Optical Scattering from Vitreous Floaters

Harmer, S. W., Luff, A. J. and Gini, G. (2021) Optical Scattering from Vitreous Floaters. Bioelectromagnetics, 43 (2). pp. 90-105. ISSN 1521-186X

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Abstract

Vitreous “floaters” are a common entoptic phenomenon that can result in significant reduction in quality of life in a proportion of sufferers. The authors use a computational mathematical model based on Fourier optics and reflection and transmission coefficients calculated for a planar type II collagen opacity suspended in aqueous to show that floaters are perceived by the patient through interference effects that result in significant variations in intensity on the retina when viewing a constant brightness surface. The model also predicts that backscattered intensity from floaters is ten thousand to one million times lower than the variations in intensity produced on the retina, which demonstrates that the visible effects of floaters for the patient can be highly significant, whereas clinical observation of the vitreous may be entirely unremarkable. Importantly, the results also demonstrate that floaters do not need to be opaque to cause symptoms, with only small differences in refractive index between the floater material and the surrounding vitreous needed to produce significant optical effects. The model predicts that pupil size is an important factor in determining the severity of symptoms from floaters, with constricted pupils giving much greater effect than dilated pupils. Finally, the authors’ model predicts that floaters degrade contrast sensitivity function, with greatest degradation occurring in the 5–40 cycles per degree spatial frequency range and that the effects of shadowing caused by floaters are very strongly correlated to the predicted degradation of contrast sensitivity function.© 2021 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.

Item Type: Article
Additional Information: ** Article version: VoR ** From Wiley via Jisc Publications Router ** History: received 02-06-2021; rev-recd 07-12-2021; accepted 18-12-2021; pub-electronic 30-12-2021. ** Licence for VoR version of this article: http://creativecommons.org/licenses/by-nc-nd/4.0/ © 2021 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Uncontrolled Keywords: floaters, vision, scattering, symptomatic vitreous opacity, contrast sensitivity function. Radiology, Nuclear Medicine and imaging, Physiology, General Medicine, Biophysics
Subjects: Q Science > QM Human anatomy
R Medicine > RE Ophthalmology
Divisions: Academic Areas > Department of Engineering, Computing and Design > Electrical Engineering
SWORD Depositor: Publications Router Jisc
Depositing User: Publications Router Jisc
Date Deposited: 21 Jan 2022 14:50
Last Modified: 04 Mar 2022 10:58
URI: https://eprints.chi.ac.uk/id/eprint/6105

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