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Re: Color contrast in links -- is it important?


From: Phil Teare
Date: Apr 22, 2007 10:30AM

Hi Emma

> Relating this comment back to the point about some users finding too
> much contrast difficult, does any one have any statistics about the
> numbers of users who fall into these groups - and also what other aids
> they might be using. (I know a friend's child had difficulty reading,
> it wasn't dyslexia, nor irlen lens sydrome; they weren't quite sure
> exactly what. Whatever the problem, and it doesn't really matter,
> tinted glasses helped him - he used them for everything; PC, books
> etc. )
These figures are approx and sometimes mid points between two popular

In the UK approximately 5% of the entire population are severely effected by
dyslexia, 10% of the population is dyslexic to a degree that they would be
clearly diagnosed as such, and thereby acquire legal rights for
accomodation. The tail drags on for another 5-10% of the population.

80%+ of dyslexics have some form of visual 'lag' which is or is similar to

Some (but few) have Irlens but no dyslexia. There's a great deal of
comorbidity, but they are different conditions.

50%+ of those incarcerated have dyslexia! Think of the social cost of not
accommodating their differences in society. I once estimated it at more than
£1bn p.a. in the UK. The DI then backed this estimate.

Compare these figures to those for v.i. users in the general populus and we
can see that the issues is certainly not less significant than v.i. Clearly
quantifying social need is subjective at best, but like I say, I hope you'd
agree that this is a very important issue that is not mentioned in the WACG
at all.

High and low contrast options ought to be advised by the standards and
guidlines IMNSHO

I could poss dig out references for the above figures, but you'll find them
as quickly as me, with google. For excellent work in this area look for Prof
Jon Stein's work at Oxford (I believe he headed an investigation funded by
Tintavision - I know for a fact that here was perfectly impartial,
disagreeing with a great many of Tintavision's assumptions in his finding,
by finding some very interesting fact in the process, including a multi
sensory deficit at discerning information at around 2hz, even in touch,
amongst dyslexic individuals).

Hope this helps,

Phil Teare,
Technical Director & Lead Developer,
http://www.talklets.com from Textic Ltd.
(44) [0] 77 68479904