Are high-redshift quasars blurry?

It has been suggested that the fuzzy nature of spacetime at the Planck scale may cause light waves to lose phase coherence, and if severe enough this could blur images of distant pointlike sources sufficiently that they do not form an Airy pattern at the focal plane of a telescope. Blurring this dramatic has already been observationally ruled out by images from Hubble Space Telescope (HST), but I show that the underlying phenomenon could still be stronger than previously considered. It is harder to detect, which may explain why it has gone unseen. Asystematic search is made in archival HST images of among the quasars with the highest known redshifts. Planck-scale-induced blurring may be evident, but this could be confused with partially resolved sources.