title: Local photoreceptor alignment measured with a scanning laser ophthalmoscope.
abstract: The aim of this study was to develop a fast test for local photoreceptor alignment. Photoreceptor alignment is an important indicator of retinal integrity. Digitized images of fundus reflectance were obtained for 20-30 pupil entry positions with a custom built scanning laser ophthalmoscope (SLO). The data permitted the calculation of curve peakedness of the optical Stiles-Crawford effect (SCE) as a function of retinal location. We found that the peakedness is low in the central 0.5 deg, reaches a maximum at an eccentricity of 1-2 deg and gradually drops with increasing eccentricity. These data are in conformity with the anatomy of foveal cones. Additionally, the psychophysical SCE was measured with red light and an 8 deg stimulus. The mean peak position of the SCE in the pupil plane for both methods was similar, but the optical SCE was clearly steeper. The SLO provides a fast, reliable and objective way to determine local receptor alignment in the central retina.
authors.affiliation: Helmholtz Institute, Department of Ophthalmology, Utrecht University, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Delint
authors.forename: T T
authors.initials: TT
authors.lastname: Berendschot
authors.forename: D
authors.initials: D
authors.lastname: van Norren
mesh_terms: D000293:Adolescent; D000328:Adult; D005654:Fundus Oculi; D006801:Humans; D008875:Middle Aged; D019721:Ophthalmoscopes; D009887:Ophthalmoscopy / Q000379:methods*; D010786:Photoreceptor Cells / Q000502:physiology*