GSTM1 and Schnyder corneal dystrophy: Conversely, factors that decrease this rate (e.g., higher plasma viscosity, as it occurs in extreme exercise40, infection and/or inflammation41, or decreased erythrocytes flexibility, as it occurs in an SCD ‘crisis’) will magnify the equilibrium character of Hb oxygenation, and thus will increase the contribution of both conformational states of Hb.