It says what you are doing. I know a blind person with a touch screen phone lol I asked the same thing. She showed me. It is an app that says what ever you're touching on the screen.
Don't do it though!!! It's almost impossible to turn off. I did it ages ago on my iPad and I had to take it to IT to turn it off and it's so annoying, too.
Even than, it would depend. He could probably read something written by hand on an ordinary sheet of paper, and reading something that has been printed would be even harder but possible if it's purely print on paper like a book. So if it's printed on a background image, like a label, than he wouldn't be able to read it. Furthermore, he wouldn't be able to read something printed on glossy paper (or surface), like a flyer, because there aren't any different textures, just one smooth page. So really, it depends on how it's written and on what.
You're right. He can read ink even if it's on a flat surface. He wouldn't be able to read anything laminated but with his vision which in comics is described as a kind of radar or in the show he sees a world on fire he would be able to make out what the words said.
But to see a world on fire or use radar, the objects he's "seeing" need to have depth, which words on paper, either printed or hand written, don't have because their depth is so minuscule it's negligible. The only way for him to read would be through texture as previously discussed.
I'm not saying he could read read it with his vision I'm saying he could probably vaguely make out the words but mostly he would have to touch it. And phones have radiation so in my theory because they do he can probably see what he's doing on it.
From a realistic and scientific point of view, that doesn't make any sens. I'm pretty certain radiation doesn't work that way, and even if it did, there is no way he could sens it since his natural senses (touch, smell, hearing, taste) are the ones that are heightened, and sensing radiation his not humanly possible. On another note, phones don't emit radiation, not to mention that radiation is incredibly dangerous to humans. Phones, however, do emit radio-frequencies, and other types of waves, such has light-waves (that are captured by the eye and allow us to see). Since Matt is blind, he can't capture light-waves, leaving only sound-waves (captured by the inner-ear) since the human organism isn't adapted to capture other types of frequencies.
Furthermore, it clearly states in the show that he cannot see screens. In one episode, he finds a phone that contains a text message stating the locations of the Russian mob. He has to take that phone to Claire so that she can read it to him, because he can't see.
Also, in the TV series, he doesn't use radar to make up his world of fire, but rather sound. (This is especially touched upon in season 2, but I don't want to expand on that to much since I don't want to spoil it for anybody.) So from the TV series point of view, there is absolutely no way for him to "see" what's on the screen.
It's mostly by sound, smell, perhaps the taste of the air and slight shifts in temperature.
But thank you for arguing with me! It was interesting, as well as fun, to get to finally discuss this with someone else :)
"Shit shit! shut the fuck up, siri!"
On the iPod/iPhone: Settings>General>Accessibility>VoiceOver
Also, in the TV series, he doesn't use radar to make up his world of fire, but rather sound. (This is especially touched upon in season 2, but I don't want to expand on that to much since I don't want to spoil it for anybody.) So from the TV series point of view, there is absolutely no way for him to "see" what's on the screen.
But thank you for arguing with me! It was interesting, as well as fun, to get to finally discuss this with someone else :)