I first present three philosophical theories on blurriness. The first theory says that seeing x blurrily is unlike seeing x as fuzzy; the second theory says that seeing x blurrily is seeing x as fuzzy; the third theory says that seeing x blurrily is seeing x without sufficient information on some of its surface visual details. I endorse the third theory. Then, I address the question whether blurriness can be considered a perceptual illusion. I argue that it can be a perceptual illusion and hence can involve some kind of perceptual error, without being a case of mismatch between perceptual content and things out there. In fact, I believe that the popular idea that illusions are mismatches between perceptual content and things out there is seriously flawed. In defending my claims, I rely on Kevin Mulligan's theory on visual awareness and primitive certainty.