It should just be:
$ConditionalQuery->bindColumn("PracticeName", "s", "".(WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Practice_name')) ."", "WA_DEFAULT");
$ConditionalQuery->bindColumn("EyeTestConfirmation", "s", "".(WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','Eye_test_confirmation')) ."", "WA_DEFAULT");
But really I would think your version would have worked. Maybe contact me via skype and I'll take a few minutes to debug it with you this afternoon.