Glasses containing silicon dioxide (SiO2) and/or boron oxide (B2O3) as glass formers and having a refractive index nd of greater than or equal to 1.9, as measured at 587.56 nm, and a density of less than or equal to 5.5 g/cm3, as measured at 25° C., are provided. Optionally, the glasses may be characterized by a high transmittance in the visible and near-ultraviolet (near-UV) range of the electromagnetic spectrum and/or good glass forming ability.