Publications by authors named "Rajat Agarwala"

2 Publications

  • Page 1 of 1

Utilizing minicomputer technology for low-cost photorefraction: a feasibility study.

Biomed Opt Express 2020 Nov 7;11(11):6108-6121. Epub 2020 Oct 7.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, Tuebingen, 72076, Germany.

Eccentric photorefraction is an objective technique to determine the refractive errors of the eye. To address the rise in prevalence of visual impairment, especially in rural areas, a minicomputer-based low-cost infrared photorefractor was developed using off-the-shelf hardware components. Clinical validation revealed that the developed infrared photorefractor demonstrated a linear working range between +4.0 D and -6.0 D at 50 cm. Further, measurement of astigmatism from human eye showed absolute error for cylinder of 0.3 D and high correlation for axis assessment. To conclude, feasibility was shown for a low-cost, portable and low-power driven stand-alone device to objectively determine refractive errors, showing potential for screening applications. The developed photorefractor creates a new avenue for telemedicine for ophthalmic measurements.
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http://dx.doi.org/10.1364/BOE.400720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7687974PMC
November 2020

Direct modeling of foveal pit morphology from distortion-corrected OCT images.

Biomed Opt Express 2019 Sep 26;10(9):4815-4824. Epub 2019 Aug 26.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, Tuebingen, 72076, Germany.

Inherent distortions affect the spatial geometry of optical coherence tomography (OCT) images and consequently the foveal pit dimensions. Distortion correction provides an accurate anatomical representation of the retinal shape. A novel approach that automatically extracts foveal pit metrics from distortion-corrected OCT images using a sum of Gaussian function is presented. Foveal width, depth and slope were determined in 292 eyes with low fitting errors and high repeatability. Comparisons to undistorted scans revealed significant differences. To conclude, the internal OCT distortions affect the measurements of the foveal pit with their correction providing further insights into the role of foveal morphology in retinal pathologies and refractive development.
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http://dx.doi.org/10.1364/BOE.10.004815DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6757460PMC
September 2019