Colombo Elisa

Colombo Elisa
National University of Tucuman, National Conceil of Science and Technology, Argentina · Institute of light, environment and vision

PhD

About

84
Publications
15,476
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766
Citations
Citations since 2016
19 Research Items
254 Citations
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
Additional affiliations
- April 2016
National University of Tucuman
Position
  • Professor (Full)

Publications

Publications (84)
Article
Research on the correlation between the initial pupillary light reflex, the perceptual brightness, and the excitations of the photoreceptors was performed for unrelated self‐luminous 10° stimuli at low photopic light levels (5 to 80 cd/m²). All stimuli were optically characterized using a spectroradiometer. For determining the pupillary diameter, a...
Article
The ability of the human visual system to detect stimuli at low illumination levels provides awareness of potential risks. The influence of age and spectral power distribution on mesopic spectral sensitivity is analyzed. Two typical light sources are used, a high-pressure sodium lamp (HPS), with a higher content of long wavelengths, and a metal hal...
Article
In the field of Biological Sciences, the determination of the color of the specimens is of fundamental importance to answer a wide variety of questions. For a long time, the visual determination of color was the rule. Subsequently, several reference color charts, such as those of the Munsell Color System, have been developed and used. As a first ap...
Article
Full-text available
Amblyopia, a developmental disorder that resulted from physiological alterations on the visual cortex and the vision impairment early in life, is a consequence of an abnormal binocular experience during the critical period of visual system development called “neural plasticity period”. Such impairment causes not only a diminished visual acuity, but...
Article
Full-text available
The visual response in mesopic adaptation depends strongly not only on the level of luminance but also on the relative weight of the response of the cones and rods system. This highlights the importance of knowing the spectral power distribution (SPD) of radiation, when evaluating the functional vision. For this reason, this work proposes the measu...
Article
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Objective: Determination of color and evaluating its variation form the basis for a broad range of research questions. For studies on taxonomy, systematics, etc., resorting to mammal specimens in museum collections has a number of advantages over using field specimens. However, if museum specimens are to be for studying color, they should accuratel...
Article
La importancia de la inversión de recursos en educación, y más específicamente en lo referido a la formación científica y tecnológica, viene siendo destacada hace más de veinte años como estratégica para el crecimiento de un país. Se observa en los jóvenes una valoración positiva de la ciencia pero simultáneamente un sentimiento de incapacidad haci...
Article
Based on the experimental visual data obtained for self-luminous stimuli surrounded by a dark background, a new colour appearance model (CAM) for unrelated self-luminous stimuli, CAM15u, was previously developed. To extend the model to related self-luminous stimuli, the colour appearance of coloured self-luminous stimuli surrounded by a luminous ba...
Article
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Intra-specific color variation is often underestimated by researchers, and among mammals, intra-specific differences in coloration are poorly documented for most species. The main goal of this study was to apply an objective color measurement methodology to the study of a specific problem: the detection, if any, of patterns of changes in the fur co...
Article
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The purpose of this study is to determine the pupillary dynamics with periodical flashes from a peripheral glare source, in similar conditions to night driving, while focusing on dependence with age. We measured two groups of people: youth and adults. Maximum pupil size decreases due to periodic flashes. Latency does not present significant differe...
Article
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The role of color in taxonomic and systematic studies of several taxa is central. Color data are more valuable if they permit comparisons. We aimed to provide pelage objective color measurements of a series of Akodon budini and to use those color data to test and to quantitatively analyze the influence of both the lighting source and the measuring...
Article
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We analyzed different contrast metrics to scale the stimulus strength for suprathreshold reaction times (RTs) when it is modulated along an achromatic channel (L + M) and both chromatic channels L/M and S/(L + M) considering increments and decrements along these axes. RTs were examined as a function of the Weber luminance contrast; spatial luminanc...
Article
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The Contrast Sensitivity Function (CSF) is a valuable tool which can be used to characterize functional vision and also for the diagnosis and management of patients with different eye diseases. In spite of its usefulness, the CSF is currently hardly ever used in clinical practice. The aim of this study was to validate the use of the system called F...
Article
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Purpose: To measure log(s) and OSI parameters, both related to forward light scattering in the eye, in subjects with different kinds of early cataracts-nuclear or posterior subcapsular-and corrected visual acuity (CVA). Methods: 34 eyes of 19 patients ranged between 50 and 75 years old with diagnosed nuclear (14 eyes) or posterior subcapsular ca...
Article
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In sunny climates, Transition Spaces may place excessive demands on the human eye and become real functional vision barriers, since building morphology is influenced by the dynamics of daylight. In this study, we describe the lighting characterization of a case study located in the city of Mendoza, analysing different lighting magnitudes and their...
Article
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We determined the visual efficiency and visual discomfort for users of a typical transitional space in luminous climates. The subject moves from a brighter exterior to a dimmer interior, facing an abrupt change in the level of lighting as a potential functional vision barrier, mainly for ageing people. We measured suprathreshold visual efficiency i...
Article
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Purpose: The aim of this article is to propose a quantitative methodology for determining a criterion to discriminate the nonsurgical nuclear cataract from the surgical one taking into account objective measures of intraocular scattering in patients with good visual acuity (>0.6). Methods: Two groups of subjects were taken into account: a contro...
Article
Full-text available
In a previous work (Opt. Appl. 39(2), 2009, pp. 415-428) we established the characteristics that a computer-based contrast sensitivity function (CSF) measurement system has to be used in the opthalmological clinic. In order to obtain a generalized use of CSF in clinics and as a screening tool, the necessity to incorporate a normality range by age w...
Article
Full-text available
Purpose: The aim of this article is to propose a quantitative methodology for determining a criterion to discriminate the nonsurgical nuclear cataract from the surgical one taking into account objective measures of intraocular scattering in patients with good visual acuity (40.6). Methods: Two groups of subjects were taken into account: a control g...
Article
Full-text available
In this work we introduce a new category of barriers that we call "functional vision barriers." This expression refers to lighting and visual elements that may complicate or hinder functional vision and may make life even more difficult for people with visual defects. These barriers appear as a consequence of certain negative effects caused by the...
Article
It is known that temporal modulation of the source illuminating a scene can affect visual performance. Nevertheless, there is a lack of evidence showing this in a natural setting with a simple, natural task. We devised a simple test of visual function using a pencil and paper visual search technique − identifying low-contrast printed numbers on the...
Article
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A glare source in the visual field modifies the brightness of a test patch surrounded by a mesopic background. In this study, we investigated the effect of two levels of transient glare on brightness perception for several combinations of mesopic reference test luminances (Lts) and background luminances (Lbs). While brightness perception was affect...
Article
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The presence of a glare source in the visual field produces a veiling luminance (L<sub>v</sub>), which generates a brightness reduction that can be expressed in terms of the glare index (V). The relation between the veiling luminance caused by glare and the apparent brightness reduction of a reference target has already been established for steady...
Article
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In this study we present the comparison of the performance of two systems to measure intraocular scattering. Measurements were made by using a psychophysical system based on a brightness comparison method that provides a glare index and a physical system based on the double-pass technique, which gives an objective scatter index by measuring the opt...
Article
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Visual performance is defined as the speed and accuracy of processing visual information. Existing models of visual performance evaluate illuminated tasks in terms of luminance contrast, retinal illuminance and visual size but do not consider the chromatic properties of the task. In consequence, there is no recommendation for the chromatic contrast...
Article
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When a bright light is present in the field of view, visibility is dramatically reduced. Many studies have investigated the effect of glare on visibility considering foveal vision. However, the effects on peripheral vision have received little attention. In a previous work [J. Opt. Soc. Am. A 25, 1790 (2008)], we showed that the effect of glare on...
Conference Paper
Full-text available
Background / Purpose: A Transitional Space (TS) – from exterior to interior – becomes a “lighting barrier” due to the extreme lighting conditions involved. Considering the increase in the adaptation time with ageing, strong illumination change effects will dependon peoples age.An experiment was performed to test this dependency. We measured the t...
Article
Full-text available
Transitional spaces (TS) are characterized by possession of high gradients of luminances between inside and out, which places a great demand on the users’ visual system's function. A satisfactory descriptive indicator of this kind of situation could be a ‘modelling factor’ (MF), defined from cylindrical illuminance and horizontal illuminance measur...
Article
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Temporal modulation of lighting at frequencies higher than the critical fusion frequency can affect human efficiency in diverse ways that are not understood. A simple visual search task was used to assess visual performance under lighting with low (3%) and high (32%) temporal modulation and compared with the results of a conventional discrimination...
Article
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We measured at the fovea the chromatic contrast threshold for stimuli modulated along different chromatic directions in the isoluminant plane of MBDKL colour space, considering the two cardinal axes (L/M) and S/(L + M) and other intermediate non-cardinal directions. This psychophysical determination was conducted as a function of stimulus size. The...
Article
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The purpose of this study was to compare the performance of two psychophysical contrast sensitivity tests, one based on a computerized system – FVC 100 – and the other based on printed charts – VCTS 6500, both using the discrimination of sinusoidal grating orientation under photopic adaptation. Altogether, 45 eyes of 23 people with ages ranging fro...
Article
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We have shown that, in the mesopic range, glare reduces the perceived brightness of a foveal test patch in a non-linear fashion (Colombo, Barraza, Issolio, LR&T, 32(2), 2000). Here we report the effects of glare measured under a variety of different contrast conditions obtained by modifying the background luminance. The experiment was carried out u...
Article
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Purpose. It was shown previously that a peripheral glare source reduces the brightness of a foveal test. This reduction of brightness cannot be explained by a luminance match. In this work we performed an experiment to test the hypothesis that our brightness evaluation task is affected by lightness intrusion. Methods. Using a magnitude comparison m...
Article
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Purpose: Previous results have shown the influence of glare on the brightness evaluation of a foveal test in the mesopic range depends on the test luminance as well as the surround luminance. In this work we perform new experiments in order to find which variable determines lightness constancy. Methods: Patches subtending 1.2 degrees placed on the...
Article
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Purpose: When the grey target of a White's display overlaps a pair of adjacent black and white stripes, an illusory contour appears as the continuation of the border between the stripes, but with the contrast polarity reversed. This effect accounts the hypothesis that when two aligned contours undergo a discontinuous change in the magnitude of cont...
Article
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We present a series of experiments exploring the effect of chromaticity on reaction time (RT) for a variety of stimulus conditions, including chromatic and luminance contrast, luminance, and size. The chromaticity of these stimuli was varied along a series of vectors in color space that included the two chromatic-opponent-cone axes, a red-green (L-...
Article
Purpose. The reduction of visual performance due to glare was traditionally modeled by adding to the stimulus a uniform veiling luminance (Lv), which reduces the effective contrast of the image. We investigate whether this model can account for the increase of simple reaction times obtained when a steady glare source is presented in the periphery o...
Article
Full-text available
We systematized the study of the effect of glare on reaction time (RT), for visual conditions similar to the ones found during night driving: Mesopic range of adaptation 0.14 cd/ m 2 , glare levels of the order of those produced by car headlights (E G = 15, 60 lx), suprathreshold luminance contrasts, and a variety of spatial frequencies covering th...
Article
Full-text available
When a myopic or hyperopic eye wearing an ophthalmic lens looks at a stimulus and also receives light from a peripheral point, the lens modifies the eccentricity angle with which light originated at this point reaches the eye. Under paraxial approximation, the lens visual magnification (quotient between the angles subtended at the corneal vertex by...
Article
Full-text available
In this work, we evaluate the feasibility to determine the intraocular scattering by measuring the brightness reduction by glare. A haploscopic system based on the brightness comparison has been developed. This system allows to compare the brightness of a test with a steady glare source in the field of vision, and another one without it. Our goal i...
Article
Full-text available
To study the influence of glare on the visual performance of a subject wearing an ophthalmic lens, it is useful to know how the lens affects the illuminance reaching the eye. In this paper, considering spherical standard ophthalmic lenses and defining the relative illuminance, Er, as the quotient between the illuminance at the cornea with and witho...
Article
We present a series of experiments exploring the effect of the stimulus spatial configuration on speed discrimination and two different types of segmentation, for random dot patterns. In the first experiment, we find that parsing the image produces a decrease of speed discrimination thresholds such as was first shown by Verghese and Stone [Verghese...
Article
Full-text available
We discuss the characteristics a system to measure the contrast sensitivity function (CSF) in the ophthalmologic clinic has to have. We propose that this system should be computer based in order to assure flexibility and precision. Besides the original calibration, this equipment needs an auxiliary system to keep the working conditions allowing per...
Article
Full-text available
The effect of intraocular scattering of light generated at a peripheral glare source is quantified using a model empirically formulated in terms of the veiling luminance. This luminance is directly proportional to the illuminance generated at the eye by this source and inversely proportional to the square of the eccentricity angle subtended by the...
Article
Full-text available
This paper examines the effect of colour on reaction times for variations in both luminance and chromatic contrast. Results confirm the idea that reaction times are determined by a cone-opponent mechanism: Reaction times generated in response to S-cone isolating stimuli are the longest, whereas the shortest reaction times are generated by L—M-cone...
Article
Full-text available
We systematized the study of the effect of glare on reaction time (RT), for visual conditions similar to the ones found during night driving: Mesopic range of adaptation (0.14 cd/m2), glare levels of the order of those produced by car headlights (E(G)=15, 60 lx), suprathreshold luminance contrasts, and a variety of spatial frequencies covering the...
Article
Full-text available
The knowledge of the functioning characteristics of light sources can help a designer make better decisions when it comes to the type of lamp to be used under the given conditions of each installation, and it may help achieve better employment of them. That is why the objective of the present work is to explore how chromatic characteristics are mod...
Article
Full-text available
Physiological studies of the human retina show the existence of at least two visual information processing channels, the magnocellular and the parvocellular ones. Both have different spatial, temporal and chromatic features. This paper focuses on the different spatial resolution of these two channels. We propose a neuromorphic model, so that they m...
Article
Full-text available
The amount of light captured by the eye depends on pupil size. Moreover, one of the factors determining the steady-state pupil size is ambient illumination and sudden increments of light reaching the retina cause a brisk and transient pupil constriction described as the dynamic Pupil Light Reflex response. In experiments where a glare source acts a...
Article
Full-text available
Spatial frequencies are often employed both in Fourier Optics and in Physiological Optics. According to Fourier Optics, any object can be synthesized as a superposition of harmonics of different spatial periods and the spatial frequency, defined as the inverse of the corresponding period, is measured in cycles per millimeter. On the other hand, in...