In this paper, we present a design strategy for single layer metasurface lenses based on dielectric resonators. This strategy is based on a robust optimization procedure for the resonator distribution in order to meet required performances (e.g. encircled energy, bandwidth, field of view, etc.). Possible deviations due to manufacturing errors are taken into account in the design procedure. This is applied to the design of array of microlenses for maskless lithography applications. The final design shows more uniform focusing performances (bandwidth 20 nm at 395 nm - 415 nm, field of view ±60 mrad) and increased robustness against manufacturing errors, compared to designs based on analytic phase projections.