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Proceedings Paper

A novel scanning method for large scan depth anterior segment OCT
Author(s): Rahul Yadav; Geunyoung Yoon
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Paper Abstract

A novel optical scanning method for an anterior segment optical coherence tomography (AS-OCT) system has been described. This method has been designed for imaging the entire anterior segment of the eye (from cornea to posterior surface of the crystalline lens) at a time. The ability to image the entire anterior segment is crucial in understanding the mechanism of human accommodation and the efficacy of accommodative intraocular lenses. In a conventional scanning system the beam is shined straight into the eye parallel to the optical axis. For anterior segment imaging, large lateral scan area leads to an increase in the angle of incidence on each of the four ocular surfaces. This causes significant reduction in signal reflected from regions further from the optical axis. This reduction combined with loss in signal due to coherence makes it difficult to image the entire anterior segment of the eye, where optical depth penetration of 10mm is required. To overcome this limitation, we have designed a new OCT scanning system, which achieves close to normal incidences across all the lateral locations on the ocular surfaces within a 6 mm clear aperture. This provides an increase in the amount of light scattered back to the system resulting in higher signal-to-noise ratio (SNR). The scanning system consists of two different custom designed lenses, one of them optimized for cornea and the anterior surface of the crystalline lens, while the other for the posterior surface of the crystalline lens. Two semicircular halves of each lens were glued together to form a single optical system. To evaluate the performance of our design we constructed and imaged a model eye and compared it with images obtained by conventional telecentric scanning method. SNR improvement by a factor of 3.71 was observed for the front surface of the lens and 18.83 for the back surface of the lens.

Paper Details

Date Published: 3 March 2010
PDF: 6 pages
Proc. SPIE 7550, Ophthalmic Technologies XX, 75500M (3 March 2010); doi: 10.1117/12.841945
Show Author Affiliations
Rahul Yadav, Institute of Optics, Univ. of Rochester (United States)
Flaum Eye Institute, Univ. of Rochester (United States)
Geunyoung Yoon, Institute of Optics, Univ. of Rochester (United States)
Flaum Eye Institute, Univ. of Rochester (United States)


Published in SPIE Proceedings Vol. 7550:
Ophthalmic Technologies XX
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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