I never believed the readability claims of pro-serif folk. It struck me long ago that “comic” was the most readable font in the world and I create all my course material in that font. My students mock me. What would be a valid test of font readability? Data gained from dyslexic studies might be applicable only to dyslexics. It might be that for 90% of the population, Times New Roman (or some such serif font) is as easy to read as Ariel (or some such sans-serif font). Could we measure how much brain activity it takes or how many calories are burned? Could one font lead to more fatigue? Burt's statements about the supposed superiority of serif fonts turned out to be nothing more than idle conjecture dressed up to sound scientific.
Word shape is no longer a viable model of word recognition. The bulk of scientific evidence says that we recognize a word’s component letters, then use that visual information to recognize a word.
When we are trained to read in our native language, most reading is essentially sight reading or memorization of words. After sufficient reading, we grow to recognize most words. My guess is that font has no impact on readability, but some fonts might take slightly more work, some slightly less. Meanwhile, this particular blogger (Kas Thomas) has some interesting posts.