Diffusion of the retinal layers of the living human eye

Gorrand, Jean-Marie; Alfieri, R; Boire, Jean-Yves

doi:10.1016/0042-6989(84)90088-9

Cited by 24 publications

(11 citation statements)

References 15 publications

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“…This differs from the case of conventional double-pass measurements, where differences in polarization produced variations in the point-spread and modulation transfer functions. 26,45,46 Recent data obtained with the spatially resolved refractometer also show that ocular aberrations do not depend on the state of polarization. 25 This is a psychophysical technique, and the subjects did not perceive differences as a linear polarizer in the test channel was moved, for any of the pupil locations under test.…”

Section: Discussionmentioning

confidence: 99%

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

et al. 2002

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Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H). The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.

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Section: Discussionmentioning

confidence: 99%

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

et al. 2002

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“…The most important was treating the fundus posterior to the MP as a uniform reflecting surface. For short and middle wavelengths below 580 nm, reflections occur mostly at the RPE and at BM 35,36 and, therefore, melanin density at the RPE affects the amount of reflected light. RPE melanin is not constant throughout the fundus but exhibits a higher density at the fovea and, therefore, it has some effect in MPOD from reflectometry measurements.…”

Section: Discussionmentioning

confidence: 99%

Effect of intraocular scattering in macular pigment optical density measurements

et al. 2018

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Abstract. Fundus reflectometry is a common in-vivo, noninvasive method to estimate the macular pigment optical density (MPOD). The measured density, however, can be affected by the individual's intraocular scattering. Scattering causes a reduction in the contrast of the fundus image, which in turn leads to an underestimation of the measured density. Intraocular scattering was measured optically in a group of seven young, healthy subjects using the method of optical integration and was subsequently used to correctly estimate the MPOD from fundus images. It was shown that when scattering is not considered, the measured optical density using fundus reflectometry can be underestimated by as high as 16% for our group of subjects. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…The first passage through the eye does not lower the modulation of the fringes (because of the Maxwellian view); the second passage lowers the modulation depth by a known factor (0.65). Gorrand et al (1984) pointed out a third condition necessary for separating optical and retinal effects: tuning between the interference fringes projected onto the retina and the retinal image of the analysing grating. The modulation measurements were the same with 10 and 20 fringes, which indicates a satisfactory tuning (in the expfrimental conditions defined in the paragraph Results).…”

Section: Number Of Fringesmentioning

confidence: 99%

Separation of the Reflection by the Inner Limiting Membrane

Gorrand¹

1986

Ophthalmic Physiologic Optic

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A ray incident upon the inner limiting membrane is specularly reflected, whereas the other retinal structures reflect light diffusely into large solid angles. Thus by moving a small diaphragm inside the exit pupil, it is possible to separate the component of the reflected light which originates at the inner limiting membrane. To check that this light added to the aerial image is not caused by the specular reflection from an anterior surface (cornea or lens), interference fringes were projected onto the retina, and their modulation depth was measured in the plane conjugate with the retina: since the inner limiting membrane and the anterior media were the sources of modulated and unmodulated aerial images respectively, their contributions could be separately measured.

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Diffusion of the retinal layers of the living human eye

Cited by 24 publications

References 15 publications

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

Ocular aberrations with ray tracing and Shack–Hartmann wave-front sensors: Does polarization play a role?

Effect of intraocular scattering in macular pigment optical density measurements

Separation of the Reflection by the Inner Limiting Membrane

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