Optical coherence tomography for eye-length measurement
AssigneeCarl Zeiss Meditec AG
InventorsYan Zhou, Keith O'Hara
Life of this patent
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Abstract
An accurate measure of eye length can be obtained using concurrent OCT measurements. A position OCT device can be used to continually monitor the position of the front surface of the cornea, while a distance OCT device can determine the apparent distance between the front surface of the cornea and the front surface of the retina. Since the eye is likely to move during the period of time between measurements of the cornea and retina, the monitored position of the cornea can be used to correct the apparent length measurement by the amount of eye movement over that period of time, in order to obtain an accurate measure of eye length. In some embodiments a single OCT device can serve the dual role of monitoring eye position while making eye length measurements
Claims21
A system for determining eye length, comprising:
- an interferometer operable to transmit light along a reference path and a sample path;
- an optical path altering element positioned along one of the reference path, or the sample path, the optical path altering element operable to alternately match a length of the reference arm to a first length of the sample path corresponding to a first surface of the eye and a second length of the sample path corresponding to a second surface of the eye, the optical path altering element accomplishing the alternate matching at a speed that prevents an unacceptable amount of movement of the eye during a measurement;
- and
- a processing device operable to receive a signal from the interferometer indicating a measured position of the first and second surfaces of the eye, and using this signal to determine eye length.
A method of determining the distance between the cornea and the retina of a patient's eye using an interferometer arranged to transmit light along sample and reference paths, said method comprising the steps of:
- selectively altering the length of one of the reference or sample paths to alternately match a length of the reference arm to a first length of the sample path terminating at the cornea and a second length of the sample path terminating at the retina, the path length altering step being performed at a speed that prevents an unacceptable amount of movement of the eye during a measurement;
- processing signals from the interferometer indicating a measured position of the cornea and retina and using this signal to determine eye length;
- and
- displaying the results of the eye length determination.
Dependencies are inferred from the claim text.