Visual field defects: How easily can they be fabricated using the automated perimeter?

Abstract

Visual field defects are often a sign of serious neurological disease, but can sometimes be of functional origin. This study examined the efficacy of automated perimetry at identifying simulated visual field defects. Volunteers attempted to fabricate four specific types of field defect, such as would normally be caused by serious neurological disease, on an automated perimeter with a threshold-related strategy. Twelve subjects were able to fabricate a variety of convincing and potentially serious visual field defects. Furthermore, using a more detailed threshold test, it was still possible to fabricate convincing field defects that were highly reproducible. Automated perimetry should not be relied upon to identify functional visual loss.

Key Words:

• Visual fields
• functional visual loss
• automated perimetry