Homonymous Visual Field Loss and Its Impact on Visual Exploration: A Supermarket Study.
OBJECTIVE
Homonymous visual field defects (HVFDs) may critically interfere with quality of life. The aim of this study was to assess the impact of HVFDs on a supermarket search task and to investigate the influence of visual search on task performance.


METHODS
Ten patients with HVFDs (four with a right-sided [HR] and six with a left-sided defect [HL]), and 10 healthy-sighted, sex-, and age-matched control subjects were asked to collect 20 products placed on two supermarket shelves as quickly as possible. Task performance was rated as "passed" or "failed" with regard to the time per correctly collected item (TC-failed = 4.84 seconds based on the performance of healthy subjects). Eye movements were analyzed regarding the horizontal gaze activity, glance frequency, and glance proportion for different VF areas.


RESULTS
Seven of 10 HVFD patients (three HR, four HL) passed the supermarket search task. Patients who passed needed significantly less time per correctly collected item and looked more frequently toward the VFD area than patients who failed. HL patients who passed the test showed a higher percentage of glances beyond the 60° VF (P< 0.05).


CONCLUSIONS
A considerable number of HVFD patients performed successfully and could compensate for the HVFD by shifting the gaze toward the peripheral VF and the VFD area.


CONCLUSIONS
These findings provide new insights on gaze adaptations in patients with HVFDs during activities of daily living and will enhance the design and development of realistic examination tools for use in the clinical setting to improve daily functioning. (http://www.clinicaltrials.gov, NCT01372319, NCT01372332).
Computer Engineering Department, University of Tübingen, Tübingen, Germany.
Enkelejda
E
Kasneci
Computer Engineering Department, University of Tübingen, Tübingen, Germany.
Katrin
K
Sippel
Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
Martin
M
Heister
Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
Katrin
K
Aehling
Computer Engineering Department, University of Tübingen, Tübingen, Germany.
Wolfgang
W
Rosenstiel
Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany ; Hochschule Aalen, Kompetenzzentrum Vision Research, Aalen, Germany.
Ulrich
U
Schiefer
Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany ; University of Leicester, Department of Ophthalmology, Leicester Royal Infirmary, United Kingdom.
Elena
E
Papageorgiou
Homonymous visual field defects; compensation; eye movements; supermarket search task; visual search