This is one of the first things you learn in any Web accessibility class:
"Centered or justified longer pieces of text can be hard to read as well. Justified text adds space in between words that can cause rivers of white space through lines making reading difficult for some users with dyslexia. If hyphenation is supported this can reduce this effect but hyphenated words can be a barrier for many readers."
https://www.w3.org/WAI/tutorials/page-structure/styling/#tex...
"Sometimes full justification makes reading more difficult because extra space between words causes “rivers of white” making it difficult to track along a line of text, or less space between words makes it difficult to distinguish separate words."
https://w3c.github.io/low-vision-a11y-tf/requirements.html#j...
"Many people with cognitive disabilities have a great deal of trouble with blocks of text that are justified (aligned to both the left and the right margins). The spaces between words create "rivers of white" running down the page, which can make the text difficult for some people to read. This failure describes situations where this confusing text layout occurs. The best way to avoid this problem is not to create text layout that is fully justified."
https://www.w3.org/TR/WCAG20-TECHS/G169.html
"Fully justifying text can also present problems for people with dyslexia, where the large uneven spaces between words and sometimes letters within words can create what’s been termed “rivers of white” that run down the page and also make the line of print hard to follow. Readers find it more difficult to find the end of sentences and can repeatedly lose their place."
http://mediaaccess.org.au/accessibledocumentservice/2015/08/...
"A lot of people seem to love justified text, arguing that it contributes to the feeling of a more consistent page layout. From a strictly accessibility-focused perspective however, justified text creates large uneven spaces between letters and words that make reading a little more difficult for all users, and even more so for users with dyslexia."
https://dboudreau.tumblr.com/post/84344543792/avoid-justifie...
"Centered or justified longer pieces of text can be hard to read as well. Justified text adds space in between words that can cause rivers of white space through lines making reading difficult for some users with dyslexia. If hyphenation is supported this can reduce this effect but hyphenated words can be a barrier for many readers." https://www.w3.org/WAI/tutorials/page-structure/styling/#tex...
"Sometimes full justification makes reading more difficult because extra space between words causes “rivers of white” making it difficult to track along a line of text, or less space between words makes it difficult to distinguish separate words." https://w3c.github.io/low-vision-a11y-tf/requirements.html#j...
"Many people with cognitive disabilities have a great deal of trouble with blocks of text that are justified (aligned to both the left and the right margins). The spaces between words create "rivers of white" running down the page, which can make the text difficult for some people to read. This failure describes situations where this confusing text layout occurs. The best way to avoid this problem is not to create text layout that is fully justified." https://www.w3.org/TR/WCAG20-TECHS/G169.html
"Fully justifying text can also present problems for people with dyslexia, where the large uneven spaces between words and sometimes letters within words can create what’s been termed “rivers of white” that run down the page and also make the line of print hard to follow. Readers find it more difficult to find the end of sentences and can repeatedly lose their place." http://mediaaccess.org.au/accessibledocumentservice/2015/08/...
"A lot of people seem to love justified text, arguing that it contributes to the feeling of a more consistent page layout. From a strictly accessibility-focused perspective however, justified text creates large uneven spaces between letters and words that make reading a little more difficult for all users, and even more so for users with dyslexia." https://dboudreau.tumblr.com/post/84344543792/avoid-justifie...