FOR INFORMATION on random dot stereograms and Magic Eye 3D Illusions, please reference information on this website; especially the faq page you’re reading.
For some interesting information on the use of Magic Eye by vision care specialists please consult the Magic Eye information of Dr. Marc Grossman on the vision3d website. The Book, Magic Eye Beyond 3D: Improve Your Vision, by Magic Eye and Doctor Grossman is also an excellent source of information.