Artifacts and Nonglaucomatous Abnormalities in Visual Fields

Dr. Anna Singh reviews the artifacts and pitfalls in the interpretation of visual fields. Visual field testing is critical for assessment and to document progression of glaucoma, but is inherently prone to errors and artifacts. Common causes for artifacts include patient-related factors; eye-related factors; central nervous system defects; and optic disc, optic nerve, and chorioretinal disorders. To avoid common pitfalls, she recommends using this practical checklist:

• Fixation loss less than 33%
• False-positive errors less than 33%; false-negative errors less than 33%
• Appropriate scan: SITA Fast for screening, SITA standard for monitoring
• Appropriate age correction (for comparison with normative database)
• First field test considered a learning test
• Confirm visual field abnormality in 3 consecutive abnormal and reliable visual field tests with the defect in the same location.
• Careful assessment of structure-function correlation (disc photos, OCT, retinal nerve fiber layer)