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Proceedings Paper

Fast optical measurement of intraocular straylight
Author(s): Harilaos Ginis; Onurcan Sahin; Pablo Artal
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Paper Abstract

Light scattering in the human eye can deteriorate image quality and limit visual performance especially at the presence of a glare source. Optical measurement of straylight in the human eye is a challenging task where issues related to various inherent artifacts must be addressed. We report on a novel instrument based on the principle of double-pass optical integration that has been adapted for fast measurements suitable for a clinical setting. The instrument utilizes a light source formed by an array of green light emitting diodes that is projected onto the ocular fundus. The source has two concentric parts, a disk (field angle 0-3 degrees) and an annulus (3 - 8 degrees) that are modulated at different frequencies. A silicon photomultiplier receives the light reflected from the central part of the fundus and the Fourier transform of the signal reveals the contribution of each part of the source. Their relative amplitude is used to quantify light scattering by means of the straylight parameter. The instrument was initially validated using known diffusers. Straylight in a cohort of cataract patients (N=39) was measured. The optically measured straylight parameter was correlated to the clinical cataract grade as well to the psychophysically estimated value. The measurement method, utilizing rotational symmetry and coding filed angles with different frequencies eliminates the need for a highperformance camera and allows fast measurements. This approach can be further advanced with multiple wavelengths and field angles to perform other measurements such as that of the macular pigment density.

Paper Details

Date Published: 20 March 2015
PDF: 4 pages
Proc. SPIE 9307, Ophthalmic Technologies XXV, 93070R (20 March 2015); doi: 10.1117/12.2077135
Show Author Affiliations
Harilaos Ginis, Univ. de Murcia (Spain)
Onurcan Sahin, Institute of Vision & Optics, Univ. of Crete (Greece)
Pablo Artal, Univ. de Murcia (Spain)

Published in SPIE Proceedings Vol. 9307:
Ophthalmic Technologies XXV
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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