The numerical map has keratometric values observed along the corneal surface. The system calculates the average value of all points on the meridians of the 3mm optical zone, to identify the meridian with the greatest curvature. The flatest meridian is obtained at 90º from the most curved. The meridians are then described in terms of their dioptric power, radius of curvature and axis. The diopters are plotted numerically every 20º for the detected rings. The colors of the values accompany the colors of the relative scale.