Method of establishing a unique machine independent reference frame for the eye

Abstract

The invention relates to a method and apparatus for uniquely and unambiguously aligning a patient's visual line of sight (LOS) to the optical axis of an ophthalmic instrument such as may be used for laser surgery or diagnostics. By the method of the invention, two alignment targets are imaged at different distances along the optical axis of the ophthalmic instrument. Viewing along the optical axis, a patient moves his or her eye until the two imaged targets are in alignment. When the two imaged targets are viewed in alignment by the patient, the patient's LOS is precisely aligned with the optical axis of the apparatus. By relying on the patient's ability to self-align, this technique ensures that measurements are taken within a reproducible reference frame that is unique to each patient but independent of the type of machine used. The invention is applicable to many instruments and procedures which require precise tracking and positioning of the eye, especially ocular laser surgery devices and various diagnostic instruments employed in tissue imaging or surface topography measurements.

Dependencies are inferred from the claim text.