Visual Field Assessment

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The confrontation test is a quick screening test for gross visual field defects that can be done at the bedside. Spectacles should not be worn during the test as they may cause spurious visual field defects.

Technique

1. Seat yourself directly opposite to the patient, at one arm’s length away from each other. Test each eye separately. Ask the patient to cover the non-tested eye, while you cover the eye directly opposite to the patient’s non-tested eye. Therefore your uncovered eye is now directly facing the patient’s tested eye.
2. Ask the patient to focus on either your nose or your uncovered eye for the examination. Focusing on the uncovered eye is preferred to make the patient’s visual field match up with yours as much as possible. Make sure the patient remains focused on your nose or your uncovered eye during the examination.
3. Finger counting test: Hold both your arms out so that your hands are equidistant between you and the patient. Place each hand in 1 of the 4 visual field quadrants. Instruct the patient to count how many fingers you are holding up (do this 2 times for each quadrant). Then repeat this for the last 2 quadrants. This test only works if the patient retains good visual acuity.
4. Moving finger test: For each of the 4 visual field quadrants, start at the peripheral corner and progressively work your way towards the centre until the patient can see your moving finger.
5. Repeat the tests for the other eye, using your contralateral eye.

Clinical importance

The site of the lesion along the visual pathway determines the type of visual field defect seen. In general, because it measures only the outer edge of your visual field, the confrontation test is mainly useful in looking for large visual field defects, such as:

• Bitemporal hemianopia (suprasellar space-occupying lesions)
• Homonymous hemianopia (stroke, space-occupying lesions)
• Homonymous quadranopia (stroke, space-occupying lesions)

Inflammatory, toxic, hereditary and nutritional-deficiency related optic neuropathies tend to give central scotomas or centro-caecal scotomas, which are difficult to pick up on confrontation tests.

Glaucomatous optic neuropathies (glaucoma) commonly begin with nasal visual field defects, but are small and easily missed on confrontation tests.

Common mistakes in examinations

• Forgetting to test each eye separately.
• Forgetting to test the visual fields on the nasal side.
• Failure to notice a nasal visual field defect. It is important to remember that the nasal visual field goes up to 60°.