Large diopter range real time sequential wavefront sensor
Example embodiments of a large dynamic range sequential wavefront sensor for vision correction or assessment procedures are disclosed. An example embodiment optically relays a wavefront from an eye pupil or corneal plane to a wavefront sampling plane in such a manner that somewhere in the relaying process, the wavefront beam from the eye within a large eye diopter range is made to reside within a desired physical dimension over a certain axial distance range in a wavefront image space and/or a Fourier transform space. As a result, a wavefront beam shifting device can be disposed there to fully intercept and hence shift the whole beam to transversely shift the relayed wavefront.
1. An ophthalmic measurement device comprising:
a light source configured to emit a beam of light;
a reference optical path;
a detector configured to output an intensity signal indicating the intensity of a beam of light received at the detector;
at least one optical coupling device configured to receive the beam of light, couple a first portion of the beam of light to the reference optical path, direct a second portion of the beam of light as an illumination beam to the eye of a patient, couple a returned beam from the eye of the patient with a reference beam from the reference optical path to form a low coherence interference beam and direct the low coherence beam to the detector;
a scanning element, positioned to intercept the illumination beam, configured to direct/scan the illumination beam to/on the eye of the patient;
a large diopter range real time wavefront sensor with the large diopter range real time wavefront sensor initially calibrated for predetermined distances to selected anatomical features and configured to output wavefront measurements of the eye of the patient;
a controller, coupled to the light source, to the scanning element, to the large diopter range real time wavefront sensor, and to the detector, with the controller configured to control the scanning element to cause reflection(s) of the illumination beam from one or more selected anatomical feature(s) of the eye of a patient to form the returned beam returned to the optical coupling device, to process the intensity signal output by the detector when the low coherence interference beam is used to determine the distance to the selected anatomical features using low coherence optical interferometry techniques and to compensate axial movement of the patient eye for the wavefront measurement.
2. The ophthalmic measurement device of claim 1 with the large diopter range real time wavefront sensor including a controllable transverse wavefront beam shifting element, with the controller coupled to the controllable transverse wavefront beam shifting element and configured to control the transverse beam shifting element to compensate transverse movement of the patient eye for the wavefront measurement.
3. The ophthalmic measurement device of claim 1 with the controller further configured to determine the central thickness of the cornea, the anterior chamber depth of the eye of the patient, the natural or implanted lens thickness and position in the eye and/or the eye length (from the apex of the cornea to the retina) as determined using low coherence optical interferometry techniques.
4. The ophthalmic measurement device of claim 3 with the controller further configured to combine measurements determined using low coherence optical interferometry measurements and wavefront measurements for detection of eye status including phakia, aphakia and pseudo-phakia.
5. The ophthalmic measurement device of claim 1 with the controller further configured to control the scanning element to perform optical coherence tomography measurements to generate corneal front and back surface profiles, the natural lens front and back surface profile and/or the position of the intraocular lens (IOL) that sits in the eye of a patient.
6. The ophthalmic measurement device of claim 1 with the controller further configured to combine measurements determined using low optical coherence tomography measurements and wavefront measurements to indicate the degree of optical scattering and/or opacity of an eye lens or optical media.
7. The ophthalmic measurement device of claim 1 with the controller further configured to control the scanning element to perform optical coherence tomography measurements to predict the actual position where the IOL will sit in the eye of the patient based on the optical coherence tomography measurements.
8. The ophthalmic measurement device of claim 1 with the controller further configured to determine the refraction of the cornea, the phakic eye and the aphakic eye based on low coherence optical interferometry distance determinations and optical coherence tomography measurements.
9. The ophthalmic measurement device of claim 1 where the detector includes a spectrometer and is configured to implement a spectral domain detection scheme.
10. The ophthalmic measurement device of claim 1 where the light source includes a wavelength swept source and is configured to implement a spectral domain detection scheme.