The Irlen Method
has been used for over 30 years to identify and help people with a type of processing problem called Irlen Syndrome, formerly known as Scotopic Sensitivity Syndrome (SSS). Irlen Syndrome is not an optical problem. It is a problem with the brain's ability to process visual information. This problem tends to run in families and is not currently identified by other standardized educational or medical tests.
For more information watch this short video of sample print distortions: