'scuse me for butting in, but here's my reply to another poster with a similar question about coloured overlays and coloured glasses:-
Have just googled the glasses- sounds interesting but I fear that my son doesn't have visual dyslexia - will look into it though
The eye condition that is helped by using a coloured overlay or glasses is called Irlen Syndrome
. But a dyslexic doesn't necessarily have Irlens's and someone with Irlen's may not have dyslexia!
My DD2 has poor vision and we have had her eyes tested at our local Specsavers every 6 months since she was 3 (she's now 12). When the school Educational Psychologist found out DD2 was dylexic she encouraged us to request through Specsavers an appointment with an Optometrist.
The Optometrist visited only one afternoon a month and we had to wait three months to have an appointment of about an hour which cost Â£25. He tested DD for Irlen syndrome by asking her to read a passage from a book. He then laid many different coloured overlays on the book to find out if any of the colours helped her see the words better.
In DD's case she didn't have Irlens but he found another problem in that her eyes focus at different lengths and independently of each other!
If you have never had your son's eyes tested it might be worthwhile having them tested, or if he already does wear glasses, ask his opticians how to get an appointment with an Optometrist.
Have a shufti at this website too, it's very informative 'irlenuk.com'
Edited to add:- If a coloured overlay is useful, it is possible to have a block of plain writing paper in that colour for the child to use because obviously you cannot write underneath the overlay!