How do I examine a patient's binocular visual fields to ensure at least 120° continuous horizontal field and at least 15° continuous field above and below fixation?

Binocular Visual Field Examination Technique for 120° Horizontal and 15° Vertical Fields

To examine binocular visual fields for 120° continuous horizontal and 15° continuous vertical extent, position yourself at arm's length from the patient, have them fixate on your nose with both eyes open, and systematically bring a red target from the periphery inward along the horizontal meridian (60° temporally on each side) and vertical meridian (15° above and below fixation), asking the patient to report when they first see the target.

Patient Positioning and Setup

• Position the patient seated comfortably at approximately 30-100 cm from you, with both of you at eye level 1
• Ensure the patient maintains fixation on your nose or a central fixation point throughout the examination 2, 1
• Keep both of the patient's eyes open simultaneously for binocular field assessment 2
• Use adequate room lighting to allow visualization of the red target 3, 1

Target Selection and Rationale

• Use a red target (such as a red pin, red square card, or red-topped pin) rather than finger wiggling, as red color desaturation testing is significantly more sensitive for detecting visual field defects 3, 1
• A red square test card or red pin at 30 cm distance provides high sensitivity for detecting even minor field defects 3
• The red target should be approximately 5-10 mm in diameter for optimal detection 1

Systematic Examination Technique

Horizontal Meridian Assessment (120° Total)

• Start with the target positioned 60° temporally in the right visual field (patient's right side) 1
• Slowly bring the red target along the horizontal meridian toward central fixation 1
• Ask the patient: "Tell me when you first see the red target" 3, 1
• Mark the point where the patient reports seeing the target
• Repeat from 60° temporally on the left side 1
• The patient should detect the target continuously along the entire 120° horizontal extent (60° temporal on each side) 2

Vertical Meridian Assessment (30° Total)

• Position the red target 15° above fixation in the superior field 1
• Bring the target downward along the vertical meridian through fixation 1
• Continue to 15° below fixation in the inferior field 1
• Ask the patient to report continuous visualization of the red target throughout this 30° vertical range 3, 1
• The patient should maintain detection throughout the entire 15° above and 15° below fixation 2

Alternative Technique: Red Desaturation Comparison

• Present the red target simultaneously in different quadrants or along meridians 3
• Ask the patient to compare the intensity or saturation of the red color at different locations 3
• Any area where the red appears "washed out" or less saturated indicates a relative field defect 3
• This comparative method is particularly sensitive for detecting subtle defects 3

Interpretation and Documentation

• Normal binocular fields should show continuous detection along the entire 120° horizontal meridian and 15° above and below fixation 2
• Any area where the patient fails to detect the red target or reports decreased color saturation represents a field defect 3, 1
• Document the extent of any defects in degrees from fixation 2, 1
• Note whether defects respect the vertical midline (suggesting neurological pathology) or cross it (suggesting glaucomatous or other ocular pathology) 4, 5

Common Pitfalls to Avoid

• Do not use finger wiggling or hand movement alone—this technique lacks sensitivity for detecting subtle but clinically significant defects 3, 1
• Ensure the patient maintains steady central fixation throughout; fixation breaks invalidate the examination 2
• Test both eyes together for binocular assessment, not monocularly 2
• Do not rush the examination—bring targets slowly enough for the patient to reliably detect them 1
• Verify that any detected defect is reproducible by retesting that area 1

When to Proceed to Formal Perimetry

• If bedside confrontation testing reveals any abnormality, confirm with automated static perimetry (Humphrey or Goldmann visual fields) 2
• Bedside testing is a screening tool; formal perimetry provides quantitative documentation necessary for diagnosis and monitoring 2
• Any defect detected on confrontation testing warrants formal perimetric confirmation before making treatment decisions 2