[visionlist] Teller Acuity Cards

[Meindert de Vries]

Dear members ,

Since 1992 I work for Visio, an institution the helps visually impaired people. We have always been using the Teller Acuity Cards to determine the visual acuity in children.
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.

>From my perspective and knowledge they have made some fundamental errors

1.       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

2.       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.

3.       In addition to point 2: I think that the contour is a much stronger stimulus than the checkerboards.

Could anybody reflect on this ?

Most kindley,


drs. M.J. de Vries 69024716001

Revalidatieoogarts
Koninklijke Visio Noord-West Nederland Revalidatie & Advies
Hettenheuvelweg 41-43 1101 BM Amsterdam
T 088 585 57 23/585 57 00   M 0031 (0)6 50 51 86 13

Kinderoogarts-Ophthalmogenetica-Strabologie-Revalidatie
Universitair Ziekenhuis Antwerpen  afdeling ophthalmologie
Wilrijkstraat 10
2650 Edegem
T +32 3 821 30 00 M +31 6 50518613





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