[visionlist] Teller acuity cards

mayerl at neco.edu mayerl at neco.edu
Mon Jul 27 10:47:05 -04 2020

Regarding the stream on the new "acuity" test figures shown by DeVries.
Interesting comments!

Angie's comments bring up the issue about whether a specific shape is
perceived similarly at threshold vs. suprathreshld levels. But if this is a
detection task, why does that matter? However, if the overall areas of the
shapes differ which appears so from the photos, this should invalidate a
presumption of equivalent detection at threshold. Also there is problem in
using different shapes in that infants and children may have preferences for
certain shapes, for example, those that they recognize. Answering Chris
Taylor's advocacy for a more ecologically valid stimulus than gratings, this
is a good concern. However, the challenges of designing such a test that
meets all the requirements for stimulus properties and consistency and
validity seem daunting.  Designing a test of form or shape discrimination
appropriate for infants/children could have clinical utility for assessing
risk of cerebral/cortical visual impairment. I can't imagine, however, that
the test designt could be done simply, using a preferential looking
paradigm. Maybe, I'm wrong and there's already such a test.

Also, isn't it the case that spatial frequency power of a checkerboard is at
the diagonal? Wonder if the designers calculated cy/cm using check width or
the diagonal? 


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