title: Collision avoidance in persons with homonymous visual field defects under virtual reality conditions.
abstract: The aim of the present study was to examine the effect of homonymous visual field defects (HVFDs) on collision avoidance of dynamic obstacles at an intersection under virtual reality (VR) conditions. Overall performance was quantitatively assessed as the number of collisions at a virtual intersection at two difficulty levels. HVFDs were assessed by binocular semi-automated kinetic perimetry within the 90° visual field, stimulus III4e and the area of sparing within the affected hemifield (A-SPAR in deg(2)) was calculated. The effect of A-SPAR, age, gender, side of brain lesion, time since brain lesion and presence of macular sparing on the number of collisions, as well as performance over time were investigated. Thirty patients (10 female, 20 male, age range: 19-71 years) with HVFDs due to unilateral vascular brain lesions and 30 group-age-matched subjects with normal visual fields were examined. The mean number of collisions was higher for patients and in the more difficult level they experienced more collisions with vehicles approaching from the blind side than the seeing side. Lower A-SPAR and increasing age were associated with decreasing performance. However, in agreement with previous studies, wide variability in performance among patients with identical visual field defects was observed and performance of some patients was similar to that of normal subjects. Both patients and healthy subjects displayed equal improvement of performance over time in the more difficult level. In conclusion, our results suggest that visual-field related parameters per se are inadequate in predicting successful collision avoidance. Individualized approaches which also consider compensatory strategies by means of eye and head movements should be introduced.
authors.affiliation: Center for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Germany. Eleni.Papageorgiou@med.uni-tuebingen.de
authors.forename: Eleni
authors.initials: E
authors.lastname: Papageorgiou
authors.forename: Gregor
authors.initials: G
authors.lastname: Hardiess
authors.forename: Hermann
authors.initials: H
authors.lastname: Ackermann
authors.forename: Horst
authors.initials: H
authors.lastname: Wiethoelter
authors.forename: Klaus
authors.initials: K
authors.lastname: Dietz
authors.forename: Hanspeter A
authors.initials: HA
authors.lastname: Mallot
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schiefer
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001334:Automobile Driving; D001362:Avoidance Learning / Q000502:physiology; D001927:Brain Diseases / Q000503:physiopathology; D016022:Case-Control Studies; D003198:Computer Simulation; D004215:Distance Perception / Q000502:physiology; D005260:Female; D006423:Hemianopsia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D009949:Orientation / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D013028:Space Perception / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult