OpenDyslexic is a free typeface/font designed to mitigate some of the common reading errors caused by dyslexia. The benefit has been questioned in scientific studies. The typeface was created by Abelardo Gonzalez, who released it through an open-source license. The design is based on DejaVu Sans, also an open-source font. Like many dyslexia-intervention typefaces, most notably Dyslexie, OpenDyslexic adds to dyslexia research and is a reading aid. It is not a cure for dyslexia. The typeface includes regular, bold, italic, bold-italic, and monospaced font styles. In 2012, Gonzalez explained his motivation to the BBC: "I had seen similar fonts, but at the time they were completely unaffordable and so impractical as far as costs go." Two studies have investigated the effect of specialized fonts used with students with dyslexia. Rello and Baeza-Yates measured eye-tracking recordings of Spanish readers with dyslexia and found that OpenDyslexic did not significantly improve reading time nor shorten eye fixation. In her master's thesis, Leeuw compared Arial and Dyslexie with 21 Dutch students with dyslexia and found Dyslexie did not lead to faster reading, but may help with some dyslexic-related errors. The British Dyslexia Association recommend “plain, evenly spaced sans serif font such as Arial and Comic Sans. Alternatives include Verdana, Tahoma, Century Gothic, Trebuchet” instead of fonts like OpenDyslexic or Dyslexie. The typeface is currently an optional choice on many websites and formats, including Wikipedia, Instapaper, Kobo eReader, Amazon Kindle Paperwhite, a few children's books, and at least one imprint of classic literature. There is also a Google Chrome extension available, which was developed by Abelardo Gonzalez and Robert James Gabriel. It is also part of the "dyslexia-friendly mode" in Oswald Foundation's web accessibility products. There are other typefaces and fonts that have been linked to benefits for people with dyslexia including: BBC Reith, Comic Sans, Dyslexie, FS Me, Sassoon and Sylexiad.