ThackeryBinks
You might find the onyx book ereader android tablets useful. They use e-ink screens, which prevents using them for video, and can make web browsing tricky - but are great for anything primarily text based and about as eye friendly as it gets. I'm thinking of getting one to use for word processing (I'm a student). They are very pricey though for what they are.
Might also be worth waiting around for amazon to release an electrowetting kindle/tablet. Its a new technology so can't say how eye friendly it will be, its in the same vein as e-ink but has good enough colour/refresh rates to display video. It doesn't use polarising filters, and doesn't need a backlight to work - so its a good bet it'll be easier on the eyes than lcd/amoled tablets.