There are several other genetic conditions that exhibit abnormal CCT measurements, including Marfan syndrome [15,16] and aniridia [17,18], thus implicating the defective genes, fibrillin-1 (FBN1) [19,20] and paired box 6 (PAX6) [21,22], respectively, as potential modifiers of CCT. This evidence concerns the gene PAX6 and aniridia.