VISUAL-FIELD DEFECTS - HOW EASILY CAN THEY BE FABRICATED USING THE AUTOMATED PERIMETER

Visual field defects are often a sign of serious neurological disease but can sometimes be of functional origin. This study examined the eff icacy of automated perimetry at identifying simulated visual field def ects. Volunteers attempted to fabricate four specific types of field d efect, such as would normally be caused by serious neurological diseas e, on an automated perimeter with a threshold-related strategy. Twelve subjects were able to fabricate a variety of convincing and potential ly serious visual field defects. Furthermore, using a more detailed th reshold test, it was still possible to fabricate convincing field defe cts that were highly reproducible. Automated perimetry should not be r elied upon to identify functional visual loss.