In AR, the viewing angle of the text is not always straight in front of the user as compared to conventional screens. The text can be present in the environment around the user to make it more immersive; this introduces the issue of perspective distortion in the text.
Viewing text at an angle sometimes merges the adjacent strokes and affects the visibility of counters in narrow typefaces making it very hard to distinguish between letters. In traffic signs, information is parsed similarly, at an acute angle. However, the challenge in AR is more complicated since the text presented can be paragraphs as opposed to few words in signages.
In condensed typefaces, letters become too narrow when viewed at an angle. Which brings the vertical strokes together and causes legibility issues.
Condensed typefaces perform poorly in cases of distance viewing too.
Wider typefaces perform better in a variety of use cases. But they occupy more space hence fitting a lesser number of characters per line.
Letter shapes with a wider body also reduce the effect of halation and irradiation since the space between the strokes is preserved.