Patent ID: 7296895

Claim:
In a method for measuring a wavefront aberration of an eye in which a first, reference, object beam projected parallel to a known reference axis is input to the eye at a first, reference location (P 1 ) on a cornea of the eye such that the first beam is scattered from a location ( 1 ) on the retinal surface and further imaged onto a detector at a reference position (x 1 , y 1 ), and at least a sequential, second object beam parallel to and displaced a known amount (d) from the reference beam is projected into the eye at a second location (P 2 ) on the cornea, is scattered from a location ( 2 ) on the retinal surface and further imaged onto the detector at a second position (x 2 , y 2 ), such that a displacement (Δx 2−1 , Δy 2−1 ) can be measured and from which wavefront aberration information can be calculated, the improvement characterized by: inputting a third beam corresponding to each sequential second beam at an angle (α) to the reference axis that enters the cornea at the same location as each second beam (P 2 ) and is scattered from a location ( 3 ) on the retinal surface substantially corresponding to location ( 1 ) and further imaged onto the detector at a third position (x 3 , y 3 ), such that a displacement (Δx 3−1 , Δy 3−1 ) can be measured and the wavefront aberration calculated corresponding to location P 2 on the cornea, whereby the wavefront aberration for cornea location P 2 from the third beam data is more accurate than the corresponding measurement from the second beam measurement.