Focused ion beam (FIB) systems based on high brightness plasma ion sources are becoming largely diffuse in material and semiconductor research, thanks to the higher current densities and milling rates provided by noble gas ions (e.g., Xe) compared with traditional liquid metal Ga FIBs. In this paper, we demonstrate the feasibility of a rapid, direct milling of microlenses in glass substrates using high current Xe plasma FIB. We present quantitative analyses of roughness and profile of microlenses with diameters up to 230-µm and focal distances between 7 mm and 1.4 mm. We characterized the performance of the lenses by mapping the transmitted intensity through the lenses, by forming an image of a resolution object by scanning the focused spot and collecting the transmitted intensity, and in full-field imaging experiments. The results indicate the applicability of plasma focused ion beam systems for direct writing in glass of high-quality micro-optical elements with diffraction-limited focusing.