A new paper published in the July 1 issue of OSA’s Optics Letters shows that researchers in Australia have created a new one-step test that uses holograms to diagnose the astigmatic error of the human eye, a key measurement in determining the appropriate prescriptions for eye glasses in patients. This new technique adds to an earlier one, developed by the same researchers, for using a single hologram to measure another important property, the spherical refractive error of the eye.