PSMD1 and keratoconus: The effectiveness of the positive control and KC in preventing the molecular binding between the spike S1 RBD and ACE2 receptor was assessed by chemiluminescence using the horseradish peroxidase (HRP) substrate reaction on a spike S1 RBD-coated plate that had been pre-mixed with Fc-tagged ACE2 receptor and positive control anti-spike S1 RBD antibody or KC.