Knowing that PON1 has a crucial role in lipid metabolism and has antioxidant and anti-inflammatory properties, we aimed to investigate the influence of PON1c.192Q > R and PON1c.55L > M polymorphisms on PON1 activity and laboratory parameters and the association between PON1 activity and clinical manifestations in SCD patients. This evidence concerns the gene PON1 and Schnyder corneal dystrophy.