The Toric Calculator Tool will calculate what toric contact lens is required to correct a specific astigmatic prescription. Using industry standard calculations, the application calculates 1; what initial trial lens should be used/ordered with a given spectacle prescription. 2; If the lens, when fitted to the patient, rotates off axis, the tool will calculate the new axis direction for lens trial/order. The tool also has a Back Vertex Distance calculator . This tool supplies both the calculated theoretical power for use with any manufacturer's lenses and specific parameters for the Bausch & Lomb toric lens portfolio. It is designed to provide a starting point for the toric lens selection and modification. The final prescription should be determined by the Eye Care Practitioner ' s normal toric lens fitting practices.