I'm not sure which word I should use, because he also says that some of the richest people in the US cannot read or write. Maybe this was meant as a joke, but who knows. Maybe there actually is some truth to it, and he is part of it. But, we can go with dyslexia.

But, what about the glasses part?

A billionaire that can't read? Yeah that is obscene.

He reads from the teleprompter all the time. Doesn't that count as reading?

Trump has a Master degree from an Ivy League University.

Trump says he doesn't.

While it's all fun&games, fact remains, that Trump has an Ivy League Master, turned his father's business into a Multi-Billion-Dollar Empire, has a loving family and just won the Presidency against the most established politician/media machine ever. How many people can claim a similar level of accomplishment? It reminds me of people calling the last Pres Odumbo or W an idiot with demonstrable evidence to the opposite.

I'd lean less towards difficulty reading, and more towards disinterest and possibly a short attention span. I.e. I'd imagine that he might have the same literacy level as anyone who's gone through school but reads virtually nothing outside what's required in school; nothing for recreation in other words. Now, might it lead to a certain feeling of 'rust?' That he can't read as quickly or effortlessly as someone who spends a great deal of time doing so, and so avoids anything too 'meaty?' Very possible.

His Black History Month speech was kind of telling, if you watched his eyes. Every time it was something about Black History, he'd read from the paper, at times picking it up outright. Occasional glance away for emphasis, but generally for just a word or two. But then he'd talk about his campaign, people who helped him in his campaign fake news, Fox being nice to him, etc and for the most part his eyes would off the paper. Excellent example being where his eyes were when he was talking about Martin Luther King Jr. vs. when he was talking about the incident with the bust of MLK's head. xP

Guy can read, he just seems to dislike it.

Samantha Bee was being sarcastic. At the very beginning of the video, she says, 

“After seeing how easy and fun it is to take random scraps of evidence and spin them into ridiculous conspiracy theories, we decided to try it ourselves”

She was making fun of all those internet articles claiming that Hillary was wearing secret earpieces during the debates or had syphilis and other ludicrous arguments by taking tiny, insignicant bits of evidence and turning them into an equally ludicrous argument against Trump. 

I think he's probably an undiagnosed dyslexic. My father-in-law is basically the same. Very intelligent person, knowledgable, creative. But hates to read because he is dyslexic but it was never diagnosed when he was a child and so he never got the educational support dyslexics need.

I would not be surprised at all if DJT is the same.

So illiterate? No. Has a reading disorder, that makes reading an unpleasent and difficult task? Probably. Makes him unsuited to be president because of dyslexia? No.

Below normal eyesight too maybe.

Bad eyesight sounds much more likely and logical. Conspiracy theorists really like to grasp at straws.