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Salihah Qaysi, Denise Valente, Brian Vohnsen; Analysis of photoreceptor pointing using quadrant pupil detection. Journal of Vision 2017;17(7):33. doi: 10.1167/17.7.33.
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© ARVO (1962-2015); The Authors (2016-present)
Photoreceptors are endowed with directional properties that are expressed by their angular sensitivity to incident light as well as directionality in retinal images commonly referred to as the Stiles-Crawford effect of the first kind and the optical Stiles-Crawford effect, respectively. Individual photoreceptor tilt can be analyzed by moving the incident light across the pupil when capturing retinal images [1, 2]. The aim of this study is to examine the viability of a quadrant pupil detection scheme in which light enters near the SCE peak and backscattered light is captured through four equal-sized sectors in the pupil from which individual photoreceptor tilt can be derived.
The method employs a pyramidal prism to capture simultaneously 4 high-resolution retinal images. A numerical analysis using Matlab is performed to quantify the angular tuning in scattered light from each cone in the captured retinal images. The experimental results for parafoveal retinal imaging in healthy subjects are compared with modeled cone mosaic images. Retinal photoreceptors are modeled by single-layered scattering by mitochondria in the ellipsoid . Retinal images are calculated through four equal-sized sectors in the pupil lane in a 4f system. The Modeled photoreceptors are placed in the retinal plane with different angular tilts.
The initial result of our sectored quadrant pupil imaging system allows not only determination of total intensity images, but also direct determination of photoreceptor inclinations in the backscattered light intensity. It is found that the method is highly suited to determine photoreceptor inclinations without requiring displacement of the incident light in the pupil plane, whereby the determination of photoreceptor tilt becomes simplified. The experimental results compared well with the theoretical expectations thereby confirming the potential of the technique. It offers the possibility to analysis cone photoreceptor tilt in 2-D and is expected to probe valuable when analyzing retinal disease.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting
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