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Helge Martin Sudkamp, Peter Koch, Dierck Hillmann, Michael Münst, Malte vom Endt, claus von der Burchard, Johann Roider, Reginald Birngruber, Gereon Hüttmann; Towards a handheld and low-cost full-field OCT system for aberration corrected imaging. Invest. Ophthalmol. Vis. Sci. 2019;60(11):015.
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© ARVO (1962-2015); The Authors (2016-present)
Reliably imaging the retinal cone mosaic requires the correction of aberrations caused by imperfections of the eye. This correction is possible by adaptive optics, which is technically challenging and requires complex and expensive devices. Recent progress on numerical approaches for correcting aberrations promises to aberration correction without adaptive optics. These algorithms, however, require the phase information of the OCT-signal not to be disturbed by motion of the sample and, thus, high acquisition rates, which cannot be retrieved with current commercially available OCT systems.Here, we use a compact and potentially low cost full-field OCT approach, for numerically aberration corrected imaging.
We imaged the human retina using off-axis full-field time-domain (OA-FF-TD) OCT. The system used consists of only a few relatively inexpensive optical components and allows to build a handheld OCT device capable of imaging the human retina in vivo.Images were recorded from healthy volunteers. An iterative computational algorithm was applied to the data to determine and correct for low order aberrations like defocus and astigmatism as well as higher order aberrations.
We acquired volumetric images at a field of view of 1.6 mm x 0.7 mm x 1.4 mm from various retinal regions of healthy subjects. We were able to correct a defocus of -5 dpt numerically, which renders ametropia correction unnecessary (Fig. 1). We also corrected higher order aberrations and were able to resolve the cone mosaic above an eccentricity of 3° temporal to the fovea (Fig. 2).
OA-FF-TD-OCT is a promising new technology, for a simple and robust retina scanner system. In contrast to commercially available OCT systems, it allows for aberration free imaging of the human retina at large pupil sizes and thus is able to resolve single cells of the cone mosaic. Our technology allows to build compact devices, which could be used for home care.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.
Area close to the optic nerve head before (left) and after numerical ametropia correction. The field of view is 1,6 mm x 1,4 mm
Cone mosaic 8° temporal of to the fovea. The field of view is 5° x 2°
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