Long Case: Glaucoma — History, Examination and Discussion Points

In a glaucoma long case, do not present an IOP number and wait for the viva. Build a correlation: clinical context and angle → pressure measurement → optic-nerve structure → visual function. Your working diagnosis is credible only when the available evidence fits together and you state the limitations of any test that does not fit.

This is a practical-exam rehearsal guide for postgraduate doctors. It does not diagnose a person, set a target IOP, prescribe drops or procedures, or replace current guidelines, local protocols and supervision.

Use the four-evidence board before you speak

Write four headings on your case sheet. Fill them with the actual findings, not the findings you expect in a textbook case.

The board prevents two errors. First, it stops you calling “glaucoma” because an IOP is high. Second, it stops you calling a visual-field defect “progression” because a printout has coloured sectors. A field, OCT or disc finding has value only in its quality and clinical context.

Start with this bounded one-line summary:

“This is a [age]-year-old patient with [unilateral/bilateral] [known glaucoma/suspect status or relevant finding], with [duration and treatment/adherence context if provided]. IOP by [method] is [value] in the [eye]. The disc shows [specific feature], with [reliable/concordant/limited] field and OCT information. Gonioscopy shows [description if performed]. My working diagnosis is [supported classification], while I would clarify [specific uncertainty] before final staging or progression assessment.”

That final clause matters. A case may support glaucomatous optic neuropathy but not an exact subtype. It may support a diagnosis but not progression. It may have a high IOP with a normal disc. Strong candidates state which level of conclusion the evidence supports.

Take a history that changes classification

Begin with visual symptoms and their tempo, but remember that glaucoma may be asymptomatic until functional loss is advanced. Do not use absence of symptoms as absence of disease. Establish prior diagnosis, previous IOP information if the case provides it, previous fields/OCT/disc records, treatment history, adherence difficulties and adverse-effect history only where relevant to the examination discussion.

Then deliberately screen for branches that alter the differential:

Avoid a list of negatives with no diagnostic function. “No diabetes, no hypertension, no tuberculosis, no asthma…” adds little unless a point changes your current question. A better spoken history is: “There is a history of steroid exposure, which is relevant to a secondary mechanism. There is no trauma or prior uveitis on the available history; I would still rely on the anterior-segment and angle findings rather than exclude a mechanism from history alone.”

Present the examination in a fixed, defensible sequence

Start with visual acuity and correction context. Inspect the eye and anterior segment before the disc, because corneal, chamber, iris, lens and pupil findings may explain or qualify later conclusions. Measure IOP and name the method. Then describe gonioscopy where it has been performed and is relevant. Examine the disc systematically, then interpret fields and OCT with reliability/quality checks. End with the fellow eye.

1. Visual function and anterior segment

State acuity, eye and method. Pupils, cornea, AC depth, iris and lens status are not filler: they locate secondary clues and angle context. If there is pseudoexfoliative material, pigment, corneal change, inflammation, a shallow chamber or a particular lens status, describe it exactly. Do not jump from a finding to a subtype label without the intermediate reasoning.

2. IOP is a measurement, not the diagnosis

Give the method and value. If repeat measurements, asymmetry, diurnal pattern, corneal considerations or treatment context are supplied, place them in the pressure story. Do not say “the IOP is normal, therefore there is no glaucoma,” and do not say “the IOP is raised, therefore this is primary open-angle glaucoma.” The NCBI Bookshelf overview of open-angle glaucoma and EyeWiki primary open-angle glaucoma reference are background sources for disease concepts; neither provides a one-number practical diagnosis.

3. Gonioscopy needs description

“Angle open” is usually too thin for a long case. Use the terminology your programme teaches, then state the features visible: angle configuration, structures seen, pigmentation, peripheral anterior synechiae, recession or other case-specific clues. If gonioscopy was not done, do not invent it. Say: “Angle assessment is a key unresolved part of the classification; I would describe it before assigning an open-angle or angle-closure mechanism.”

4. Describe the optic nerve before interpreting it

Use a stable order: disc size/appearance, cup and rim, focal notching, haemorrhage, RNFL defects, peripapillary changes and inter-eye asymmetry. A cup-to-disc ratio without disc size, rim description or comparison is rarely a full glaucoma answer. In a highly myopic disc or an anomalous disc, acknowledge the interpretive limitation. The goal is not to produce every optic-nerve adjective; it is to name the structural feature that correlates with the rest of the case.

5. Field and OCT: check reliability before correlation

Before you call a field defect, comment on available reliability indices, test quality, learning effect, media opacity and whether the pattern plausibly corresponds to disc/RNFL findings. Before you call an OCT abnormal, check scan quality, segmentation/artefact and anatomic plausibility. A colour-coded classification is an aid, not a diagnosis.

Use a correlation paragraph:

“The [eye] has [rim/notch/RNFL feature]. The field shows [pattern] and the OCT shows [pattern] if the tests are reliable. These are [concordant/not fully concordant]. Because [quality issue, discordance, media problem or alternative explanation], I would [repeat/review/seek the relevant discriminator] before making a final claim about severity or progression.”

This paragraph can be adapted to every glaucoma long case. It is especially useful when the examiner deliberately supplies a poor field, a borderline OCT or a disc whose appearance could be physiological or myopic.

Make classification and differential explicit

Use three levels of conclusion.

1. Observed level: “There is raised IOP by this method,” “the angle appears open on this description,” “there is rim thinning/notching,” “the field is unreliable/reliable.”
2. Syndrome level: “The structural and functional findings are/are not consistent with glaucomatous optic neuropathy.”
3. Subtype level: “Primary open-angle glaucoma is supported only if the full phenotype and exclusion of secondary causes fit; the relevant competing mechanisms are …”

For a differential, identify a real alternative and a discriminator. Physiological cupping, myopic-disc appearance and non-glaucomatous optic neuropathy can be relevant in appropriate cases. Secondary glaucoma requires a specific clue, such as steroid exposure, trauma, inflammation, pigment, pseudoexfoliation or lens/post-surgical context. Do not invoke every subtype from a list if the case does not support it.

Likely viva branches

“How would you stage severity?”

State the principle, not a memorised label: structural and functional evidence are considered together, using the classification convention required by the programme. Do not grade from IOP alone. If the field is unreliable or unavailable, say that severity cannot be confidently assigned from it.

“Is this progressing?”

Progression is a longitudinal claim. Explain that you would compare like with like: reliable serial fields, disc documentation, OCT trend where interpretable, IOP history and the same clinical context. A single test can be abnormal without proving change. This is an exam answer, not a direction for a patient’s care.

“What additional tests do you need?”

Respond with purpose: “I would establish angle anatomy/classification,” “I would confirm field reliability and structure-function correlation,” or “I would investigate a specific secondary or non-glaucomatous concern suggested by the history/examination.” Avoid a shopping list or a universal protocol.

“What would your management be?”

In an education setting, begin with the clinical decision framework rather than a prescription: “Management depends on confirmed diagnosis, severity, rate of change, IOP context, patient factors and current local guidance. I would not select an intervention from the partial case data alone.” The NICE glaucoma guideline NG81 is a current evidence-based guideline reference, but it should not be used here as a substitute for individual clinical assessment.

“What do you examine in the fellow eye?”

Repeat the relevant structure: visual function, anterior segment, IOP, angle when indicated, disc and functional testing. Explain that comparison may reveal asymmetry, bilateral susceptibility or a clue to physiological disc appearance. Do not treat the fellow eye as a token normality statement.

A timed rehearsal routine

Spend five minutes before each practice case completing this card. Then speak for three minutes, answer five rapid questions, and repeat only the section where your reasoning broke.

Common errors are predictable: treating IOP as diagnosis; saying “open angle” without a description; reporting cup/disc without rim or disc-size context; treating a single OCT map as proof; ignoring the fellow eye; and prescribing a treatment when the examiner asked for classification. Each error is fixed by returning to the four-evidence board.

For a broader topic review, use the verified on-site glaucoma study guide and Glaucoma Exam Ready Notes. For practical-station rehearsal, use the OSCE, Practical & Viva Voce Ready bundle, the DNB Ophthalmology preparation guide, and the case-presentation format resource. These are study resources; they do not replace supervised disc, field or gonioscopy interpretation.

Handle conflicting evidence without collapsing the presentation

Practical cases sometimes contain disagreement by design: a suspicious disc with an unreliable field, an OCT flag that does not match the disc, or a raised IOP with no convincing structural damage. Do not hide the contradiction. Name it, identify the possible reason and state the next discriminating question. “The OCT result is not fully concordant with the disc appearance. I would first review scan quality and segmentation, then compare the fellow eye and determine whether a non-glaucomatous explanation is plausible.” That is more useful than choosing whichever result looks most abnormal.

Likewise, separate measurement error from biological variation and disease change. If the case gives a single IOP, its value is a data point. If it gives a serial record, ask whether technique, timing, treatment status and corneal context are comparable before treating a difference as a trend. If it gives serial fields, check whether the tests are comparably reliable. The relevant viva skill is not memorising a fixed interval; it is explaining why longitudinal claims require comparable evidence.

A concise examiner-facing conclusion

End with one structured paragraph: “The angle/anterior-segment context is [X]. Pressure context is [Y]. Structural evidence is [Z], and functional evidence is [A], with [reliability limitation if present]. Together these support [working diagnosis]. The main competing explanation is [B], which I would separate using [C]. I would not yet state [subtype/severity/progression] because [D].”

This conclusion makes your reasoning inspectable. It also prevents the common end-of-case drift into a long treatment list. If the examiner asks what follows, answer their new question. If they do not, stop. A clean conclusion is better than adding unsupported certainty.

Teach a colleague the four-evidence board

Pair practice is especially useful for glaucoma because the listener can challenge a correlation. Give your colleague a disc image, field extract or OCT report and ask them to interrupt with one of four questions: “What makes the field reliable?”, “How does this match the disc?”, “What does the angle add?”, and “What would change your subtype?” Reverse roles. The goal is not to agree on a management plan; it is to make every diagnostic statement traceable to a finding and every uncertainty explicit.

Sources

• NICE, Glaucoma: diagnosis and management (NG81)
• EyeWiki, Primary Open-Angle Glaucoma
• NCBI Bookshelf, Open Angle Glaucoma