When it comes to user-interface design, accessibility and usability are one of the most important principles to keep in mind.

People with dyslexia often unconsciously switch, rotate and mirror letters in their minds and traditional typefaces make this symptom of dyslexia worse. Traditional typefaces base some letter designs on others (like b and d), inadvertently creating 'twin letters' for people with dyslexia.

Lead Designer Branding Product Management Developement January 2015 iOS 8