False Positive Hemianopia

A 70-year-old woman was urgently referred for neuro-ophthalmic evaluation when a routine visual field test demonstrated a pattern of bilateral nasal hemianopia. Detailed inspection of the visual field study revealed the hemianopias to be artifactual for the following reasons: (1) it was performed with an excessive number of false positive responses; (2) the grey scale plot had white patches, consistent with abnormally high sensitivity; (3) the total deviation probability maps were normal, indicating that no tested points had poor scores. Confrontational visual field testing was normal in all zones for both eyes. Repeated visual field testing showed no evidence of a true hemianopia. Even automated visual fields with highly specific abnormalities can merely be testing artifact. Scrutinize all components of the report before determining the clinical implications.