Here are a couple of round-ups of studies:

https://bigelowandholmes.typepad.com/bigelow-holmes/2014/11/...

https://www.truthorfiction.com/dyslexie-font/

This study looked at OpenDyslexic, and found subjects preferred Verdana and Arial:

http://dyslexiahelp.umich.edu/sites/default/files/good_fonts...

Whether sans serif or serif fonts are more legible remains contested:

http://alexpoole.info/blog/which-are-more-legible-serif-or-s...