Drugs Used in Ophthalmology: Dyes, Mydriatics, Antibiotics and Steroids

Ophthalmology · Ocular pharmacology · Clinical medicine study notes

Drugs Used in Ophthalmology: Dyes, Mydriatics, Antibiotics, Steroids and Other Medicines

Drugs used in ophthalmology help clinicians examine the eye, treat infection and inflammation, control intraocular pressure, protect the ocular surface and manage selected retinal diseases. Their effects depend on the active ingredient, concentration, formulation, route and condition being treated. Two bottles that both say “eye drops” may have completely different actions.

This lesson develops the curriculum topics of dyes, mydriatics, antibiotics and steroids, then connects them with cycloplegics, glaucoma medicines, antivirals, antifungals, local anaesthetics, allergy medicines, lubricants and specialist preparations. Learn each medicine by asking: what does it do, why is it being used, what can go wrong, and how will its effect be reviewed?

Learning objectives

• Classify ophthalmic medicines by their principal purpose and route.
• Explain mydriasis, cycloplegia and miosis.
• Connect representative drugs with their mechanism, indication and important adverse effects.
• Distinguish surface infection from conditions requiring systemic or specialist treatment.
• Demonstrate safe eye-drop administration and interpret common concentration labels.
• Identify situations in which empirical drops should give way to urgent eye assessment.

These notes support clinical learning. Actual selection, dose, duration and referral follow the examination, current Uganda treatment guidance, the available product information and the supervising eye team’s protocol. Formulations listed here are examples; they do not establish local availability or interchangeability.

1. Classification of Ophthalmic Drugs

A drug may have more than one role. Atropine can assist cycloplegic assessment, support selected uveitis care or be prescribed for amblyopia penalisation. The indication determines how it is used. Memorising only the name misses this clinical distinction.

2. Routes, Formulations and Ocular Drug Delivery

Topical preparations

Solutions contain dissolved drug. Suspensions contain dispersed particles and require shaking when the label specifies it. Gels and ointments remain on the surface longer but can temporarily blur vision. An ophthalmic preparation must be suitable for the eye; a skin cream, ear drop or non-sterile homemade solution is not an equivalent substitute.

Why a topical medicine can have systemic effects

Some of an instilled medicine remains on the surface, some penetrates ocular tissues, and some drains through the lacrimal system. Absorption outside the eye can produce systemic effects. This explains why an ophthalmic beta blocker matters in a patient with asthma and why an antimuscarinic drop can affect a small child beyond the eye. Increasing the number of drops does not simply increase useful treatment: overflow, tearing and exposure also increase.

Specialist and systemic routes

• Periocular administration: selected injections around the eye allow a specialist to deliver treatment near the intended tissue.
• Intracameral administration: delivery into the anterior chamber, commonly in a defined surgical setting.
• Intravitreal administration: delivery into the vitreous cavity for selected retinal, inflammatory or infectious conditions.
• Oral or intravenous therapy: used when the diagnosis requires systemic treatment or topical delivery cannot adequately treat the affected site.

These routes are not interchangeable. A sterile bottle intended for surface use is not automatically safe inside the eye. Injectable preparations need route-specific concentration, composition and handling. Intraocular injections belong within a specialist service.

3. Diagnostic Dyes Used in Ophthalmology

Fluorescein sodium

Fluorescein helps visualise selected surface abnormalities under appropriate blue illumination. An epithelial defect takes up the dye, making its extent easier to see. Common clinical applications include assessment of abrasions and corneal staining, tear-film evaluation, applanation tonometry and selected contact-lens assessments. Record the pattern and location of staining rather than simply writing “fluorescein positive”.

A dendritic pattern raises a different diagnostic question from diffuse punctate staining or a focal defect with an infiltrate. The dye highlights a finding; the history and examination establish its significance. A leakage test may demonstrate aqueous escaping from a wound, but obvious or suspected open-globe injury requires protection and urgent referral rather than repeated manipulation.

For a sterile strip, use the product’s specified moistening method and avoid contaminating the impregnated tip. Do not use an already opened or damaged single-use strip. Remove contact lenses as appropriate for the examination and the product used. The manufacturer’s strip instructions describe handling of that formulation.

Lissamine green and rose bengal

These ocular-surface dyes help demonstrate compromised surface cells and areas with inadequate protective tear-film coverage. They can support assessment of dry-eye and ocular-surface disease. Their staining is interpreted alongside symptoms, tear tests and lid examination. Lissamine green is generally better tolerated than rose bengal; a comparative clinical study found similar usefulness for dry-eye surface staining with better patient tolerance.

Surgical and angiographic dyes

Trypan blue has a specialist surgical role: an appropriate intraocular preparation helps delineate the anterior lens capsule during cataract surgery. Intravenous fluorescein is used for diagnostic vascular imaging of the eye. It is a different preparation and route from a surface strip. Intravenous fluorescein can cause nausea and hypersensitivity, including severe anaphylaxis, so angiography needs screening, trained staff and emergency readiness.

4. Mydriatics and Cycloplegics

Definitions and mechanism

Mydriasis means pupil dilation. Cycloplegia means relaxation or paralysis of accommodation through action on the ciliary muscle. Antimuscarinic agents inhibit parasympathetic effects on the iris sphincter and ciliary muscle; they can cause both effects. Phenylephrine stimulates the iris dilator through adrenergic action and dilates the pupil without providing adequate cycloplegia for a cycloplegic refraction.

Tropicamide

The labelled onset is approximately 15–30 minutes, with activity usually lasting several hours; recovery varies. Explain temporary photophobia and near blur. A dilated pupil alone does not prove that accommodation is fully relaxed. Check the intended examination, previous reactions and suitability for dilation. Its short duration is convenient for a fundus examination, but convenience should not determine a child’s refraction protocol.

Cyclopentolate and atropine

Cyclopentolate produces stronger useful cycloplegia than a weak diagnostic dilation regimen. Children are especially susceptible to systemic reactions such as altered behaviour, confusion and other central nervous system effects. Atropine is more prolonged and may cause dry mouth, flushing, tachycardia and anticholinergic toxicity. A caregiver must understand which eye receives it, how often, for how long and when to seek help.

In anterior uveitis, a prescribed cycloplegic can relieve ciliary spasm and help prevent or manage posterior synechiae. It supports management of a diagnosed condition; it does not replace anti-inflammatory assessment. In amblyopia, atropine penalisation of the better-seeing eye is a separate specialist regimen requiring visual-development monitoring.

Phenylephrine precautions

The 10% label contraindicates use in hypertension, thyrotoxicosis and infants under one year. Serious cardiovascular reactions have been reported, particularly with the stronger formulation. Review cardiovascular disease and interacting medicines; follow the service’s concentration and monitoring policy. Do not apply a statement about the 10% formulation indiscriminately to every formulation, or assume that 2.5% is risk-free.

Angle-closure risk and patient counselling

Pupil dilation can precipitate angle closure in a susceptible eye. Follow an appropriate dilation assessment, particularly where narrow or occludable angles are suspected. Severe pain, headache, halos, vomiting or marked visual deterioration after dilation needs urgent evaluation. Warn the patient that blur and light sensitivity may interfere with driving or work until vision has recovered.

5. Antibiotics Used in Ophthalmology

Choose the diagnosis before the antibiotic

Antibiotics target bacteria. They do not directly treat an allergic response or a viral infection. Determine whether the problem involves the conjunctiva, lid margin, cornea, orbit or intraocular tissues. A surface preparation that is useful in uncomplicated conjunctivitis cannot be assumed to treat orbital cellulitis or endophthalmitis. Corneal infection threatens vision and often requires urgent sampling, intensive treatment and close specialist review.

Chloramphenicol

Its established surface use does not make it suitable for every infection. Rare serious blood dyscrasias, including aplastic anaemia, have been reported after topical use. Product information includes contraindications concerning a personal or family history of blood dyscrasias. Avoid repeated unsupervised courses and review a case that persists, recurs or develops pain or reduced vision. Concentration, age restrictions, storage and duration must follow the available product and clinical protocol.

Tobramycin and gentamicin

These aminoglycosides are useful against selected susceptible organisms. Tobramycin ophthalmic solution is commonly supplied as 0.3%. Local irritation, lid swelling or hypersensitivity may be confused with persistence of the original condition. Treatment review should consider both inadequate antimicrobial effect and a drug reaction; simply adding more drops may worsen a toxic surface.

Ciprofloxacin and other fluoroquinolones

Ciprofloxacin 0.3% has labelled roles in susceptible bacterial conjunctivitis and corneal ulcers. The ulcer regimen differs markedly from routine conjunctivitis treatment. A white crystalline corneal deposit can occur during ciprofloxacin therapy; it needs interpretation in the clinical context. Do not decide that an ulcer is healing from a reduction in discharge alone: visual acuity, defect size, infiltrate and anterior-chamber reaction matter.

Situations requiring more than routine surface drops

• A painful red eye with photophobia, reduced vision or a corneal opacity.
• A contact-lens wearer with pain or suspected keratitis.
• Hyperacute purulent conjunctivitis or neonatal eye infection.
• Proptosis, painful or restricted eye movements, fever or suspected orbital infection.
• Severe inflammation after eye surgery or injection, suggesting possible intraocular infection.

Refer urgently and follow the relevant infection protocol. Do not let an empirical topical prescription substitute for assessment of these conditions.

6. Antiviral and Antifungal Medicines

Acyclovir and ganciclovir

Acyclovir 3% ophthalmic ointment is a nucleoside analogue used for acute herpetic keratitis with dendritic ulcers. It interferes with viral DNA synthesis after activation in infected cells. Use the ophthalmic formulation; a skin preparation is not a replacement. Stinging, punctate keratitis and other local reactions are possible.

Ganciclovir 0.15% ophthalmic gel also has a role in acute herpetic keratitis. It must be distinguished from systemic or intravitreal ganciclovir regimens used for other diagnoses, including selected CMV disease. A shared drug name does not imply a shared route, dose or target disease. HSV epithelial disease, stromal disease and uveitis need different plans; steroids have a carefully controlled specialist role in some deeper inflammatory presentations and can worsen untreated epithelial infection.

Natamycin

Natamycin 5% ophthalmic suspension is an antifungal for susceptible fungal surface infections, including keratitis. Its polyene action affects fungal membrane sterols. Fungal keratitis should be considered after vegetative trauma, but the appearance and history alone are not sufficient to identify an organism. Corneal scraping and response assessment support specialist decisions. Shake the suspension as directed, avoid contamination and do not inject a topical bottle.

Other antifungals

Amphotericin B and azole agents such as voriconazole have selected ophthalmic roles, depending on the organism, location and evidence. Some preparations require pharmacy compounding or systemic therapy. These are organism-directed specialist treatments, not additions to every persistent red eye. Lack of improvement needs reassessment of the diagnosis and susceptibility, rather than continued blind switching between antibiotic and antifungal drops.

7. Corticosteroids Used in Ophthalmology

Mechanism and clinical uses

Corticosteroids reduce inflammatory gene activity and the production or action of inflammatory mediators. Ophthalmic examples include prednisolone acetate, dexamethasone, fluorometholone, loteprednol and difluprednate. They are not interchangeable merely because all are steroids; penetration, formulation, potency and indication differ.

Appropriate uses include selected postoperative inflammation, non-infectious anterior uveitis and other inflammatory conditions diagnosed by the eye team. Topical, periocular, intraocular and systemic steroid treatment have different risks and monitoring needs. The route should match the tissue involved and the specialist plan.

Prednisolone acetate

A common preparation is 1% suspension. Shake it as specified so the delivered medicine is evenly dispersed. Examination before prescribing should include assessment of the cornea; slit-lamp examination and fluorescein are important where indicated. Treatment frequency and taper depend on the severity, response and diagnosis. An old prescription should not be restarted for a new red eye without assessment.

Major adverse effects and monitoring

• Raised intraocular pressure: can produce steroid-induced glaucoma and optic-nerve damage.
• Posterior subcapsular cataract: an important risk with prolonged exposure.
• Infection: inflammation may be masked while bacterial, fungal or viral disease worsens.
• Delayed healing and tissue damage: thinning can increase perforation risk in an already compromised cornea or sclera.

Monitor response and pressure according to the course. The prednisolone acetate label specifically calls for routine pressure monitoring when treatment lasts ten days or longer. A “milder” steroid still needs appropriate follow-up; its name does not remove these responsibilities.

Tapering and patient education

A taper is linked to control of the inflammatory disease and the risk of rebound, not to a fixed timetable for every patient. Give the patient an understandable schedule and review date. Distinguish the anti-inflammatory bottle from the pressure-lowering or antimicrobial bottle if several are prescribed. Persistent pain or visual deterioration requires reassessment even if redness has improved.

8. Non-Steroidal Anti-Inflammatory and Anti-Allergy Drugs

Topical NSAIDs

Ketorolac and other ophthalmic NSAIDs inhibit cyclo-oxygenase pathways and reduce prostaglandin-mediated effects. Selected uses include postoperative inflammation, specific postoperative pain regimens and surgical prevention of miosis, depending on the medicine and formulation. They do not provide antimicrobial treatment.

Possible problems include stinging, delayed healing, bleeding-related concerns and serious corneal complications such as epithelial breakdown, thinning or perforation. Aspirin/NSAID sensitivity and a compromised ocular surface matter. The indication and duration must follow the actual product: two ketorolac concentrations may have different labelled regimens. “Non-steroidal” does not mean that unrestricted use is harmless.

Antihistamines and mast-cell stabilisers

Histamine contributes to the itching and vascular response of allergy. Olopatadine combines H1-receptor antagonism with inhibition of mast-cell histamine release. Ketotifen has a related anti-allergy role, while sodium cromoglicate chiefly stabilises mast cells. These medicines address allergy; they do not establish that every itchy or red eye is allergic.

Choose the product-specific concentration and frequency. Persistent pain, photophobia, unilateral marked redness or visual loss should prompt reconsideration of the diagnosis. Lubrication, avoidance of an identified trigger and lid or surface care may support an allergy plan. Severe vernal or atopic disease with corneal involvement needs specialist assessment rather than prolonged unsupervised steroid treatment.

9. Drugs That Lower Intraocular Pressure

Understanding the target

Aqueous humour is produced by the ciliary body and drains through outflow pathways. Pressure-lowering medicines mainly decrease production, increase outflow, or do both. Lower pressure is a treatment target; preserving the optic nerve and visual function is the clinical goal. Pressure, optic-disc assessment and fields must therefore be interpreted together.

Latanoprost

Latanoprost 0.005% is commonly used in open-angle glaucoma or ocular hypertension. Its labelled schedule is one drop in the affected eye once daily in the evening; increasing frequency is not a simple route to greater benefit. Discuss gradual iris pigmentation, lid-skin darkening and eyelash changes. Iris colour change may be permanent. Check the actual product’s storage and contact-lens instructions.

Timolol

Timolol is a non-selective beta blocker, commonly supplied as 0.25% or 0.5%. Although applied to the eye, it can be absorbed systemically. Labelled contraindications include asthma or its history, severe COPD, sinus bradycardia, second- or third-degree atrioventricular block, overt cardiac failure and cardiogenic shock. Review pulse, respiratory history and interacting cardiac medicines. Ask about tablets as well as eye drops: combined beta-blocking effects can matter.

Dorzolamide and brimonidine

Dorzolamide is a topical carbonic anhydrase inhibitor. Check hypersensitivity and renal function; its label does not recommend use in severe renal impairment. Brimonidine is an alpha-2 agonist that can cause allergic conjunctivitis and systemic drowsiness. It is contraindicated in children younger than two years in the cited label; older children also need specialist caution because sedation can be substantial. Do not choose a glaucoma drop for a child by borrowing an adult regimen.

Pilocarpine and acute angle closure

Pilocarpine causes miosis, or pupil constriction, and has selected pressure-lowering and procedural roles. It can produce brow ache, induced myopic blur and poor dim-light vision; rare retinal detachment is a labelled concern. In acute angle closure, its role and timing depend on the mechanism and initial pressure reduction. Severe pressure elevation can impair iris responsiveness. Do not use repeated pilocarpine blindly in every acute painful eye; urgent specialist treatment and definitive relief of the obstructed mechanism are essential.

Acetazolamide and osmotic treatment

Acetazolamide may be prescribed systemically for selected urgent pressure reduction or other glaucoma situations. Paresthesia, electrolyte loss and metabolic acidosis are important. Marked renal or liver disease, depressed sodium or potassium and other label contraindications require review; monitoring can include renal function, electrolytes and blood counts as appropriate. Intravenous mannitol is an additional hospital-based option in selected pressure emergencies, with fluid, cardiac and renal considerations. Neither medicine replaces definitive management of angle closure.

Adherence and combinations

A fixed combination may simplify treatment, but it retains the risks of every ingredient. For example, a combination containing timolol still requires respiratory and cardiac screening. Ask the patient to show the bottles and demonstrate administration. A high pressure result can reflect poor technique, an exhausted bottle, missed doses, side effects or inadequate efficacy; distinguish these before changing the regimen.

10. Local Anaesthetics, Lubricants and Specialist Medicines

Topical local anaesthetics

Proparacaine, commonly 0.5%, and tetracaine provide short-lived ocular-surface anaesthesia for appropriate procedures such as tonometry and selected foreign-body assessments. They block nerve conduction and remove sensation temporarily; they do not heal the cause of pain. Protect the anaesthetised surface from rubbing or injury. Repeated or prolonged use can cause severe corneal damage, and product information warns of permanent corneal opacity and visual loss. They are procedural medicines, not unrestricted take-home pain treatment.

Artificial tears and lubricating ointments

Examples include carboxymethylcellulose, hypromellose and other tear substitutes. They improve surface lubrication and can relieve selected dryness-related symptoms. More viscous preparations last longer but may blur vision; an ointment is often more practical when blur will interfere less with the patient’s activities. The choice depends on symptoms, examination, frequency required and tolerability.

Preservative-free formulations can be useful when frequent administration or sensitivity makes preservative exposure troublesome. Single-use packaging must be used and discarded as directed. Persistent dryness also needs assessment of lid disease, exposure, medication effects and other causes. Lubricants cannot substitute for antimicrobial therapy in an ulcer or pressure reduction in glaucoma.

Specialist therapies and surgical preparations

• Ocular-surface immunomodulators: selected agents such as ciclosporin are used for particular inflammatory dry-eye conditions after assessment.
• Anti-VEGF treatment: specialist intravitreal medicines address selected neovascular and retinal oedema conditions. They require diagnosis, consent, sterile delivery and scheduled review.
• Ocular antisepsis: an appropriate povidone-iodine protocol is used in procedural care; skin disinfectant concentration and handling must not be casually transferred to the ocular surface.
• Intraocular irrigating solutions and viscoelastics: maintain or protect structures during surgery. Ordinary saline or a topical bottle is not automatically an intraocular substitute.

The examination answer should identify the category and purpose without suggesting that these agents can be administered outside the appropriate service.

11. Safe Administration of Eye Drops and Ointments

1. Confirm the order: patient, medicine, strength, route, correct eye, frequency and duration. Check allergies and expiry.
2. Prepare: wash hands, inspect the container and shake a suspension if its label requires it. Remove contact lenses when instructed.
3. Position: ask the patient to look upwards and gently pull the lower lid down to create a conjunctival pocket.
4. Instil: place the prescribed drop into the pocket without touching the bottle tip to the eye, lashes, skin or fingers.
5. Close gently: avoid forceful squeezing. Gentle pressure over the inner canthus, without pressing the globe, helps reduce drainage through the lacrimal system. Follow the medicine-specific instruction for duration.
6. Space different medicines: generally allow at least five minutes, or the product’s specified interval, to reduce washout. Put drops before ointment when both are prescribed.
7. Finish: replace the cap, remove excess liquid from the surrounding skin and record administration as required.

For ointment, place the prescribed ribbon into the lower conjunctival pocket without contacting the tube tip with the eye. Warn about temporary blur. Ask the patient to demonstrate the technique: understanding the words does not guarantee that the medicine reaches the eye.

Opening dates, storage and contamination

Record the opening date and follow the product’s discard interval; not every container has the same after-opening life. Refrigeration, protection from light and room-temperature limits vary. Do not share bottles or keep using a contaminated tip. Check whether a caregiver can manage the bottle and whether the written schedule is understandable. A clear plan includes what to do if doses are missed and whom to contact for an adverse reaction.

12. Reading Concentrations and Writing a Clear Prescription

For a percentage weight/volume preparation, 1% means 1 g in 100 mL, or 10 mg/mL. Thus 0.5% equals 5 mg/mL, 0.3% equals 3 mg/mL and 0.005% equals 0.05 mg/mL. Confirm what the label expresses: not all percentage conventions are identical, and the salt or active-moiety statement may matter.

Concentration is not the whole dose. The prescription also specifies the amount per administration, treated eye, frequency, duration and changes over time. Drop volume varies with the bottle and technique; do not assume a universal number of drops per millilitre when exact dosing matters.

Special populations and interactions

Children, frail older people, pregnant or breastfeeding patients and people with renal, hepatic, cardiac or respiratory disease need medicine-specific assessment. Review all current medicines, including other eye drops, over-the-counter products and herbal preparations. A topical route reduces some exposure but does not remove interactions or systemic adverse effects. Read the actual label instead of relying on a bottle-cap colour; colour conventions vary across suppliers and settings.

13. Clinical Reasoning and Examination Examples

When urgent assessment takes priority

Sudden visual loss, severe pain, photophobia, a corneal opacity, chemical exposure, penetrating trauma, proptosis or severe symptoms after surgery require urgent assessment. Chemical exposure needs immediate irrigation according to the emergency protocol; a search for the ideal eye-drop bottle must not delay it. In suspected globe rupture, protect without pressure and avoid unnecessary topical instillation or manipulation.

14. Key Points for Revision

• Learn a medicine as class → mechanism → indication → adverse effects → monitoring.
• Mydriasis is dilation; cycloplegia is loss of accommodation; miosis is constriction.
• Diagnostic dyes reveal findings; they do not treat the underlying cause.
• Antibiotics, antivirals and antifungals target different organisms and are not interchangeable.
• Ophthalmic steroids require a diagnosis, review and pressure monitoring when indicated.
• A topical medicine can still cause systemic toxicity or interact with tablets.
• Glaucoma treatment protects visual function through an individualised pressure-lowering plan.
• Proper formulation, laterality, administration and follow-up are part of treatment, not optional extras.

References and Further Reading

The supplied slides guided topic coverage. Medicine-specific precautions were checked against product information; product labels from another jurisdiction do not replace Uganda treatment protocols.

• Supplied SlideShare: Eye drugs and Drugs in ophthalmology.
• Community Eye Health Journal: How to use your eye medication and How to instil eye drops.
• Emergency management of angle-closure glaucoma; Herpes simplex infection of the eye; The red eye at primary level.
• Dexamethasone ophthalmic product information.
• Tropicamide, cyclopentolate, atropine and phenylephrine product information.
• Chloramphenicol SmPC; tobramycin; ciprofloxacin.
• Acyclovir ophthalmic ointment; ganciclovir ophthalmic gel; natamycin.
• Prednisolone acetate; ketorolac; olopatadine.
• Latanoprost; timolol; dorzolamide; brimonidine; pilocarpine; acetazolamide.
• Proparacaine; carboxymethylcellulose lubricant.
• Trypan blue; intravenous fluorescein; comparative lissamine-green and rose-bengal study.

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