<div dir="ltr"><div>Why do you believe this test has a fundamental error versus TAC testing? It is a different test, no more, no less.</div><div><br></div><div>To play devil's advocate, one could claim that Teller Acuity Cards lack ecological validity because they do not present contours and objects, which are more important to the visual system during daily living than sinusoidal or square-wave gratings. That said performance on this test and TAC ought to correlate and if this new test has other benefits (e.g, faster/easier to administer, cheaper and more available to purchase, and so on...) and has appropriate age-norms for the population being screened then might it not be an advance on traditional TAC testing?</div><div><br></div><div>Best,</div><div><br></div><div>C </div><div><br></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Feb 13, 2020 at 9:36 AM Meindert de Vries <<a href="mailto:meindertdevries@visio.org">meindertdevries@visio.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div class="gmail-m_2483462140074653238WordSection1">
<p class="MsoNormal"><span lang="EN-US">Dear members ,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Since 1992 I </span><span lang="EN-GB">work</span><span lang="EN-US"> for Visio, an institution the helps visually
</span><span lang="EN-GB">impaired</span><span lang="EN-GB"> </span><span lang="EN-GB">people</span><span lang="EN-US">. We have always been using the Teller Acuity Cards to determine the visual acuity in children.
<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">A new test has been presented on the scene, proposing to replace the Teller Acuity cards, because the TAC are expensive and sometime difficult to get. I enclose an example picture of the new cards.
<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">From my perspective and knowledge they have made some fundamental errors<u></u><u></u></span></p>
<p class="gmail-m_2483462140074653238MsoListParagraph"><u></u><span lang="EN-US"><span>1.<span style="font:7pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">The test seems ambiguous to me, because both object recognition part of our visual system as well as the much ‘lower” detection part of our visual system is triggered by this stimulus<u></u><u></u></span></p>
<p class="gmail-m_2483462140074653238MsoListParagraph"><u></u><span lang="EN-US"><span>2.<span style="font:7pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">The spatial frequency content of these stimuli (checkerboard patterns with a distinctive contour) is in the Fourier domain essentially different from the TAC bar patterns without a contour; nevertheless the
same cycl/cm are used. <u></u><u></u></span></p>
<p class="gmail-m_2483462140074653238MsoListParagraph"><u></u><span lang="EN-US"><span>3.<span style="font:7pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">In addition to point 2: I think that the contour is a much stronger stimulus than the checkerboards.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Could anybody reflect on this ?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span>Most kindley,<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:12pt">drs. M.J. de Vries 69024716001<u></u><u></u></span></b></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
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