OH

Optometry Hub

Clinical Guides

Perimetry Clinical Guide

Step-by-step protocol for visual field testing including test selection, technique, reliability, interpretation, and optometric management pathways.

Last updated: March 2026

Clinical Guide Overview

1. Clinical Importance

Perimetry quantifies differential light sensitivity across the visual field and is central to detecting functional loss from glaucoma, optic neuropathies, retinal disease, and intracranial pathology. The test creates a map of visual sensitivity that can be compared to age-matched norms, tracked over time, and correlated with structural findings such as optic nerve OCT.

Standard automated perimetry (SAP) is the clinical workhorse. Other modalities include kinetic perimetry (useful for peripheral field and low-vision patients), short wavelength automated perimetry (SWAP) for early glaucomatous change, and frequency doubling technology (FDT) for rapid screening. Reliable technique, consistent test parameters, and careful patient coaching are required for meaningful results.

Key Concepts

  • Threshold testing: Determines the dimmest stimulus the patient detects.
  • Global indices: Summarize field status (MD, PSD, VFI).
  • Pattern analysis: Distinguishes localized loss from diffuse depression.
  • Progression analysis: Event and trend analysis guide management changes.

A. Clinical Roles

Key Clinical Roles

  • Glaucoma detection and monitoring: Identifies early functional loss and progression trend.
  • Neuro-ophthalmic diagnosis: Localizes lesions along the visual pathway.
  • Retinal disease assessment: Detects scotomas from macular, vascular, or photoreceptor disease.
  • Medication toxicity surveillance: Detects early functional loss before structural change.
  • Medicolegal documentation: Supports fitness-to-drive and disability evaluations.

Glaucoma Care Impact

Perimetry is the primary functional metric used to stage glaucoma severity, assess progression, and determine when to escalate therapy or refer for surgical management. Serial fields are required to distinguish true progression from test variability.

Neuro Localization

Patterns that respect the vertical meridian (hemianopia, quadrantanopia) often indicate post-chiasmal disease and require urgent neuroimaging, while arcuate defects respecting the horizontal meridian suggest glaucomatous damage.

B. Indications

  • Glaucoma suspects or confirmed glaucoma (OHT, disc hemorrhage, RNFL thinning).
  • Optic nerve head changes (cupping, pallor, rim thinning, asymmetry).
  • Neuro symptoms (headache, field loss, diplopia, ptosis, afferent defect).
  • Retinal pathology (macular disease, vascular occlusion, pigmentary disorders).
  • Unexplained visual complaints (blur, night vision issues, glare, reading difficulty).
  • Medication monitoring (hydroxychloroquine, ethambutol, vigabatrin).
  • Post-treatment monitoring (post-laser, post-surgical, IOP management changes).
  • Occupational or driving assessments when required by local regulations.

2. Equipment and Tools

Core Equipment

  • Standard automated perimeter: Humphrey, Octopus, or equivalent SAP device.
  • Response button: Confirm comfortable grip and minimal movement.
  • Refractive correction: Trial lens set or built-in lens system.
  • Occluder: Patching of the non-tested eye without pressure.
  • Chin and forehead rest: Stable alignment and repeatable positioning.
  • Lens holder and trial lenses: Avoid rim artifact and lens decentration.

Optional or Specialized Tools

  • Kinetic perimetry: Goldmann or equivalent for peripheral field mapping.
  • FDT perimetry: Rapid screening and early glaucoma detection.
  • SWAP: Blue-on-yellow test for early glaucomatous damage.
  • Microperimetry: Central field mapping and macular function correlation.

Standard Parameters to Note

  • Stimulus size: Goldmann size III is standard for SAP.
  • Background luminance: Fixed by device; do not alter between visits.
  • Fixation target: Central dot or cross, consistent across visits.

3. Patient Preparation

Pre-Test Checklist

  • Confirm refractive correction: Use appropriate near correction for test distance.
  • Check pupil size: Small pupils can reduce sensitivity; note size in chart.
  • Review history: Medications, fatigue, headache, neurologic symptoms.
  • Ocular surface: Treat dry eye or tearing before test if needed.
  • Explain the test: Emphasize fixation, blinking, and honest responses.
  • Comfort and alignment: Adjust chin and forehead rest; check lens position.
  • Non-tested eye: Patch without pressure to avoid inducing ptosis.

4. Test Selection

Common Test Patterns

  • 24-2 or 30-2: Standard for glaucoma and neuro-ophthalmology.
  • 24-2C: Adds central points, better for early macular involvement.
  • 10-2: Central field for macular disease or advanced glaucoma.
  • 60-4 or 120: Peripheral mapping in neuro or retinal disease.
  • Esterman binocular: Functional fields for driving and disability.

Testing Strategies

  • Threshold strategies: SITA Standard, SITA Fast, or equivalent.
  • Full threshold: Longer, higher precision for complex cases or research.
  • Screening: Faster but less sensitive to subtle defects.

Program Selection Tips

  • Glaucoma suspects: 24-2 or 24-2C with a threshold strategy.
  • Macular disease: 10-2 or microperimetry when available.
  • Neuro field loss: 30-2 or 60-4 for vertical meridian defects.
  • Advanced glaucoma: 10-2 for central islands and functional vision.

5. Step-by-Step Technique

Step 1: Position and Align

  1. Seat patient comfortably with chin and forehead stabilized.
  2. Occlude the non-tested eye without pressure (avoid induced ptosis).
  3. Align pupil to the perimeter marker; center the corneal reflex.
  4. Insert trial lens with correct vertex distance to reduce rim artifact.
  5. Check eyelids and brow position; tape lids if needed for ptosis.

Step 2: Patient Instructions

  1. Explain that small lights will appear in peripheral vision.
  2. Fixate on the central target throughout the test.
  3. Press the button only when a light is seen, even if unsure.
  4. Blink normally to avoid dryness; pause if the eye waters.
  5. Reassure that missing some lights is expected and normal.

Step 3: Start the Test

  1. Select test pattern and strategy based on indication.
  2. Confirm correct eye, refraction, and patient data in the system.
  3. Begin testing and verify fixation monitoring is active.
  4. Use gaze tracking or blind-spot checks to verify fixation.

Step 4: Monitor and Coach

  1. Watch fixation losses, false positives, and gaze tracking.
  2. Encourage steady fixation and calm responses.
  3. Pause for a brief break if fatigue or tearing appears.
  4. Stop and restart if patient becomes confused or loses fixation repeatedly.

Step 5: End and Review

  1. Repeat for the fellow eye after a short rest.
  2. Check reliability indices, test duration, and gaze tracking plots.
  3. Review printouts for artifacts (lid, lens rim, fatigue).
  4. Compare with previous fields and structural findings.

6. Reliability & Quality Control

Reliability Indices

  • Fixation losses: Target less than 20 percent; interpret with gaze tracking.
  • False positives: Target less than 15 percent; high values suggest trigger-happy response.
  • False negatives: Target less than 20 percent; high values suggest fatigue or inattention.
  • Test duration: Long tests reduce reliability; consider faster strategies.
  • Learning effect: First fields show variability; repeat to confirm defects.

Common Artifacts

  • Lid or brow artifact: Superior depression, improves with lid taping.
  • Trial lens rim artifact: Peripheral ring scotoma from lens decentration.
  • Dry eye or tearing: Generalized depression or scattered defects.
  • Poor fixation: Inconsistent defects not respecting anatomic patterns.

7. Interpretation

Core Outputs to Review

  • Gray scale: Quick visualization of sensitivity loss (not diagnostic alone).
  • Total deviation: Raw sensitivity compared to age-matched norms.
  • Pattern deviation: Removes generalized depression and highlights localized loss.
  • Global indices: MD, PSD, and VFI for overall status.
  • Glaucoma hemifield test: Compares superior and inferior field symmetry.
  • Progression analysis: Event and trend analysis when available.

Interpretation Workflow

  1. Confirm reliability indices and look for artifacts.
  2. Assess generalized depression (media opacity, small pupil, fatigue).
  3. Evaluate localized defects on pattern deviation.
  4. Check whether defects respect horizontal or vertical meridian.
  5. Correlate with optic nerve, OCT, and clinical findings.
  6. Compare with prior fields for progression (event and trend).

Staging Guidance

  • Early disease: Localized defects, mild MD reduction.
  • Moderate disease: Defects approaching fixation or multiple clusters.
  • Advanced disease: Central islands or severe MD loss.

Use a consistent staging system (for example, Hodapp-Parrish-Anderson) to guide monitoring intervals and escalation decisions.

8. Common Visual Field Defects

  • Paracentral scotoma: Early glaucoma, macular disease, or optic neuritis.
  • Nasal step: Glaucomatous defect respecting horizontal meridian.
  • Arcuate scotoma: Classic glaucomatous RNFL pattern.
  • Altitudinal defect: Ischemic optic neuropathy or retinal vascular occlusion.
  • Central scotoma: Optic neuritis, toxic neuropathy, macular pathology.
  • Bitemporal hemianopia: Chiasmal lesion (pituitary tumor).
  • Homonymous hemianopia: Post-chiasmal lesion (stroke, tumor).
  • Quadrantanopia: Temporal or parietal lobe lesions.

9. Special Populations

  • Children: Use shorter strategies or kinetic perimetry; extra coaching.
  • Elderly patients: Expect slower responses and fatigue; allow breaks.
  • Low vision: Larger stimulus size or kinetic testing for peripheral fields.
  • Cognitive impairment: Simplify instructions; consider screening only.
  • High myopia: Increased false positives; consider test repeat and structural correlation.
  • Ptosis or dermatochalasis: Tape lids to avoid superior artifact.

10. Treatment Protocols for Optometry Practice

Glaucoma Management

  • Baseline: Two to three reliable fields in the first year to establish variability.
  • Monitoring cadence: Early disease every 6 to 12 months; moderate every 4 to 6 months; advanced every 3 to 4 months, adjusted by risk.
  • Progression analysis: Use event and trend analysis where available.
  • Structure-function correlation: Compare with OCT RNFL and GCC.
  • Escalation: Consider additional therapy or referral if confirmed progression.

Neuro-Ophthalmic Defects

  • Urgent referral: New hemianopia, bitemporal defects, or sudden field loss.
  • Neuroimaging: MRI preferred when available; CT when urgent or MRI unavailable.
  • Red flags: Field loss with headache, neurologic symptoms, or optic disc edema.
  • Follow-up: Repeat fields after treatment or surgery to confirm recovery.

Retinal Disease and Toxicity Monitoring

  • Macular disease: Use 10-2 or microperimetry when available.
  • Vascular occlusions: Document scotomas and monitor for changes.
  • Hydroxychloroquine: Baseline test within first year, then annual screening after 5 years (earlier if high risk). Use 10-2, or 24-2/30-2 in Asian patients.
  • Ethambutol or vigabatrin: Baseline and periodic monitoring with SAP and color vision.

Referral Thresholds (Global Guidance)

  • Emergency: Acute field loss, new hemianopia, papilledema, or neurologic signs.
  • Urgent: Progressive glaucomatous loss despite therapy or rapid MD decline.
  • Routine: Stable defects needing specialist confirmation or co-management.

11. Clinical Pearls & Best Practices

Pearl 1: Reliability First

Never interpret a field without acceptable reliability indices. Repeat tests when fixation losses or false positives are high. A reliable normal field is more valuable than an unreliable abnormal one.

Pearl 2: Expect Learning Effects

The first test often appears worse due to unfamiliarity. Repeat to confirm defects before changing treatment, especially in low-risk patients.

Pearl 3: Correlate Structure and Function

Visual field defects should align with optic nerve or OCT findings. Discordant results require repeat testing or alternate diagnoses.

Pearl 4: Use 10-2 for Central Loss

Central glaucomatous defects or macular pathology are better assessed with 10-2 or 24-2C programs.

Pearl 5: Be Consistent

Use the same perimeter, strategy, and test pattern for serial monitoring. Switching methods reduces comparability and can mask progression.

Pearl 6: Fatigue Mimics Disease

Fatigue can cause diffuse depression or false defects. Offer breaks and keep testing sessions short to improve reliability, especially in older patients.

Pearl 7: Avoid Lens Rim Artifacts

Ensure proper trial lens centration and vertex distance. A rim artifact can mimic arcuate defects or peripheral loss. Adjust lens position and repeat if suspected.

Pearl 8: Manage Lids and Brow

Dermatochalasis or ptosis can cause superior depression. Tape lids when needed and document the adjustment to aid interpretation and repeatability.

Golden Rule of Perimetry

"Reliable fields drive safe decisions." Perimetry informs diagnosis, treatment, and referral. Prioritize quality, repeat when in doubt, and always interpret fields alongside optic nerve findings and patient symptoms.

Quick Reference Protocol

  1. Confirm indication, select appropriate pattern (24-2/24-2C/10-2/30-2), and apply correct refractive correction.
  2. Position and align patient carefully; patch fellow eye without pressure; manage lids if ptosis/dermatochalasis is present.
  3. Provide clear instructions on fixation, blinking, and button response before starting.
  4. Monitor reliability during testing (fixation losses, false positives/negatives, gaze tracking) and pause if fatigue or tearing occurs.
  5. Interpret only reliable fields, correlate with optic nerve/OCT and symptoms, and repeat testing if findings are inconsistent.
  6. Document defect pattern, severity, progression status, and management plan including follow-up interval or referral urgency.

Documentation and Communication

  • Record test setup: eye tested, program/strategy, correction used, pupil status, and any lid taping or test interruptions.
  • Record reliability: fixation losses, false positives/negatives, gaze tracking quality, and whether the test is clinically interpretable.
  • Describe findings: defect pattern, meridian behavior, global indices (MD/PSD/VFI), and progression status compared with prior tests.
  • Correlate clinically: note agreement or discordance with optic disc/OCT findings and symptoms.
  • Document action: monitoring interval, treatment escalation, repeat test timing, and urgency/type of referral when indicated.

Communicate results to patients in plain language, including what was found, why follow-up timing matters, and the warning symptoms that require urgent reassessment.

References

  1. Anderson DR, Patella VM. Automated Static Perimetry. 2nd ed. St. Louis: Mosby; 1999.
  2. Hodapp E, Parrish RK II, Anderson DR. Clinical Decisions in Glaucoma. St. Louis: Mosby; 1993.
  3. Heijl A, Lindgren G, Olsson J. Normal variability of static perimetric threshold values. Acta Ophthalmol. 1987;65(4):475-478.
  4. Heijl A, Bengtsson B, Chauhan BC, et al. A practical guide to visual field interpretation. Ophthalmology. 2012;119(2):478-485.
  5. Katz J, Sommer A, Gaasterland DE, Anderson DR. Reliability indices in automated perimetry. Ophthalmology. 1993;100(6):1010-1016.
  6. Bengtsson B, Heijl A. False-negative responses in computerized perimetry. Ophthalmology. 2000;107(5):863-867.
  7. Artes PH, O'Leary N, et al. Frequency of testing required to detect glaucoma progression. Ophthalmology. 2014;121(4):821-826.
  8. Vesti E, Johnson CA, Chauhan BC. The effect of learning on automated perimetry. Arch Ophthalmol. 2003;121(9):1349-1354.
  9. Varma R, et al. Visual field defects in glaucoma and their associations. Ophthalmology. 2005;112(4):540-548.
  10. Musch DC, Lichter PR, Guire KE, Standardi CL. The Collaborative Initial Glaucoma Treatment Study: visual field progression. Ophthalmology. 2009;116(2):200-209.
  11. American Academy of Ophthalmology. Preferred Practice Pattern: Primary Open-Angle Glaucoma. San Francisco: AAO; 2023.
  12. European Glaucoma Society. Terminology and Guidelines for Glaucoma. 6th ed. Savona: EGS; 2020.
  13. World Health Organization. ICD-11: Vision impairment and blindness classification. Geneva: WHO; 2018.
  14. Johnson CA, Samuels SJ. Screening for visual field defects: FDT and SAP. Ophthalmology. 1997;104(12):2120-2126.
  15. Wall M, Johnson CA, Cello KE. Frequency-doubling perimetry. Surv Ophthalmol. 1997;41(5):311-322.
  16. Rabinowitz MP, et al. 10-2 perimetry in macular disease. Retina. 2014;34(4):704-712.
  17. Kass MA, et al. The Ocular Hypertension Treatment Study: visual field outcomes. Arch Ophthalmol. 2010;128(3):276-287.
  18. Hood DC, et al. Structure function relationships in glaucoma. Invest Ophthalmol Vis Sci. 2007;48(7):3001-3007.
  19. Hood DC, Raza AS. On improving the use of OCT and visual fields. Ophthalmology. 2014;121(6):1307-1312.
  20. Keltner JL, et al. Visual field defects in neuro-ophthalmology. J Neuroophthalmol. 2001;21(1):18-24.
  21. Rowe FJ, et al. Visual field defects after stroke and rehabilitation outcomes. Clin Rehabil. 2013;27(5):431-444.
  22. Marmor MF, Kellner U, Lai TY, Melles RB, Mieler WF. Recommendations on screening for chloroquine and hydroxychloroquine retinopathy. Ophthalmology. 2016;123(6):1386-1394.