalmologist or emergency eye service is mandatory when prescription-strength analgesia or anti-inflammatory therapy is required.

Clinical scenario	Recommended agent	Duration / Action
Post-cataract — routine	Ketorolac QID or diclofenac QID	2–4 weeks post-op; ophthalmologist protocol
Post-cataract — high CMO risk (DM, uveitis)	Nepafenac 0.1% TID or 0.3% OD	4–6 weeks post-op; specialist review
Post-PRK pain	Diclofenac or ketorolac QID	24–72 hours only; not for prolonged use
Corneal abrasion pain	Ketorolac QID — refer to ophthalmologist	24–48 hours maximum; rule out infection first
Contact lens-related ocular pain	Cease lens wear; refer urgently	Do NOT use NSAID before excluding microbial keratitis
Refractory CMO post-operatively	Ophthalmology referral — intravitreal VEGF/steroid	Specialist management; urgent OCT review

Where are they available in Singapore?

All topical ophthalmic NSAIDs registered in Singapore are classified as Prescription-Only Medicines (POM) under the Health Sciences Authority (HSA) Medicines Act (Cap. 176). They may only be supplied to patients on a valid prescription issued by a registered medical practitioner. They are not available OTC or through pharmacy channels without a prescription.

Scope of practice — Singapore optometrists

Under the Optometrists and Opticians Act (Cap. 213A) and the Optometrists and Opticians Board (OOB) regulations, Singapore-registered optometrists are authorised to examine eyes, assess visual function, and prescribe optical appliances. They do not have the authority to prescribe, supply, or administer any therapeutic medication, including topical NSAIDs. Optometrists must refer any patient requiring NSAID therapy — including post-operative patients, those with corneal pain, or those at risk of CMO — to a registered medical practitioner. Post-operative co-management arrangements with ophthalmologists do not confer prescribing rights on optometrists.^[5,6]

Prescription-only (POM): All topical ophthalmic NSAIDs — ketorolac (Acular), diclofenac (Voltaren Ophtha), bromfenac (Yellox), nepafenac (Nevanac, Ilevro) — are POM. Valid prescription from a registered medical practitioner is required for all supply.
Hospital formularies: NSAIDs are standard perioperative items on public hospital formularies. Prescribing and dispensing occurs in-house at eye centres and linked hospital pharmacies following ophthalmologist prescription; patients are typically counselled by the dispensing pharmacist at the point of supply.
Private ophthalmology clinics: Topical NSAIDs are prescribed at private specialist clinics and dispensed by licensed retail pharmacies on valid prescription. Repeat supplies require renewal by the prescribing doctor.
Optometric practices: Optometrists in Singapore may encounter patients using topical NSAIDs as part of a post-operative regimen prescribed by their ophthalmologist. Optometrists should be able to counsel patients on correct use and identify adverse effects, but must not initiate, modify, or extend NSAID prescriptions independently.
HSA product verification: Current registration status for all topical NSAIDs can be confirmed via the HSA product registration portal (hsa.gov.sg). Always verify before recommending or referring for any specific product.^[5]

Why use topical NSAIDs over corticosteroids?

Topical NSAIDs offer clinically meaningful anti-inflammatory and analgesic effects through COX pathway inhibition without engaging the glucocorticoid receptor. This mechanistic difference confers a significantly safer ocular adverse effect profile than corticosteroids for appropriate indications — particularly important in the post-operative context where both drug classes are frequently co-prescribed.

No IOP elevation risk

Unlike steroids, NSAIDs do not raise IOP via trabecular meshwork effects — safe for use in glaucoma suspects and steroid responders.

No cataractogenic risk

Corticosteroids are associated with posterior subcapsular cataract formation with prolonged use; NSAIDs carry no such risk.

Targeted prostaglandin inhibition

Directly inhibits PGE2 and PGF2α — the key mediators of post-surgical inflammation, miosis, pain, and CMO formation.

Synergistic with corticosteroids

NSAIDs and topical steroids act via complementary pathways; combination use post-cataract surgery provides superior CMO prevention over either agent alone.

For severe intraocular inflammation (uveitis, post-surgical flare with significant anterior chamber cells and flare), topical corticosteroids remain more potent and are the agents of choice. NSAIDs are used as adjuncts or for patients where steroid use is contraindicated or carries higher risk. In the management of allergic conjunctivitis, dual-action antihistamine/mast cell stabilisers (olopatadine, ketotifen) are preferred first-line over NSAIDs, which offer modest benefit for ocular itch.^[7,8]

How to use NSAID eye drops — patient instructions

Instillation technique

Wash hands thoroughly with soap and water before handling the bottle or touching the eye area.
Tilt head back slightly and gently pull down the lower eyelid to form a small pocket (lower fornix).
Hold the bottle inverted above the eye and instil one drop into the lower fornix — do not allow the bottle tip to touch the eye, eyelid, or eyelashes to avoid contamination.
Gently close the eye and apply nasolacrimal occlusion (fingertip to the inner corner of the eye) for 1–2 minutes to maximise ocular retention and minimise systemic absorption.
If using more than one type of drop (e.g., NSAID plus topical steroid), wait at least 5 minutes between each preparation to prevent dilution and washout of the first agent.
Recap the bottle immediately after use; store at room temperature away from direct sunlight. Shake suspension formulations (Nevanac, Ilevro) well before each use. Discard bottles within the period stated on the label after first opening — typically 4 weeks for multi-dose bottles.

Contact lens guidance

Do not instil topical NSAIDs while wearing soft contact lenses. BAK-preserved NSAID formulations accumulate on soft lens polymers and can cause toxic keratopathy with repeated exposure.
Contact lens wear is generally contraindicated in the post-operative period — advise patients to cease lens wear for the full duration of their post-operative NSAID and steroid course, unless specifically directed otherwise by their ophthalmologist.
Never use topical NSAIDs to manage ocular pain in an active contact lens wearer without first performing a thorough slit-lamp examination to exclude microbial keratitis. In Singapore, the high CL-wearing population and warm, humid climate confer elevated Pseudomonas aeruginosa and Acanthamoeba risk.
Return to contact lens wear post-operatively should only be on the advice of the treating ophthalmologist — typically not before the ocular surface has fully stabilised and anti-inflammatory therapy has been completed.

Monitoring and red-flag referral

All post-operative patients: Review visual acuity, corneal clarity, and anterior chamber status at scheduled post-op visits. Persistently poor visual acuity at 4–6 weeks warrants OCT macula to exclude CMO.
Corneal integrity: Assess corneal epithelium at each visit — NSAIDs can cause superficial punctate keratitis, epithelial defects, or (rarely) corneal melting, particularly with non-preserved formulations used beyond recommended duration.
NSAID hypersensitivity: Counsel patients with known aspirin or systemic NSAID sensitivity about cross-reactivity risk with topical ophthalmic NSAIDs — refer to prescribing ophthalmologist before initiation.
Red flags requiring urgent ophthalmology referral: Sudden loss or deterioration of vision, increasing photophobia, worsening pain despite NSAID use, corneal infiltrate or ulcer, hypopyon, significant anterior chamber flare, or any suspicion of endophthalmitis following intraocular surgery.

Common NSAID 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 recommending or referring for any specific product.

Brand (Generic)	Mechanism	Dosing	Min. Age	Side Effects	Clinical Notes
Acular Ketorolac tromethamine 0.5% POM	Non-selective COX-1/COX-2 inhibitor — reduces prostaglandin synthesis	1 drop QID; up to 4 weeks post-op	≥3 years	Stinging/burning on instillation, superficial punctate keratitis, corneal infiltrates	Post-op pain and inflammation; CMO prophylaxis after cataract surgery; avoid in aspirin/NSAID allergy
Voltaren Ophtha Diclofenac sodium 0.1% POM	Non-selective COX inhibitor — inhibits prostaglandin and thromboxane synthesis	1 drop QID; commence 24 hours pre-op or immediately post-op	Adults	Stinging, transient blurring, keratitis; corneal melting reported with prolonged use	Post-cataract and refractive surgery inflammation; also used for post-traumatic ocular pain; ophthalmologist prescribing
Nevanac Nepafenac 0.1% suspension POM	Prodrug NSAID — converted to amfenac in ocular tissues; COX-1/COX-2 inhibition	1 drop TID; start 1 day pre-op; up to 2 weeks post cataract surgery	Adults	Stinging/burning, foreign body sensation, decreased visual acuity (suspension)	Prodrug formulation — superior intraocular penetration; shake well before use; used for CMO prevention and post-op pain

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. BD = twice daily, TID = three times daily, QID = four times daily, OD = once daily, PRN = as needed.

References

[1] Flach AJ. Cyclo-oxygenase inhibitors in ophthalmology. Surv Ophthalmol. 1992;36(4):259–284. PMID: 1539583.
[2] Health Sciences Authority Singapore. Medicines Act (Cap. 176). Singapore Statutes Online. Available at: sso.agc.gov.sg (accessed March 2026).
[3] Henderson BA, Kim JY, Ament CS, Ferrufino-Ponce ZK, Grabowska A, Cremers SL. Clinical pseudophakic cystoid macular edema — risk factors for development and duration after treatment. J Cataract Refract Surg. 2007;33(9):1550–1558. PMID: 17720069.
[4] Wielders LHP, Schouten JSAG, Winkens B, et al. European multicenter trial of the prevention of cystoid macular edema after cataract surgery in nondiabetic patients: ESCRS PREMED study report 1. J Cataract Refract Surg. 2018;44(4):429–439. PMID: 29703285.
[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] George PP, Chng OSY, Siow K, et al. Is there scope for expanding the optometrist's scope of practice in Singapore? A survey of optometrists and opticians. Cont Lens Anterior Eye. 2019;42(3):258–264. PMID: 30819628.
[7] Kim SJ, Flach AJ, Jampol LM. Nonsteroidal anti-inflammatory drugs in ophthalmology. Surv Ophthalmol. 2010;55(2):108–133. PMID: 20159228.
[8] Waterbury LD, Silliman D, Jolas T. Comparison of cyclooxygenase inhibitory activity and ocular anti-inflammatory effects of ketorolac tromethamine and bromfenac sodium. Curr Med Res Opin. 2006;22(6):1133–1140. PMID: 16846545.
[9] Bucci FA Jr, Waterbury LD. Aqueous humor amfenac and ketorolac assessment following topical administration of Nevanac and Acular in patients undergoing phacoemulsification. Am J Ophthalmol. 2008;146(6):832–836. PMID: 18723140.
[10] Nardi M. Diclofenac sodium ophthalmic solution in the management of ocular inflammation. Expert Opin Pharmacother. 2005;6(10):1741–1748. PMID: 16086636.

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