What did you find out? From what I read, it's controversial and I don't know what to think of it. I tutored reading last year and tried putting colored overlays on passages of kids who had tracking issues. They all said the overlays were helpful, but only one boy showed a dramatic difference in reading fluency. He said that without the overlay, it looked like there were two layers of print and the colors made the words easier to see. Now my son has some vision issues (eye tracking). His OT suggested we try colored overlays, saying that they activate both the rods and the cones.