US Patent 7419264 Ophthalmic aberrometer for measuring aberrations in the eye

A ophthalmic aberrometer uses a wavefront sensor aligned with an eye under examination through an optical path and a light source for introducing a light beam into the eye via the optical path, wherein the optical path has a reference through which the light beam passes before passing to an eye retina to form a reference spot on the retina, a focus dynamic range extender, and an astigmatism dynamic range extender positioned in the optical path between the reference and an eye under examination. The wavefront sensor is positioned to receive a wavefront reflected from the eye retina via the optical path.