Thread Subject: Re: 21(k) and 22(j) Flashing and blinking

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From: Jim Tobias
Date: Tue, Jan 16 2007 5:08 PM

Andi wrote:
"When we discussed 21(k) and 22(j), we liked the idea that WCAG 2.0 defines
a minimum size area of flashing that is subject to the prohibited frequency
range. A blinking text caret, for example, is too small to cause a problem
no matter what frequency it it blinking at."

Is there any authoritative clinical guidance that we can point to? We've
gotten
so much second-hand info on this issue over the years, but nothing from a
citable
source. We should be concerned about that.

I appreciate your proposal of a standard that uses pixels, but my guess is
that the
seizures are triggered when brightness and visual angle reach a threshold.
That is,
a device held closer to the eyes is more "dangerous" than one held further
away. There
are probably other factors involved.

Since this issue applies to several product categories, we should try to
write a generic
standard if we can.

If someone can point me towards some clinical research resources (especially
a person), I
will follow up.


Jim Tobias
Inclusive Technologies
+1.732.441.0831 v/tty
+1.908.907.2387 mobile
skype jimtobias

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