You can treat Irlen by filtering light with colored overlays... or with specially tinted glasses and contacts. See the How to get tested page for more info on how to get your own lenses or overlays.
There are 2 levels of treatment:
Overlays are colored plastic sheets you can put over anything you’re reading. You can set up an appointment with an Irlen tester to see if you have Irlen, and at the end of the test your tester will help you find the specific color or combination of colors that works for you so you can read more easily and comfortably.
The problem with overlays is that they only help with stuff that’s on a page right in front of you. If you have problems with headaches, night driving or depth perception you’ll want some Irlen lenses.
Irlen lenses are specially tinted glasses. They're tinted to the exact color that will help you with your Irlen symptoms. Different people need different colors of glasses; it's not a one-color-fits-all kind of deal. To get lenses you go to an Irlen diagnostician. There’s just about endless combinations of possible colors and the diagnostician will help you find yours. Mine are a combination of 2 layers of blue and a blue-gray. After you find your color you send in a pair of everyday, ordinary glasses to the Irlen labs and they tint them for you. They'll send them back to you in the mail.
Irlen contacts work the same way as Irlen lenses but, of course, they're contacts. You can request just the pupil area of the contact to be tinted. Then they don't look tinted at all. The whole process for getting contacts is exactly the same as with the lenses, above.