Do People with Dyslexia Have Trouble Controlling Their Eyes?

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Susan Godsland
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Do People with Dyslexia Have Trouble Controlling Their Eyes?

Post by Susan Godsland » Mon May 22, 2006 6:29 pm

Hutzler, F., Kronbichler, M., Jacobs, A.M., & Wimmer, H. (2006). Perhaps correlational but not causal: No effect of dyslexic readers’ magnocellular system on their eye movements during reading. Neuropsychologia, 44, 637–648.

Abstract

During reading, dyslexic readers exhibit more and longer fixations and a higher percentage of regressions than normal readers. It is still a matter of debate, whether these divergent eye movement patterns of dyslexic readers reflect an underlying problem in word processing or whether they are – as the proponents of the magnocellular deficit hypothesis claim – associated with deficient visual perception that is causal for dyslexia. To overcome problems in the empirical linkage of the magnocellular theory with reading, a string processing task is presented that poses similar demands on visual perception (in terms of letter identification) and oculomotor control as reading does. Two experiments revealed no differences in the eye movement patterns of dyslexic and control readers performing this task. Furthermore, no relationship between the functionality of the participants’ magnocellular system assessed by the coherent motion task and string processing were found. The perceptual and oculomotor demands required during string processing were functionally equivalent to those during reading and the presented consonant strings had similar visual characteristics as reading material. Thus, a strong inference can be drawn: Dyslexic readers do not seem to have difficulties with the accurate perception of letters and the control of their eye movements during reading – their reading difficulties therefore cannot be explained in terms of oculomotor and visuo-perceptual problems.
http://www.iapsych.com/articles/hutzler2006.pdf

JIM CURRAN
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Visual problems

Post by JIM CURRAN » Mon May 22, 2006 8:25 pm

Most, if not all of the research that I have read points to reading problems being phonologically based but of course that doesn’t rule out visual type problems that some children might also have.
Rod Everson who use to post on readbygrade3 had some interesting things to say on visual problems.

Now, as to your vision question:

There are no short answers to this. I basically think that most kids
who fail to learn to read on schedule have vision problems of the nature
I've been discussing. Sometimes they resolve independently at age 5-7, and
this explains the kid, particularly the boy, who suddenly begins to "get
it." They can finally make visual sense of print.

I believe that the essence of the vision problem is an inability to
converge both eyes simultaneously on a single point, time after time,
sustaining the effort as we must do when we read. Essentially, these kids
are getting two simultaneous images and can't sort them out. Sort of like
trying to read with your eyes slightly crossed.

Optometrists can demonstrate that many kids begin to demonstrate what's
termed "suppression," and particularly "alternating suppression" of vision
when they have poor convergence skills (another term for poor convergence
is poor "binocularity," i.e. both eyes are not functioning together as a
team.) Anyway, suppression is simply the brain picking and choosing
between right-eye and left-eye input. The brain "suppresses" the image
from one eye so that only one single image is being interpreted. (It can
be demonstrated in a fairly straightforward way that this does actually
occur.) What actually seems to happen though is "alternating suppression"
which means that the brain suppresses first the right-eye image and then
the left-eye image in an alternating sequence.

I believe that "alternating suppression" is an attempt by the brain to
train the eyes to work together. That is, the brain gets a double image,
can't interpret it, suppresses the image from one eye, interprets what it
receives, shuts down suppression, gets another mixed message, suppresses
the other eye, interprets correctly, etc., etc. The logical reason for the
alternation is that both eyes stay in the game. When the brain gives up in
this attempt, the suppression moves to one eye only, acuity begins to dim
in the suppressed eye, and the eye even sometimes begins to wander,
resulting in what is commonly called "lazy eye."

Kids undergoing this process simply can't learn to read comfortably.
You may be able to teach them the underlying phonics of reading,
particularly if you stick to good-sized print, but they won't read
comfortably, so they won't do the practicing that the normal child does.

In remediation, the ideal candidate is one who didn't learn to read
because of visual confusion, but whose vision problems have resolved and
they now just don't know how to read. With this kids, a good reading
method, like **, appears to work wonders. In my case, I see
many kids who have undergone recent vision therapy, can now see and
interpret what they couldn't before, and are therefore easy
clients.....they learn quickly and more importantly, they are not
uncomfortable, so they find that they actually like to read once they can
understand the code.

At the back of my workbook is a vision checklist. It's usage is
described in the instruction manual. It describes the symptoms that I have
come to consider telling and I would suggest you look it over next. Then
do some reading on vision therapy. One website that is pretty good in this
regard is childrensvision.com.

The final step is to find a good developmental optometrist in your area
(that may be difficult) and establish a relationship. This will enable you
to discuss these vision problems with someone who addresses them and you
should also be able to then find parents who can tell you the difference
that vision therapy has made in some cases.

One final point. Some kids just learn to read incorrectly. They may
have had a vision problem which either resolved on its own or was
remediated by vision therapy and had a harder time than other kids when the
poor instruction was being administered. The kids who could see well
figured it all out in spite of the poor instructional techniques, but the
kid with the vision problems actually listened to the teacher and is using
the poor instruction. These kids can resemble kids with vision problems
because they also resist reading (because they can't make sense of print
due to the type of instruction they received and the strategies that
resulted) and because they make many mistakes that seem inexplicable.
Basically, these kids are the guessers, or part-word guessers, and at times
you can almost convince yourself that they just must not be able to see
what they are reading. In fact, they just aren't looking at the code.
They are instead looking at a letter and the length of the word and
guessing, or looking at a word like "then" and initiating some process like
"Let's see now, that's one of those "there/where/then/when" words...which
one is it? 'When' fits, so I'll go with that for now." In other words,
they aren't decoding, they're trying to simply remember which word it is
and using a very poor set of strategies to do so. These kids can be real
challenges sometimes, and it's a little too easy to simply conclude that
their vision is at fault.

lks
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Post by lks » Tue May 23, 2006 6:16 am


CuriousMum
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Post by CuriousMum » Tue May 23, 2006 4:48 pm

My older son, nearly 8, is not at all 'dyslexic' in the popularly understood sense of the word, as he has a reading age over 5 years above his chronological age and is also a strong speller. However, he still, when reading aloud, loses his place frequently and often substitutes a word from the line below, particularly near the end of the lines. He is reading novels now, sometimes with quite small print, and he still will say a book is hard or easy based on the size of its print, not the vocabulary.

Is this still developmentally typical or should I get him checked over by an optometrist?

I wonder more since my 4 year old doesn't have the same kind of tracking problems, and can actually manage a whole page of a book like A A Milne's Winnie-the-Pooh without getting lost.

g.carter
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Post by g.carter » Tue May 23, 2006 7:33 pm

C. M. suggest that you make enquiries via www.dyslexic.org.uk or google Professor John Stein at Magdalen College,Oxford. You ought to start at the top and find out if there is anyone suitably trained in your area - you can waste an awful lot of money otherwise....g.

CuriousMum
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Post by CuriousMum » Tue May 23, 2006 11:35 pm

Thanks, G. I'll have a look at the link. I was chatting about it to the optician the other week, but wasn't convinced that he really understood what I was on about.

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