The Paragon CRT® Lens Calculator is a free, multifunctional prescription calculator designed to allow eye care professionals to quickly and accurately calculate the optimal CRT lenses for their patients. Prescription Calculator Reduce chair time and make the fitting process for CRT patients simpler and more efficient. Quickly calculate and evaluate myopic prescriptions on the fly or from your office. Choose between 6mm or 5mm Optic Zone Diameter. Additional Benefits Additional benefits of the Paragon CRT® Calculator include the ability to share results of the calculated prescriptions and to contact CooperVision SEC with any questions or concerns you have with the education link inside the calculator. The Paragon CRT® Lens Calculator is an educational lens fitting tool intended for professional eye care provider use. Only licensed eye care providers may place Paragon CRT lens orders. Eye care professionals may choose to use the app as part of their patient evaluation. The Paragon CRT® Lens Calculator is not intended as and does not constitute medical or optometric advice and eye care professionals should rely on their own expertise.