public EyeRX getEyeRX()
        {
            double       sph       = nudSph.getValue();
            double       cyl       = nudCyl.getValue();
            int          axis      = Convert.ToInt32(nudAxis.getValue());
            double       nearAdd   = nudNear.getValue();
            double       intAdd    = nudInt.getValue();
            double       prism     = nudPrism.getValue();
            ComboBoxItem cb        = (ComboBoxItem)txtBase.SelectedItem;
            String       prismBase = "";

            if (cb != null)
            {
                prismBase = cb.Content.ToString();
            }
            EyeRX eyeRX = new EyeRX(sph, cyl, axis, nearAdd, intAdd, prism, prismBase, this.VADistance, this.VANear);

            return(eyeRX);
        }
 //On continue, set managers prescription and navigates to next page
 public async void continue_Click(object sender, RoutedEventArgs e)
 {
     //Checks if null and is so displays dialog
     if (pRightEye.isNull() || pLeftEye.isNull())
     {
         //If user wants to skip prescription
         if (await validationDialog())
         {
             manager.setPatientPrescription(prescription);
             manager.navigateMain(typeof(FaceShapePage));
         }
     }
     else
     {
         EyeRX rightEye = pRightEye.getEyeRX();
         EyeRX leftEye  = pLeftEye.getEyeRX();
         prescription = new Prescription(rightEye, leftEye);
         manager.setPatientPrescription(prescription);
         manager.navigateMain(typeof(FaceShapePage));
     }
 }
 //Constructor
 public Prescription(EyeRX rightEye, EyeRX leftEye)
 {
     this.rightEye = rightEye;
     this.leftEye  = leftEye;
     evaluatePrescription();
 }