iPad 1 and iPad 2 are both great for reading.
P.S. how do you read on a computer display then? Many are of a lower pixel density than iPad.
Actually, if you compare an iPhone 3GS with an iPhone 4, the increased pixel density makes it's biggest impact with text. You notice the increased resolution a lot more in iBooks than when viewing photos or video. The sharpness of the text makes a big difference in how easy it is to read.
Definitely will reduce eyestrain.
CaN an opthalmologist verify this?
I own several iPhone 4 and several Pad 2, i do not see much of a difference, since it is comparing a small screen vs a large screen, I think it would become a placebo effect if iPad 3 has retina display, it will just be our mind making some tricks on us... Not to mention, there has been studies report that show the retina display on iPhone 4 isn't really "retina display" it was more a marketing hype.
Things that can cause eye strain include weird contrast levels, displays that are too bright, high levels of reflectivity, and viewing something that lacks acutance for an extended period of time. A higher resolution screen basically affects one of these things. When your eyes lack something sharp to focus on, it can tire them out over time.
For books, like on the Kindle app and iBooks, text will likely be noticeably smoother. But, to be honest, I'm fine with the current screen for this purpose.
I think the biggest improvement will be in portrait mode surfing websites. Text is still sort of fuzzy and pixelated on the current iPads in portrait mode before zooming in.
I own several iPhone 4 and several Pad 2, i do not see much of a difference, since it is comparing a small screen vs a large screen, I think it would become a placebo effect if iPad 3 has retina display, it will just be our mind making some tricks on us... Not to mention, there has been studies report that show the retina display on iPhone 4 isn't really "retina display" it was more a marketing hype.