SERPINC1 and spondylo-ocular syndrome: Acknowledged limitations include the small sample size of patients receiving preventive DF, the use of antithrombin III level as a severity criterion of SOS, which could have overestimated the incidence of S/VS SOS, and the use of the Baltimore and modified Seattle criteria to diagnose SOS, which are no longer recommended and could bias SOS incidence and the derived results (S/VS SOS proportion, DF treatment duration).