Some studies aimed to evaluate CAT in either AH or serum, or both, reported no significant differences in this enzyme (either levels or activity) between glaucoma and control subjects (Ferreira et al., 2004; Ghanem et al., 2010; Goyal et al., 2014), while others demonstrated an impairment in CAT in glaucoma (Majsterek et al., 2011). The gene discussed is CAT; the disease is glaucoma.