Tinted lenses have greater applicability because they help students work out problems directly on math pages without having to deal with the overlay. They help taking tests and notes, reading chalkboards, working at computers and reading longer under flourescent lights.
“Reading by the Colors” Updated edition by Helen Irlen page 24,used with permission by the author
I would also point out that the lenses can assist in perception of the total environment. They can help so much more than reading. One example is in prevention of migraine headaches. Another is in improved perception leading to enhanced depth of field perception which can be amazing. I am still stunned by how trees along the road stand out from the trees in the background. I almost drove off US-23 when I first encountered this with a tree standing in the middle of a field. It just leapt out at me. 