An optical film includes a layer of simultaneous biaxially stretched polyolefin film that is substantially non-absorbing and non-scattering for at least one polarization state of visible light. The layer has x, y, and z orthogonal indices of refraction where at least two of the orthogonal indices of refraction are not equal. The layer has an in-plane retardance of 100 nm or less and an out-of-plane retardance of 50 nm or greater.