Retinal complications were unreported in the study, but, for context, the patient who developed the bull's eye maculopathy had lower CP levels (0.9 μmol/l) than almost all of the HH patients described by Cairo et al. (the lowest of which was also around 0.9 μmol/l) (Bellsmith et al., 2020; Cairo et al., 2001). Here, CP is linked to Bull's eye maculopathy.