Determination of the point-spread function of human eyes using a hybrid optical–digital method

Santamaría, Javier; Artal, Pablo; Bescós, J.

doi:10.1364/josaa.4.001109

Cited by 233 publications

(177 citation statements)

References 12 publications

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“…This speckle can cause masking that reduces contrast sensitivity." 1 We adopted two procedures to eliminate the effect of speckle on our MTF measurements. First, as shown in the inset of Fig.…”

Section: Methodsmentioning

confidence: 99%

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Double-pass and interferometric measures of the optical quality of the eye

et al. 1994

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We compare two methods for measuring the modulation transfer function (MTF) of the human eye: an interferometric method similar to that of Campbell and Green [J. Physiol. (London) 181,576 (1965)] and a double-pass procedure similar to that of Santamaria et al. [J. Opt. Soc. Am. A 4, 1109(1987]. We implemented various improvements in both techniques to reduce error in the estimates of the MTF. We used the same observers, refractive state, pupil size (3 mm), and wavelength (632.8 nm) for both methods. In the double-pass method we found close agreement between the plane of subjective best focus for the observer and the plane of objective best focus, suggesting that much of the reflected light is confined within individual cones throughout its double pass through the receptor layer. The double-pass method produced MTF's that were similar to but slightly lower than those of the interferometric method. This additional loss in modulation transfer is probably attributable to light reflected from the choroid, because green light, which reduces the contribution of the choroid to the fundus reflection, produces somewhat higher MTF's that are consistent with the interferometric results. When either method is used, the MTF's lie well below those obtained with the aberroscope method [Vision Res. 28, 659 (1988)]. On the basis of the interferometric method, we propose a new estimate of the monochromatic MTF of the eye.

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Section: Methodsmentioning

confidence: 99%

“…Am. A 4, 1109(1987]. We implemented various improvements in both techniques to reduce error in the estimates of the MTF.…”

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confidence: 99%

Double-pass and interferometric measures of the optical quality of the eye

et al. 1994

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“…As a matter of fact, the first experimental measurement of the optical MTF in vivo was achieved by using Equation 11, where the neural CSF was measured with gratings formed directly on the retina by means of interferometric methods, which bypass the optical system. [36][37] Modern measurements of the optical MTF are based on an objective procedure, does not relay on contrast-threshold measurements. As can be seen in figure 4, however, the results obtained with this technique do not differ in anything essential from those derived with an interferometric method.…”

Section: Figurementioning

confidence: 99%

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Dı́ez-Ajenjo

Capilla

2010

Journal of Optometry

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We review the psychophysics of the spatio-temporal contrast sensitivity in the cardinal directions of the colour space and their correlation with those neural characteristics of the visual system that limit the ability to perform contrast detection or pattern-resolution tasks. We focus our attention particularly on the influence of luminance level, spatial extent and spatial location of the stimuli -factors that determine the characteristics of the physiological mechanisms underlying detection. Optical factors do obviously play a role, but we will refer to them only briefly. Contrast sensitivity measurements are often used in clinical practice as a method to detect, at their early stages, a variety of pathologies affecting the visual system, but their usefulness is very limited due to several reasons. We suggest some considerations about stimuli characteristics that should be taken into account in order to improve the performance of this kind of measurement. RESUMENSe revisa la psicofísica sobre la sensibilidad al contraste con patrones espacio-temporales en las direcciones cardinales del espacio de color y su relación con las características neuronales del sistema visual que limitan la habilidad para realizar una tarea de detección de contraste o de resolución de patrones. La atención se centra especialmente en la influencia del nivel de luminancia, el tamaño y la localización espacial de los estímulos, en la medida que estos son los factores más importantes que determinan las características de los mecanismos fisiológicos que median la detección. Obviamente, los factores ópti-cos también juegan un papel en el conjunto del sistema visual, pero nos referiremos a ellos sólo brevemente. Las medidas de sensibilidad al contraste son a menudo usadas en clínica como método para detectar, en un estado temprano, una amplia variedad de patologías del sistema visual, pero su utilidad en la práctica es bastante limitada por diferentes razones. Sugerimos que ciertas consideraciones sobre los estímulos deberían ser tenidas en cuenta si se quiere mejorar las prestaciones actuales de este tipo de medidas. (J Optom 2010;3:2-19 ©2010 Consejo General de Colegios de Ópticos-Optometristas de España) PALABRAS CLAVE: sensibilidad al contraste; patrones espacio-temporales; espacio de color; direcciones cardinales; caminos visuales. INTRODUCTIONDuring the last three decades, the possibility of early detection of a variety of pathologies affecting the visual system by means of the measurement of spatial and temporal contrast sensitivity functions -CSFs-has been thoroughly explored. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] (Burr D, et al. IOVS 2003;44: ARVO E-Abstract 3193). It has been shown, however, that the usefulness of these functions is rather limited in practice, for several reasons. In the first place, measurements are often limited to the fovea, whilst anatomical damage and functional loss frequently begin outside this region [see, for example, F. Rowe's book 17 ]. In fact, different perimetry technique...

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“…The double-pass (DP) method is an objective technique based on recording images of a pointsource object after reflection on the retina and a double passage through the ocular media [1]. Unlike wave-front sensors, the DP technique provides combined information of both aberrations and small-angle intraocular scatter [2].…”

Section: Introductionmentioning

confidence: 99%

Impact of scatter on double-pass image quality and contrast sensitivity measured with a single instrument

Bueno¹,

Pérez²,

Benito³

et al. 2015

Biomed. Opt. Express

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Abstract:We compared objective Double-Pass (DP) image quality data with subjective visual parameters measured within the same modified instrument for different amounts of scatter. The original DP imaging channel of a clinical instrument was maintained intact and two additional channels were included, one for visual testing and another for tear film (TF) imaging by using a retro-illumination technique. Contrast sensitivity (CS) was compared with measurements of the Objective Scattering Index (OSI) obtained from DP retinal images corresponding to different scatter levels induced by pre-defined filters. OSI values were correlated with the change in CS for different spatial frequencies measured with the same instrument. Since TF and DP images were recorded at the same rate, this provided additional information about the dynamic spatial stability of the tear film. This new DP instrument has been proven to provide accuracy and repeatability, and to be suitable for clinical diagnosis, with a complete evaluation of the eye's performance by a simultaneous objective and subjective assessment under the same experimental conditions.

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Determination of the point-spread function of human eyes using a hybrid optical–digital method

Cited by 233 publications

References 12 publications

Double-pass and interferometric measures of the optical quality of the eye

Double-pass and interferometric measures of the optical quality of the eye

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Impact of scatter on double-pass image quality and contrast sensitivity measured with a single instrument

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