Visual Field Reference Card: Reliability, Glaucoma Criteria and Staging
Last updated: October 2026
A checklist for Humphrey-type automated perimetry printouts: reliability, is it glaucoma, how severe, and does the pattern point elsewhere?
Step 1: identify the test and the patient
- Name, age, the eye tested, pupil size, refraction used and visual acuity. A small pupil or the wrong near add depresses the whole field.
- Test pattern: 24-2 for glaucoma screening and follow-up; 10-2 for advanced glaucoma, central defects and hydroxychloroquine screening; 30-2 for neurological work-ups. The algorithm (SITA Standard, Fast or Faster) affects test time and variability.
- Is this the patient's first or second field? The first field often shows a learning effect, so confirm any defect on a repeat test.
Step 2: reliability indices
| Index | Commonly accepted limit | Comment |
|---|---|---|
| Fixation losses | 20% or less | Often over-flagged (blind-spot mapping error). Check the gaze tracker trace. |
| False positives | 15% or less (some use 10%) | The most important index. A "trigger-happy" patient produces an impossibly good field with white patches on the greyscale. |
| False negatives | 33% or less | Fatigue or inattention, but high false negatives are expected in advanced glaucoma |
Step 3: is it glaucomatous? (Anderson-Patella minimum criteria)
Any one of the following, confirmed on two consecutive reliable fields:
- Glaucoma Hemifield Test "outside normal limits".
- A cluster of 3 or more contiguous non-edge points on the pattern deviation plot depressed at p < 5%, with at least one at p < 1%.
- Pattern standard deviation (PSD) significant at p < 5%.
The defect should respect the horizontal meridian, match the disc and OCT findings, and follow the nerve fibre pattern (nasal step, arcuate, paracentral).
Step 4: how severe? (Hodapp-Parrish-Anderson staging, 24-2 or 30-2)
| Stage | Mean deviation | Pattern deviation points | Central 5° |
|---|---|---|---|
| Early | Better than −6 dB | Fewer than 18 points at p < 5% and fewer than 10 at p < 1% | No point under 15 dB |
| Moderate | −6 to −12 dB | Fewer than 37 points at p < 5% and fewer than 20 at p < 1% | No absolute (0 dB) point; under 15 dB in only one hemifield |
| Severe | Worse than −12 dB | 37 or more points at p < 5%, or 20 or more at p < 1% | Any 0 dB point, or points under 15 dB in both hemifields |
A field is staged by the worst criterion met. VFI (visual field index) expresses remaining function as a percentage and is useful for plotting rate of progression.
Step 5: progression
- Guided Progression Analysis (GPA) needs two baselines plus follow-up tests. "Possible progression" means 3 or more points worse than baseline (p < 5%) on two consecutive tests; "likely progression" means the same on three consecutive tests.
- Look at the VFI or MD slope: a loss of about 1 dB a year or more is fast for most patients.
- Six fields in the first two years is the ideal to estimate the rate reliably in newly diagnosed glaucoma.
Step 6: patterns that are not glaucoma
| Pattern | Think of |
|---|---|
| Respects the vertical meridian (hemianopia, quadrantanopia) | Chiasmal or retrochiasmal lesion: image the brain. Bitemporal: chiasm; homonymous: optic tract to occipital cortex. |
| Central or centrocaecal scotoma | Optic neuritis, toxic or nutritional neuropathy, LHON, macular disease |
| Altitudinal defect | NAION, branch retinal artery occlusion, advanced glaucoma |
| Enlarged blind spot | Papilloedema, disc drusen, MEWDS, peripapillary atrophy |
| Generalised depression (total deviation low, pattern deviation normal) | Cataract or media opacity, small pupil, wrong refraction |
| "Cloverleaf" or progressively constricting field | Fatigue or non-organic loss |
| Ring scotoma | Retinitis pigmentosa, high plus lens (aphakic correction) artefact |
Before you act: rule out a lens rim artefact (edge points depressed), a ptotic lid (superior defect that lifts with taping), and a learning effect. Repeat any new defect before changing treatment.
Related: how to read a visual field (detailed tips), visual field defect localisation, perimetry algorithms and the OCT disc card.
Key sources
- Anderson DR, Patella VM. Automated Static Perimetry. 2nd ed. Mosby; 1999
- Hodapp E, Parrish RK II, Anderson DR. Clinical Decisions in Glaucoma. Mosby; 1993
- Chauhan BC et al. Practical recommendations for measuring rates of visual field change in glaucoma. Br J Ophthalmol 2008;92:569–73
- Reliability index limits (Eyes On Eyecare)
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Looking for an eye specialist in Ahmedabad? Read about visual field testing at Sadbhaav or book a consultation with Dr. Dhaval Patel.
