A computer program for the optimization and evaluation of optical systems, successfully used since 1978, is the object of the present article. Although it is quite simple when used for designing routine optical systems, the considerable amount of its flexibility makes it particularly suitable in handling complex optical systems. As a matter of fact, it can be applied in handling a variety of cases: cylindric and aspheric lenses, tilts, decentrations, afocal systems, multi-configuration mode systems. In order to accelerate convergence, a wide range of options concerning computing methods are provided. In fact, the choice of the mathematical method, of the way of computing the damping factor and of the way of handling boundary conditions is readily available. The use of solves, such as the optimization on best focus or on paraxial focus, reduces the number of variables, often accelerates convergence and, in some cases, prevents stagnation. The capability of reducing sensitivity to manufacturing errors, besides the automatic choice of glasses for any couple of wavelengths achromatization, makes it very effective in cost reduction. Moreover, weights on field, wavelength and aperture and many constraints among different elements and/or configurations can be assigned. System evaluation includes, among other features, diffraction and geometrical MTF and semiautomatic Statistical manufacturing tolerances. Moreover a wide variety of graphical outputs is provided: spot diagrams, MTF plots, layout plots, transverse ray aberrations, glass maps and manufacturing drawings. Results obtained with the present program are reported in the paper.