Thesis defense Karlijn Wouters (Donders series 422)
15 January 2020
Promotors: prof. dr. A. van Opstal, prof. dr. A. van den Berg (Universiteit Utrecht), co-promotors: dr. H. Goossens, dr. T. Theelen
Speed of vision in healthy aging and hemianopia
Modern daily life relies strongly on effective handling of visual
information. People who need more time to process such information can
experience problems driving, handling computers, and performing various
other common tasks. They may seek help from an ophthalmologist, but are
only eligible for visual rehabilitation programs if their visual acuity
and visual field are also affected or if they suffer from cerebral
visual impairment, eye defects or clear retinal pathology. Whether their
vision is too slow to adequately perform daily activities is generally
not taken into account, as speed is hardly incorporated in clinical
assessments of visual functioning. Aware of this issue, we have
investigated the additional value of temporal measures in the assessment
of visual functioning. We showed that both a psychophysical task called
the Useful Field of View task and electrophysiological measures are
sensitive to small age-related changes that may be missed by traditional
ophthalmological measures such as visual acuity and contrast
sensitivity. In addition, we demonstrated that the UFOV detects
disturbed visual functioning in the ipsilesional ‘intact’ hemifield of
patients with post-chiasmatic brain damage. To increase their
sensitivity to small deviations from normal functioning, both techniques
would benefit from further development of the paradigms or analysis
methods. Even so, in their present form they are already clinically
applicable and provide an opportunity to quantify visual speed.
Electrophysiology can provide more information about which part of the
visual system is affected than the UFOV task. However, due to the time
it takes to perform such measurements, the UFOV task may be more
suitable in a general ocular exam.