Parametric representation of Stiles–Crawford functions: normal variation of peak location and directionality

Applegate, Raymond A.; Lakshminarayanan, Vasudevan

doi:10.1364/josaa.10.001611

Cited by 180 publications

(125 citation statements)

References 50 publications

(28 reference statements)

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“…The Stiles-Crawford effect is difficult to account for accurately when the area of the retina stimulated is not restricted to the fovea [36] and when the entry pupil location for peak maximum sensitivity is not known [37].…”

Section: Resultsmentioning

confidence: 99%

Changes in color vision with decreasing light level: separating the effects of normal aging from disease

Barbur¹,

Konstantakopoulou²

2012

J. Opt. Soc. Am. A

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. The purpose of this study was to obtain additional information about the health of the retina (HR) by measuring the rate of loss of chromatic sensitivity with decreasing light level. The HR index is introduced to separate the effects of normal aging from early stage disease. For normal subjects the HR index is largely independent of age (r 2 ∼ 0.1), but ∼11% of clinically normal, asymptomatic, older subjects exhibit values below the 2σ limit. The HR index provides a single number that captures how light level affects chromatic sensitivity irrespective of age and can be used to screen for preclinical signs of retinal disease. Permanent

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Section: Resultsmentioning

confidence: 99%

Changes in color vision with decreasing light level: separating the effects of normal aging from disease

Barbur¹,

Konstantakopoulou²

2012

J. Opt. Soc. Am. A

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“…(Ref. 13). The differences between reflectometric and psychophysical are still more marked at higher eccentricities.…”

Section: Introductionmentioning

confidence: 99%

Model for cone directionality reflectometric measurements based on scattering

Marcos

Burns

1998

J. Opt. Soc. Am. A

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Reflectrometric measurements provide an objective assessment of the directionality of the photoreceptors in the human retina. Measurements are obtained by imaging the distribution at the pupil plane of light reflected off the human fundus in a bleached condition. We propose that scattering as well as waveguides must be included in a model of the intensity distribution at the pupil plane. For scattering, the cone-photoreceptor array is treated as a random rough surface, characterized by the correlation length T (related to the distance between scatterers, i.e., mean cone spacing) and the roughness standard deviation (assuming random length variations of the cone outer-segment lengths that produce random phase differences). For realistic values of T and we can use the Kirchhoff approximation for computing the scattering distribution. The scattered component of the distribution can be fitted to a Gaussian function whose width depends only on T and . Actual measurements vary with experimental conditions (exposure time, retinal eccentricity, and ) in a manner consistent with the scattering model. However, photoreceptor directionality must be included in the model to explain the actual location of the peak of the intensity distribution in the pupil plane and the total angular spread of light.

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“…Unfortunately, due to the limitations of our modeling software we were not able to include such effects. As the aberrations incorporated into the present model appear to be less than those considered problematic by Vohnsen and, moreover, all previous experiments had been conducted using SCE neutralizing filters mounted in the pupil plane of the eye, 22,[27][28][29][30]33 we considered this approach to be reasonable. Nonetheless, readers should be aware, that the impact of the SCE on DoF in the presence of higher magnitudes of spherical aberration may differ slightly from those indicated here.…”

Section: Discussionmentioning

confidence: 99%

“…This was incorporated into the model by modifying the transmission function: instead of being a uniformly lit pupil it was set to be a Gaussian apodized pupil with a SCE factor 22 of 0.12 mm -2 (this value is an estimate derived from psychophysically conducted measurements).…”

Section: Modeling Stiles-crawford Effect (Sce)mentioning

confidence: 99%

Depth-of-Focus and its Association with the Spherical Aberration Sign. A Ray-Tracing Analysis

Bakaraju

Ehrmann

Papas

et al. 2010

Journal of Optometry

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PURPOSE: To investigate the relationship between the sign of spherical aberration (SA) and the corresponding depth-of-focus (DoF) values around best focus, at three different spatial frequencies (SF). Additionally, to study the influence of the Stiles-Crawford effect (SCE) on DoF. METHODS: We modeled schematic eyes having a range of SA values, C (4, 0), from -0.20 to 0.20 μm, at 6 mm pupil, in a ray-tracing software (Zemax). The through-focus optical performance was obtained via Modulation Transfer Function (MTF) calculations using thin paraxial lenses in-front of the model eye, from -2.00 to+2.00 D in 0.05D steps. Through-focus full-width (defocus) occurring at the half maximum of MTF value was considered as DoF, in diopters. RESULTS: For the low-SF configuration, +SA and -SA results were close to being mirror symmetries of one another. However, for midand high-SF targets, in the SA range spanning from -0.15 to 0.15 μm, models of equal SA magnitude but opposite sign produced similar DoF measures, but those with SA more negative than -0.15 μm showed marginally higher DoF than their positive counterparts. The SCE improved DoF for low SF (10 cycles/mm), while for mid and higher SF (>30 cycles/mm) mixed results were observed. CONCLUSIONS: As regards presbyopic-correction strategies that use deliberately induced aberrations to increase the depth of focus, the current study suggests that both positive and negative SA have equal potential. However, practical considerations will probably limit the useful DoF achievable through the utilization of SCE in presbyopes. for reference to a contemporary record detailing refractive history. RESUMEN OBJETIVO:Investigar, para tres frecuencias espaciales (FE) distintas, la relación entre el signo de la aberración esférica (AE) y la correspondiente profundidad de foco (PdF) alrededor del mejor foco. Además, se estudiará cómo afecta el efecto Stiles-Crawford (ESC) a la PdF. MÉTODOS: Hemos utilizado un modelo de ojo esquemático con distintos valores de aberración esférica (AE) (C (4, 0) comprendido entre 0.20 y 0.20 μm, para un diámetro de pupila de 6 mm) para investigar la relación que existe entre el signo de la AE y la correspondiente profundidad de foco (PdF) alrededor del mejor foco para tres frecuencias espaciales (FE) distintas. También se estudió la influencia del efecto Stiles-Crawford (ESC). RESULTADOS: Para FE bajas, los resultados correspondientes a +AE y AE presentan simetría especular. Sin embargo, para FE medias y altas, y en el intervalo de AE comprendido entre 0.15 y 0.15 μm, modelos de igual AE (en módulo) pero distinto signo da lugar a valores de PdF similares, pero para valores de AE más negativos que 0.15 μm se obtuvieron PdF ligeramente más altas que para un valor positivo equivalente de AE. El ESC hace que aumente la PdF para FE bajas (10 ciclos/mm), mientras que para FE medias y altas (>30 ciclos/mm) se observan resultados variados. CONCLUSIONES: En lo que respecta a las estrategias de corrección de la presbicia basadas en la inducción deliberada de ...

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Parametric representation of Stiles–Crawford functions: normal variation of peak location and directionality

Cited by 180 publications

References 50 publications

Changes in color vision with decreasing light level: separating the effects of normal aging from disease

Changes in color vision with decreasing light level: separating the effects of normal aging from disease

Model for cone directionality reflectometric measurements based on scattering

Depth-of-Focus and its Association with the Spherical Aberration Sign. A Ray-Tracing Analysis

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