She could be referring to Irlen Syndrome which deals with light sensitivity. You can visit the website at www.irlen.com/ to view sample distortions. The website provides lots of great information and might give you some answers.
Irlen Syndrome, which is also known as Scotopic Sensitivity Syndrome (SSS), results from the how brain handles visual information. Children with this syndrome typically experience distortions and headaches when reading. As this can lead to learning disorders and frustration with school it is important that your child seeks treatment immediately. If your child is suffering from these types of symptoms please see your doctor and inform them that you think your child may have the Irlen Syndrome.