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Clinical Trial
. 2014 Aug 27;9(8):e106089.
doi: 10.1371/journal.pone.0106089. eCollection 2014.

Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study

Affiliations
Clinical Trial

Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study

Katrin Sippel et al. PLoS One. .

Abstract

Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001). Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD) area than patients who failed (t-test, p < 0.05). According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

Trial registration: ClinicalTrials.gov NCT01372319 NCT01372332.

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Conflict of interest statement

Competing Interests: The authors have the following interests. PFIZER Pharma GmbH, Berlin, Germany, and MSD, SHARP & DOHME GmbH, Haar, Germany provided financial support to this study. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Figures

Figure 1
Figure 1. The drug store corridor with all marked special-offer products (orange signs) on two racks (each containing six shelves).
Two cameras (marked by blue circles) at the beginning and the end of the corridor were used to record navigation of the subjects during the task.
Figure 2
Figure 2. Value range for (a) the average number of correctly collected items over all runs, (b) the average time needed to complete the supermarket search task over all runs, and (c) the average time (over all runs) per correctly collected item.
The participant subgroups are marked by GCp/GPp (glaucoma controls/patients who passed), GPf (glaucoma patients who failed).

References

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