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Visual fields: confrontation, Amsler grid and perimetry

  • Examination

Confrontation finds large field defects at the bedside, the Amsler grid finds central distortion, and automated perimetry measures and follows the field.

Updated

See it in 3D: Retina · Optic nerve · Optic chiasm · Visual cortex

What it is

The visual field is all that each eye sees while looking straight ahead. Testing it localises lesions along the visual pathway and follows diseases such as glaucoma. Confrontation at the bedside detects large defects only. The Amsler grid tests the central field for distortion and missing patches. Automated static perimetry measures sensitivity point by point and is the standard for diagnosis and follow-up.

Normal values and scales

  • The normal monocular field reaches about 90 to 100 degrees temporally, 60 nasally, 60 above and 70 below.
  • The physiological blind spot (the optic disc) lies about 15 degrees temporal to fixation.
  • The Amsler grid covers the central 10 degrees around fixation.
  • Common perimetry programmes test the central 24 or 30 degrees; the central 10 degrees programme is used for advanced glaucoma and macular toxicity.
  • Reliability indices: fixation losses, false positives and false negatives.

How it is done

  1. Confrontation: sit about one metre in front of the patient, at eye level; the patient covers one eye and looks at the examiner's opposite eye.
  2. Present fingers in each of the four quadrants of that eye, halfway between centre and periphery, and ask how many are shown.
  3. Bring a target in from the periphery along each quadrant and compare with the examiner's own field.
  4. Compare the brightness of a red target on each side of the vertical midline: desaturation on one side suggests a hemianopic or chiasmal defect.
  5. Amsler grid: at reading distance, with reading glasses, one eye covered, the patient looks at the central dot and reports wavy lines or missing areas.
  6. Automated perimetry: each eye is tested in a bowl while the patient presses a button on seeing lights; the report gives the defects and reliability indices.

How to interpret it

  • A defect that respects the vertical midline comes from the chiasm or behind it; one that respects the horizontal midline comes from the optic nerve head or retina (glaucoma, ischaemic optic neuropathy, branch occlusions).
  • Glaucoma typically starts with arcuate or nasal step defects, sparing central vision until late.
  • New distortion on the Amsler grid in an older adult suggests neovascular macular degeneration.

Next step / Initial management

  • Defect on confrontation: formal automated perimetry and localisation of the lesion.
  • Bitemporal or homonymous defect: brain imaging (see the field localisation page).
  • New distortion on the Amsler grid: urgent ophthalmology (within days).
  • Glaucoma or drug toxicity follow-up: perimetry at intervals set by ophthalmology.

Test yourself

Think of the answer, then tap the question to see it.

Which field defect does a horizontal midline boundary suggest?

A lesion of the optic nerve head or retina, such as glaucoma, ischaemic optic neuropathy or a branch vessel occlusion.

What does the Amsler grid test?

The central 10 degrees of the field, for distortion or missing areas from macular disease.

Why is confrontation not enough to follow glaucoma?

It only detects large defects; glaucoma needs automated perimetry to measure and follow small changes.

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See it in 3D4

The structures of Durgical's 3D anatomy where it is found.

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Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.

Sources: Humphrey Visual Field (StatPearls Publishing (NCBI Bookshelf), 2025); Amsler Grid (StatPearls Publishing (NCBI Bookshelf), 2023); Neuroanatomy, Visual Pathway (StatPearls Publishing (NCBI Bookshelf), 2026).

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Representative model, for educational purposes only.