Objective Around 30 % of patients with acquired brain injury suffer from cerebral visual deficits. Visual field deficits can affect performance on neuropsychological tests that are presented visually. Thus, assessment of anopia is important when conducting neuropsychological assessments. The gold standard is to use automated perimetries such as Humphreys 750i. However, many neurological patients are not offered an auto-perimetry. We have therefore designed a user-friendly, computerized visual field screening test (c-VFT) that can complement neuropsychological assessments.
Participants and methods The c-VFT is a computer program written in open source Python using Psychopy and can be installed without a license. The program tests 48 points in the visual field, covering the visual field from 1 degree to 10 degrees in each hemifield. A colour change detection task controls fixation. Several parameters like the number of stimulus repetitions, the colour of stimuli and background, and the orientation of the layout can be individually set. The c-VFT probes all four quadrants and probes along the horizontal midline, making it particularly sensitive for visual field deficits that affect reading.
Results We will present the test itself, along with data from six patients with newly acquired visual field defects resulting from post-chiasmatic injury and no history of visual neglect. Patients’ results from the c-VFT will be compared with results from a standard Humphreys 750i perimetry.
Conclusion Preliminary analyses indicate that the c-VFT is a sensitive screening tool for visual field defects (anopias) that can be used in neuropsychological practice when other measures of visual field defects are lacking. It should, however, not be considered a diagnostic tool. Assessment can be performed quickly with minimal strain of patients’ cognitive resources, and test results are readily available to guide selection and interpretation of neuropsychological tests.