There is an issue to be discussed... what is meant by dyslexia? (THAT WAS RHETORICAL....)
The term dyslexia, from its Greek roots, means (approximately) "has trouble with words" - but the usual explanation is that people with dyslexia see the letters backwards. That actually CANNOT be the real definition because it would require people to SELECTIVELY see letters backwards but everything else forwards. Further, experiments have shown that if you wear inverting goggles for a couple of days, your brain automatically adjusts to the inversion and suddenly you see everything normally. So no, whatever it is, it is NOT that people see words backwards. I once had a long argument with a school teacher who had this fixation in her head that it was a "sees words backwards" problem. But no - it isn't that.
Here's a link to the definitions of the main types of dyslexia:
Below are some of the different terms that are often used when talking about the various different types and combinations of underlying skill difficulties associated with poor reading. The more...
www.speechie.co.nz
The most common kind, phonological dyslexia, can actually be traced back to a problem with eye-ear coordination and the fact that the traditional way of learning how to read involves learning how to "sound out" the words. For people whose eyes and ears don't work together, this becomes a serious problem. Someone did computer research on slowing down words spoken too quickly and found that dyslexics of the phonological type did better with a computerized word decelerator that allowed them to better hear the parts of the word in proper acoustic order.
Unfortunately, some dyslexia types are related to the mental ability to recognize whole images of words solely by sight. This is the visual dyslexia or dyseidetic dyslexia. The linked article gives some decent explanations.
@gemma-the-husky - your original question: Is dylexia real? .... is answered by this site. Yes, real enough to have four major variations.
