Ophthalmic Drugs Viva: Bottles, Colours, Doses and Contraindications

The answer begins with the label, not the cap

In an ophthalmic-drugs viva, a cap colour is a recall cue, not an identification method. Local stocks, manufacturers, combination products and packaging change. Begin with the generic name, concentration, dosage form and route on the label. Then give the class, one mechanism, one examination use or association, and one relevant caution. That sequence is quick enough for a practical station and avoids the classic error of naming a medicine because a bottle resembles one seen in a coaching handout.

The examiner may deliberately cover the brand name, present an unfamiliar manufacturer, or place a fixed-combination bottle beside a single agent. The right response is still the same: inspect what is printed before inferring what the bottle does. A colour code can help you retrieve a class after you have read it; it cannot prove contents, concentration, preservative status or suitability.

This is postgraduate exam education for doctors, not a prescribing chart. Formulation, indication, age group, route, local policy and current product information decide a real dose or contraindication. The purpose here is to make your viva answer precise and to show where verification belongs.

Use the five-part bottle-station answer

When the examiner asks, “What is this?”, do not launch into a catalogue of uses. Give a five-part answer in order.

1. Identify: “This is [generic name], [concentration] ophthalmic [solution/suspension/gel/strip], for [route] use.” State only what the label establishes.
2. Classify: “It is a [pharmacological class].” If the bottle has two actives, name both classes.
3. Mechanise: Give one dominant action. “It reduces aqueous production through beta blockade” is stronger than “it lowers IOP.”
4. Anchor it to the station: State one usual examination association: pupil dilation, cycloplegic refraction, IOP lowering, surface staining or temporary surface anaesthesia.
5. Add one limit: Mention the most relevant adverse effect, contraindication context or label check. Do not turn a caution into an absolute rule when the medicine and clinical setting have not been specified.

That is a complete 20–30 second answer. If asked for more, expand the part the examiner selected rather than adding unrelated pharmacology.

What “dose” means in a viva

“What is the dose?” is not one question. In an exam it may mean the printed strength, the amount in a single application, the labelled frequency for a named indication, a route distinction, or an emergency/theatre protocol. First clarify the drug and formulation. Then answer at the level actually requested.

For a bottle in front of you, start with the visible concentration. If the examiner asks for a labelled regimen, tie the answer to that exact product and indication: “I would verify the current authorised product information for this formulation and indication before stating the regimen.” That is not evasive. It is pharmacologically correct. The current DailyMed drug-label database illustrates why: labels record the specific preparation, indication, warnings and dosage rather than a class-wide recipe.

Do not transpose a topical concentration into a periocular, intracameral, oral or intravitreal answer. Do not assume a preservative-free vial, a gel-forming solution and a standard multidose solution have the same use. Do not turn an old “one drop twice daily” flashcard into a rule. A practical examiner is usually testing whether you recognise this distinction.

A useful verbal template is: “The label shows [strength and form]. For the requested indication, the exact dose must be checked in the current individual monograph and local protocol; the viva-level point is that this agent is [class] and [mechanism].” For revision, store the source beside any dose line in your notes: current product monograph, national formulary or institution’s authorised practical list, plus its access date.

Pupil bottles: separate dilation from cycloplegia

Pupil-drug stations reward receptor logic. Antimuscarinics block muscarinic activity at the iris sphincter and ciliary muscle. Their examination association is mydriasis with cycloplegia. A sympathomimetic such as a phenylephrine-type agent acts through the dilator pathway; its high-yield distinction is mydriasis without cycloplegia. That contrast is more valuable than a brand-name list.

The key caution is contextual. An examiner may ask about cardiovascular effects, angle anatomy, systemic anticholinergic effects, age or interacting medication. The strong answer names the relevant concern and says that the labelled contraindications and precautions are product-specific. A weak answer says “contraindicated in glaucoma” without naming the drug, angle mechanism or context.

The current tropicamide product label is a useful example of why a viva dose must be tied to a named preparation rather than recalled as a universal cycloplegic schedule. Learn the physiological distinction; verify the product-specific line.

IOP-lowering drops: production, outflow and systemic clues

First divide these drugs into aqueous suppressants and outflow-enhancing agents. That makes mechanism questions, adverse-effect stems and combination bottles much easier.

For a beta-blocker bottle, the safest short answer is: “This is a topical aqueous suppressant. I would consider the labelled contraindications and warnings, particularly respiratory and cardiac context, rather than assume topical use avoids systemic beta blockade.” The NCBI Bookshelf timolol review provides background on the mechanism and systemic adverse-effect logic. In a real clinical setting, the individual current label and local supervision govern the decision.

For a prostaglandin analogue, say uveoscleral outflow, then state one recognisable local adverse-effect association. For a carbonic anhydrase inhibitor, say aqueous suppression and immediately distinguish topical from systemic therapy. These details show that you are reasoning from mechanism, not memorising a colour convention.

Fixed combinations are a deliberate viva trap. Read both active ingredients. State both mechanisms, then check whether one component changes the adverse-effect or contraindication discussion. It is inaccurate to identify a combined bottle merely as “timolol” or “a prostaglandin” when the label shows two actives.

Surface, stain and anaesthetic stations

Some items on the table are diagnostic aids, not therapeutic bottles. The question is often about the purpose of the item and the observation method.

Fluorescein: identify it as a dye used in surface-staining and tear-film examination contexts. If asked how to observe it, mention cobalt-blue illumination at the slit lamp. Avoid describing it as an antibiotic, topical anaesthetic or a treatment. A follow-up may explore corneal epithelial defects, tear-film assessment or contact-lens-related staining; answer the specific station question.

Topical anaesthetic: identify the active ingredient and the temporary reduction in corneal sensation. The usual practical association is an examination or procedure setting such as tonometry, after the appropriate supervision and protocol. The high-yield caution is not to present it as a take-home pain-relief shortcut. The current Alcaine (proparacaine) label is a good source to consult for the exact product’s warnings and instructions.

Mydriatic plus anaesthetic combinations: do not assume one bottle contains the other. Read the active ingredients. A sequence used for a local clinic workflow is not a universal examination answer and never substitutes for the station’s written instructions.

Anti-inflammatory and anti-infective bottles: name the risk that belongs to the class

Topical corticosteroid questions often test whether you know the monitoring problem, not whether you can recite a taper. A concise answer is: “This is a corticosteroid with anti-inflammatory action; raised IOP, cataract, delayed epithelial healing and infection-related concerns are relevant class associations, so indication and follow-up are context-specific.” Do not say “use it for every red eye.” That would be unsafe and poor viva reasoning.

NSAID questions test differentiation from corticosteroids. State the prostaglandin-pathway mechanism at a high level, then acknowledge that corneal-surface risk and suitability depend on the setting and current product information. If the bottle is a suspension, read it; formulation is part of the identification, not decoration.

For antimicrobial and antiviral bottles, start with the organism category and tissue context the examiner provides. An antibacterial, antiviral and antifungal are not interchangeable “infection drops.” A correct answer may be as simple as: “This class targets [organism/process]; selection and regimen need diagnosis, the current monograph and local microbiology protocol.” Do not convert an MCQ association into a patient treatment plan.

Contraindication answers: be precise without sounding overconfident

Candidates often lose marks with absolute language. “Contraindicated in glaucoma,” “safe in everyone,” and “no systemic effects because it is topical” are all warning signs. Replace them with a structured response:

1. State the class and the relevant concern.
2. Say whether the issue is a labelled contraindication, warning, interaction, route-specific risk or examination association.
3. Tie any definite statement to the individual current product information.

For example, a beta-blocker cue should make you consider respiratory or cardiac context. A phenylephrine-type cue should make you consider the relevant cardiovascular context. A topical anaesthetic cue should make you recognise supervised procedural use rather than self-directed repeat use. None of those statements replaces the specific label. The NCBI Bookshelf review of glaucoma is helpful background for class mechanisms; it is not a substitute for a current medicine monograph.

In a viva, it is acceptable to say, “I would check the current label before calling that an absolute contraindication.” It demonstrates that contraindications are not a game of word association. The examiner may then ask you to identify the exact component, route or patient factor that changes the answer.

A ten-minute rehearsal that exposes weak links

Build a drug tray deck with a photograph or label transcription on the front and five prompts on the back: generic name and strength; class; mechanism; station association; one caution plus source for any dose line. Cover the answer, give yourself ten seconds to identify and 20 seconds to answer. Then reverse the card: start with “mydriasis without cycloplegia,” “brow ache and miosis,” “bradycardia warning,” or “cobalt-blue observation” and retrieve the class.

Practise with mixed cards. Put a fixed combination beside its components, a staining strip beside an anaesthetic vial, and two dilators with different cycloplegic effects together. Mark errors as label-reading, class, mechanism, caution, or dose-source errors. The next revision session should target the error category, not merely repeat the whole list.

For structured drug-station revision, use the Ophthalmology Drugs Practical PDF. The Instruments & Drugs for Practical Exams/Viva is the relevant combined tray-station resource. For broader practical preparation, see the OSCE, Practical & Viva Voce Ready bundle. These are revision resources, not clinical protocols; verify every live dose and product warning against the current authorised source used by your institution.

Sources and currency boundary

• DailyMed — National Library of Medicine repository of current U.S. structured product labels. Use the individual current label for formulation, indications, contraindications, warnings and labelled dosage.
• DailyMed: Tropicamide — product-specific example for a mydriatic/cycloplegic preparation.
• DailyMed: Alcaine (proparacaine) — product-specific example for topical anaesthetic precautions.
• NCBI Bookshelf: Timolol — pharmacology background for beta-blockade and systemic adverse-effect reasoning.
• NCBI Bookshelf: Phenylephrine — pharmacology background for alpha-adrenergic effects.
• NCBI Bookshelf: Glaucoma — background on aqueous dynamics and IOP-lowering classes.

Source check: external URLs above returned HTTP 200 on 18 August 2026. Labels and local stock change; the publication editor must recheck the individual product monograph and any institution-specific practical list immediately before uploading.