Abstract: Disclosed is a computer-implemented method for correcting refractive errors in a living eye using a laser vision correction system that involves first calculating an amount of sphere based on preoperative manifest refraction and higher order aberrations data associated with the eye, and then correcting for the calculated amount of sphere by ablating at least a portion of the eye. The preoperative manifest refraction may include preoperative manifest sphere, preoperative spherical equivalent, regular astigmatism, and oblique astigmatism, and the preoperative higher-order aberrations may include 4th-order spherical and 3rd root mean square. Other factors may also be used to adjust the calculated amount of sphere. A device readable medium for storing the calculation and instructions for operating a laser vision correction system for practicing the method is also disclosed, as is a method of treating refractive errors.