Abstract: Optimizing visual performance of a spectacle lens using metrics of visual performance includes selecting one or more metrics of visual performance for the lens. Creating functions of the metrics of visual performance, each having a function value that decreases as a values of the metrics of visual performance increase. Creating a merit function for lens optimization, the merit function having a main term that contains a weighted sum of functions that decrease as the metrics of visual performance increase, the weighted sum of functions including a set of viewing directions or a set of points with a one-to one correspondence with the set of viewing directions. Minimizing the merit function to optimize lens surfaces. Then designing an optimal lens having the optimized lens surfaces to optimize visual performance.