Glaucoma remains one of the most important causes of irreversible visual disability in clinical eyecare because it is often asymptomatic until meaningful functional loss has already occurred.
At its core, glaucoma is not simply a disease of elevated intraocular pressure (IOP), but a chronic, progressive optic neuropathy characterized by retinal ganglion cell loss, thinning of the retinal nerve fiber layer, characteristic optic nerve head damage, and corresponding visual field defects.
Why you should brush up on your glaucoma workup
Modern glaucoma diagnosis depends on a comprehensive assessment of the full clinical picture and correlating structure and function rather than relying on any single metric alone.
This is precisely why even experienced clinicians benefit from revisiting a standardized glaucoma workflow: it reduces the chance of anchoring too heavily on IOP, missing angle pathology, overcalling optical coherence tomography (OCT) artifacts, or underappreciating subtle disc and field correlations.1-5
A refresher on glaucoma workup is especially useful in contemporary optometric and ophthalmic practice because the diagnostic landscape has become broader, not simpler. The clinician today must synthesize history, risk profile, tonometry, pachymetry, gonioscopy, optic nerve head assessment, OCT, and perimetry, while also recognizing when adjunctive tests such as 10-2 visual fields, OCT angiography, disc photography, or electrophysiology may add value.
The challenge is not a lack of tests, but knowing the right sequence, understanding what each test contributes, and interpreting the findings in context. A disciplined, stepwise evaluation helps distinguish ocular hypertension from glaucoma, identifies glaucoma suspects who merit close surveillance, and supports early treatment in patients with confirmed structural and functional disease.2-8
Step-by-step guide to glaucoma assessment
A glaucoma workup is not a checklist of investigations performed in isolation. It begins with identifying risk, moves to defining the anatomical mechanism, and is then confirmed through structural assessment and functional testing, making it a structured clinical sequence.
Attain a patient history and risk factors
Every glaucoma workup begins with history, because pretest probability matters. Many glaucomas are asymptomatic until meaningful damage has already occurred, so the absence of symptoms should never lower clinical suspicion too quickly.
A focused history identifies who deserves a deeper workup, helps uncover secondary causes, and highlights factors that may later affect treatment choice or progression risk.2,5 Key risk factors to review include older age, family history of glaucoma, steroid exposure, ocular trauma, uveitis, migraine, sleep apnea, diabetes, refractive error, and race- or ethnicity-related risk patterns.
Family history deserves special attention, but it should be interpreted carefully. Keep in mind that in glaucoma, a “negative” family history may simply mean relatives were never diagnosed. In some patients, vascular history also becomes highly relevant, especially when normal-tension glaucoma or progression out of proportion to IOP is noted.5,6
A concise risk checklist can be helpful in clinic:2,5
- Age
- Family history of glaucoma
- Prior elevated IOP
- Steroid use
- Trauma or intraocular inflammation
- Migraine or vasospastic history
- Sleep apnea
- Diabetes
- Myopia or hyperopia
- Current systemic and ocular medications
Download the flowchart here!
Glaucoma Evaluation and Management Flowchart
Use this flowchart to guide and hone your glaucoma diagnostic and management workflow to identify suspects early and initiate treatment before significant functional vision loss occurs.
Measure IOP
IOP measurement is essential, but it should never stand alone. Goldmann applanation tonometry remains the clinical reference standard, yet the meaning of any pressure reading must be interpreted in the context of the individual patient’s cornea, angle anatomy, optic nerve appearance, OCT findings, and visual field status. Glaucoma cannot be diagnosed from IOP alone, and a “normal” pressure does not rule out disease.2-4
In practice, clinicians should pay attention not only to the absolute reading, but also to inter-eye asymmetry and repeatability. If the pressure looks reassuring but the disc, RNFL, or field does not, trust the whole picture instead of the tonometer. Likewise, a mildly elevated IOP in an otherwise normal eye may reflect ocular hypertension rather than glaucoma.2,4
Evaluate the optic nerve head
Optic nerve head evaluation remains the clinical anchor of glaucoma diagnosis. The disc should be assessed systematically, not impressionistically. That means identifying disc size first, then evaluating the neuroretinal rim, cup contour, RNFL appearance, peripapillary atrophy, and disc hemorrhages. Cup-to-disc ratio alone is not enough, because physiologic cupping varies widely with disc size.1,2
Clinically, the most useful features to document are:
- Disc size
- Focal or diffuse rim thinning
- Notching
- Vertical elongation of the cup
- RNFL wedge defects
- Disc hemorrhages
- Inter-eye asymmetry
Large discs can have large physiologic cups, while small discs can hide significant rim loss without dramatic cupping. Rim quality matters more than a single cup number. Disc hemorrhages matter, too, because they may indicate active or future progression and should always raise the level of concern.6
Attain pachymetry
Central corneal thickness is an independent risk factor for the development and progression of glaucoma and hence pachymetry should be incorporated in the glaucoma workup. Patients with thinner corneas have been shown to have a higher likelihood of glaucomatous damage, while those with thicker corneas tend to have a comparatively lower risk profile.7,8
Although corneal thickness does influence the accuracy of applanation tonometry, its clinical importance lies more in risk stratification than in mathematical correction of intraocular pressure values.7,8
The most practical use of pachymetry is not to apply a rigid correction formula to every patient. It is to understand risk in context. A pressure of 18mmHg in a patient with a very thin cornea and suspicious OCT findings is not the same clinical scenario as 18mmHg in a thick-cornea patient with a healthy disc and normal fields.
The procedure is particularly useful in glaucoma suspects and ocular hypertensive patients because it helps contextualize risk when IOP values do not align with structural or functional findings.7,8
For example, a patient with borderline elevated IOP but a thin cornea and suspicious optic nerve or OCT changes may warrant closer surveillance or earlier intervention, whereas a similar IOP reading in a patient with a thick cornea and normal structural testing may represent lower true risk.
Perform gonioscopy
Gonioscopy is one of the most important parts of the glaucoma evaluation because it identifies mechanisms. Without it, clinicians can miss narrow angles, chronic angle closure, pseudoexfoliation, pigment dispersion, angle recession, or other secondary causes that completely change the diagnosis and management plan. In other words, gonioscopy tells you what kind of glaucoma process you may be dealing with.2-4
The exam should assess angle width, visibility of angle structures, pigment, pseudoexfoliative material, peripheral anterior synechiae, and signs of prior trauma or secondary angle pathology. This step is not optional just because the OCT is available. A patient with suspicious RNFL thinning and an open angle does not follow the same path as a patient with chronic angle-closure features.
Short on time? Download the Glaucoma Evaluation and Management Flowchart!
Capture OCT images of the RNFL and macula
OCT has become indispensable in modern glaucoma workup because it provides objective, quantitative structural data. Peripapillary RNFL analysis remains a core tool, and macular ganglion cell analysis adds important value, particularly in early disease and cases with suspected central involvement. Large-evidence syntheses have shown strong diagnostic performance for average RNFL thickness and segmented macular parameters such as GCC and GCIPL.9,10
Still, OCT must be interpreted like a clinician, not a color-coded printout. The report should be reviewed for scan quality, segmentation error, and artifact before any diagnostic weight is placed on the results.
Myopia, media opacity, anomalous discs, and poor signal strength can all create misleading maps. The best OCT interpretation is topographic: does the thinning pattern make sense, and does it match the clinical disc exam and the visual field?9,10
A quick OCT review should include:
- Average RNFL thickness
- Sector and quadrant thinning
- Macular ganglion cell analysis
- Probability and deviation maps
- Inter-eye symmetry
- Signal strength and segmentation quality
Test visual fields
Visual field testing provides the functional half of the diagnosis. Standard automated perimetry, usually with a 24-2 strategy, is still central to glaucoma workup and follow-up. The goal is to determine whether suspected structural damage is producing repeatable glaucomatous functional loss in a pattern that makes anatomic sense.2,3
That said, not all visual field strategies capture the same disease equally well. A 24-2 can miss central macular damage because the central field is under-sampled. When OCT or symptoms suggest paracentral or central involvement, a 10-2 field may reveal meaningful functional loss that would otherwise be underestimated.11
When interpreting fields, always start with reliability. Then look for repeatability, topographic consistency, and structure-function agreement. One abnormal printout does not equal confirmed glaucoma, but a repeatable defect that matches disc and OCT changes is far more persuasive.
Perform additional testing (if needed)
Additional testing should be ordered with a purpose. It is most useful when the diagnosis is uncertain, progression risk needs refinement, or standard testing does not line up cleanly. Baseline disc photography can be extremely helpful for future comparison.
OCT angiography may add vascular information in selected patients, especially when progression or advanced disease is being evaluated. In atypical or equivocal cases, electrophysiologic testing such as visual evoked potential may provide supportive evidence of early optic nerve dysfunction.10,12
Useful adjuncts may include:
- Baseline optic nerve photography
- 10-2 visual fields
- OCT angiography
- Anterior segment imaging
- Electrophysiologic testing
- Neuro-ophthalmic referral when the pattern is atypical
The key is restraint. Additional testing should answer a specific clinical question. If it does not improve certainty or change management, it probably does not need to be ordered.
How to synthesize the data to make a diagnosis
After the workup is complete, the clinician’s task is to synthesize rather than simply count abnormal findings. A glaucoma suspect is typically a patient with one or more concerning features—such as elevated IOP, suspicious disc appearance, thin cornea, borderline OCT thinning, or equivocal field loss—but without enough reproducible evidence to confirm established glaucomatous optic neuropathy.
These are common patients in everyday practice, and they demand judgment more than speed.2,4 A glaucoma diagnosis becomes much more convincing when structure and function agree. Inferior rim thinning that matches superior field loss. Focal RNFL damage that aligns with a reproducible arcuate defect. Macular ganglion cell loss that explains a paracentral complaint.
That type of structure-function correlation is the real backbone of diagnosis. It also helps separate glaucoma from high-myopia change, anomalous discs, nonglaucomatous optic neuropathies, and artifact-driven OCT abnormalities.1,10,11
Initial management decisions
Once a full assessment has been completed, the next step is establishing the parameters you will utilize when moving forward with monitoring and management.
Determining target IOP
Once glaucoma or a high-risk suspect state is identified, the next major question is target IOP. Target IOP is not one universal number. It is a practical pressure range intended to reduce the risk of future progression in a particular patient.
The more advanced the damage, the lower that target generally needs to be. It should also be adjusted over time based on follow-up findings, age, vascular status, rate of progression, and the patient’s overall treatment burden.13
A practical way to think about target IOP is by disease severity:
- Mild disease: Modest reduction may be acceptable initially
- Moderate disease: Lower target usually needed
- Severe disease: More aggressive pressure lowering often required
The important point is that target IOP is dynamic. It should be revisited when fields, OCT, or disc findings suggest continued change.
Deciding between treatment vs. monitoring
Not every suspicious eye needs treatment on day 1. A low-risk suspect with borderline findings and no evidence of progression may be monitored with repeat testing and careful follow-up.
Conversely, a high-risk suspect, especially one with thin corneas, disc hemorrhage, strong family history, or convincing structural progression, may deserve a shorter follow-up interval or earlier intervention. Confirmed glaucoma with repeatable structural and functional loss usually warrants treatment rather than observation.3,4,6
This is where the entire workup earns its value. The more complete and reliable the baseline data, the easier it is to decide whether the patient is stable, converting, or already progressing.
First-line therapies
First-line therapy is usually aimed at lowering IOP, because it remains the only proven modifiable factor for slowing glaucoma progression. In many patients, this begins with topical medication, often a prostaglandin analog.
Selective laser trabeculoplasty is also an important first-line or adjunctive option in the right setting. The final choice should take into account angle anatomy, disease severity, adherence likelihood, ocular surface status, systemic contraindications, and patient preference.3,4,13
The goal of treatment is not simply to produce a better number at the next visit. It is to preserve visual function over the patient’s lifetime.
5 key takeaways
A glaucoma workup is most effective when it is done in a consistent sequence. The sequence should move from risk recognition to mechanism, then from structural evidence to functional confirmation.
- History and risk assessment shape pretest probability and help uncover secondary causes.
- IOP matters, but it never makes or excludes the diagnosis by itself.
- Pachymetry and gonioscopy add critical context that changes how the rest of the workup is interpreted.
- OCT and visual fields are strongest when they are read together, not separately.
- Treatment decisions become clearer when baseline data are complete and structure-function correlation is strong.1-4,9-11,13
Final thoughts
A glaucoma workup should feel organized, not improvised. The best evaluations do not rely on one “best” test. They combine history, pressure, corneal thickness, angle assessment, optic nerve evaluation, OCT, and perimetry into a logical sequence that improves diagnostic accuracy and makes management decisions more defensible.1-4
For optometrists, fellows, and residents, that structure is more than a good workflow. It is good patient care. When the process is consistent, clinicians are less likely to over-label suspicious patients, less likely to miss real disease, and better equipped to intervene before vision loss becomes irreversible.
