Over the lst few months I have learned a lot about many things, including visual stress. Visual stress is said to possibly affect up to one in 5 of us to some degree, and can make accessing any sort of text very difficult. I gave a talk on this at TMHighland, and have produced a screencast of the talk. Click the link below to see a demo video showing some of the types of distortions that are experienced.
Visual Stress – Sample distortions