Saccade testing to distinguish between nonorganic and organic visual field restriction
- Martin S Zinkernagel (m.zinkernagel{at}gmail.com),
- Niccolo Pellanda (niccolo.pellanda{at}kssg.ch),
- Andrea Kunz (andrea.kunz{at}kssg.ch),
- Daniel S Mojon (daniel.mojon{at}kssg.ch)
- Lions eye institute, Perth, Australia
- Kantonsspital, Switzerland
- Kantonsspital, Switzerland
- Kantonsspital, Switzerland
- Published Online First 2 June 2009
Abstract
Aim: The authors described and tested a simple new bedside procedure to detect nonorganic visual field loss.
Methods: Prospective comparative observational case series of 16 patients with nonorganic visual field loss and 15 patients with organic visual field loss were examined. Saccade patterns provoked by a stimulus outside the claimed visual field were assessed by a masked observer.
Results: Whereas in organic visual field defects eye movements as noted by the observer were in small and erratic searching patterns towards the visual field defect in all patients (15/15), most (14/16) patients with nonorganic visual field loss were able to jump directly to the presented finger in one directional large saccade, although the stimulus was outside their stated visual field. The sensitivity of the saccade test in detection of nonorganic visual field loss by a masked observer was 87% (95% CI, 60%-97%) and the specificity was 100% (95% CI, 75%-100%). The positive predictive value for nonorganic visual field loss of the saccade test was 100% and the negative predictive value was 90%.
Conclusions: The saccade test is a quick and reproducible examination to use and is largely independent of the patient’s willingness for cooperation. The authors believe that the test will be of value to clinicians on bedside evaluation when nonorganic visual field loss is suspected.
