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Optical coherence aberrometry via in-vivo point spread function scanning

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First Author: S.Georgiev AUSTRIA

Co Author(s):    S. Georgiev   A. Kumar   L. Ginner   O. Findl   W. Drexler   R. Leitgeb     

Abstract Details

Purpose:

To demonstrate the feasibility of novel hardwareless digital interferometric aberrometry based on swept-source optical coherence tomography (SS-OCT).

Setting:

Center for Medical Physics and Biomedical Engineering, Medical University of Vienna

Methods:

With a swept source optical coherence tomography fiber-optics based setup, a narrow coherent beam at 1060 nm wavelength is used as a guide star onto the human fovea. The backscattered foveal point spread function (PSF) from the retinal nerve fiber layer (RNFL) or photoreceptor layer (PRL) is scanned, by using a large aperture in the detection channel to acquire all aberrations from ocular media. Postprocessing algorithms used in digital adaptive optics (DAO) are used to unwrap the phase error of the human eye, in order to characterize ophthalmic aberrations in accordance to ANSI norms.

Results:

Using a phantom model eye, en-face PSFs at scaled increments of experimentally induced second-order aberrations are comparatively evaluated with conventional wavefront reconstruction via Shack-Hartmann wavefront sensing (SH-WFS). Ophthalmic optical coherence aberrometry (OCA) is subsequently demonstrated in-vivo. Coefficients of repeatability and derived metrics such as refractive sphere (Sph), spherical equivalent (SE), scaled cylinder values expressed in power vector components, total root mean square wavefront error (RMS WFE), RMS WFE of lower (LOA) and higher-order aberrations (HOA) up to the 6th order, Strehl-ratio, as well as the modulation transfer function (MTF), showcase equivalency between OCA and conventional SH-WFS, but with the advantage of coherent depth control and the high sensitivity of swept source OCA.

Conclusions:

This first validation of swept source based aberrometry showcases how, without the need for additional hardware, objective assessment of human vision can be simultaneously implemented with the already well-established use of optical biometry and diagnostic imaging.

Financial Disclosure:

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