I have a student with Irlen Syndrome and his mom has sent him to school without his glasses for 4 months now. So I started giving him colored overlays. What I did was bought some cheap folders like this http://www.target.com/p/up-up-binder-pocket/-/A... He slides whatever he is reading into this pocket and it helps a lot. I also cut one up for him to use with text books. Try this before investing in the Dr. if it seems to help then go ahead with the Dr. as this student prefers his glasses over the overlays. And note that not all kids have the same color preference so I'd try several different colors. The student in my class prefers purple. We also copy all his work onto purple paper so that overlays are not necessary at times.

I have one student every school year that blue overlays work so well for them.
I have been a teacher for 28 years and this is becoming more and more a common practice.

Colored filters sometimes do help with people with dyslexia, you can get filter book marks at a teacher store...i haven't any experience with the lenses and don't anyone who found then helpful

I'd never heard of this but was curious because one of little guys processes visual information significantly slower than his brother. Information from someone who wasn't selling the product was pretty slim but I found this article -
http://www.scholastic.com/teachers/top-teaching...
I might try it if our school wanted to provide them but I'm not sure I would put my own money into it on the off chance it might do something.