Maria José Luque

• University of Valencia

Clinical relevance: Age-related baseline data are important in clinical optometry as a reference against which vision abnormalities can be diagnosed. Background: Contrast Sensitivity Function (CSF) is important for detecting age-related vision diseases. However, existing studies often overlook elderly populations under a range of testing situati...

Background Active vision therapy for amblyopia shows good results, but there is no standard vision therapy protocol. This study compared the results of three treatments, two combining patching with active therapy and one with patching alone, in a sample of children with amblyopia. Methods Two protocols have been developed: (a) perceptual learning...

In recent years, there has been intense development of digital diagnostic tests for vision. All of these tests must be validated for clinical use. The current study enrolled 51 healthy individuals (age 19–72 years) in which achromatic contrast sensitivity function (CSF) in near vision was measured with the printed Vistech VCTS test (Stereo Optical...

In this article, the Islamic gold coins collections of the University of Valencia is studied for the first time for its elemental composition and colorimetric properties. To that end, non-destructive elemental analysis using energy-dispersive X-ray fluorescence is applied to obtain the coins’ elemental profile. Additionally, the colour of the coins...

Citation: Briceno-Lopez, C.; Burguera-Giménez, N.; García-Domene, M.C.; Díez-Ajenjo, M.A.; Peris-Martínez, C.; Luque, M.J. Corneal Edema after Cataract Surgery. Abstract: This systematic review investigates the prevalence and underlying causes of corneal edema following cataract surgery employing manual phacoemulsification. A comprehensive search e...

Background To evaluate factors associated with better outcomes from optical treatment alone in amblyopic children from 3 up to 7 years. Methods Data extracted from two studies with similar protocols, Amblyopic Treatment Studies 5 (n = 152) and 13 (n = 128) from the Pediatric Eye Disease Investigator Group database, were used to determine by regres...

Aim: To compare the visual perception (color and chromatic-achromatic contrast vision) of a small cohort of COVID-19 patients at the time of infection and after 6mo with that of a healthy population matched for sex and age. Methods: A total of 25 patients (9 females, 16 males, mean age: 54±10y) with COVID-19 hospitalized in the COVID-19 Unit of...

A low-cost new instrument to carry out automated colorimetric analysis has been developed. The device consists of a carousel sampler, built by a 3D-printer, and a Raspberry Pi4-controlled signal measurement module based on the RGBC (red, green, blue and clear) responses of a TCS34725 color light-to-digital converter with IR filter. The device has b...

Purpose: to assess anterior scleral thickness (AST) across diverse scleral meridians and to evaluate the relationship with corneal biomechanical response and several ocular parameters. Methods: This prospective non-randomized study comprised 50 eyes of 50 patients (mean age, 29.02 ± 9.48 years). Anterior scleral thickness was measured meridionally...

Purpose: The aim of our study was to assess the visual quality of pterygium patients with total ocular aberrations, and not only corneal aberrations. Methods: 46 eyes of 37 pterygium patients (mean age 48 ± 15 years) were evaluated in a retrospective study. Inclusion criteria were primary pterygium, without any previous surgical treatment. Before s...

Resumen: En este trabajo se ha desarrollado un método para cuantificar quinina mediante fluorescencia con Smartphone. El procedimiento implica solo la necesidad de una linterna de luz ultravioleta (396 nm), una caja de porexpán, una cubierta plástica con recubrimiento interno de terciopelo negro y un Smartphone. El método proporciona un límite de d...

Purpose: to assess anterior scleral thickness (AST) across diverse scleral meridians and to evaluate the relationship with corneal biomechanical response and several ocular parameters. Methods: This prospective non-randomized study comprised 50 eyes of 50 patients (mean age, 29.02 ± 9.48 years). Anterior scleral thickness was measured meridional...

Background To assess visual quality and stabilization of refractive changes in corneal edema patients after cataract surgery, using visual acuity (VA) and contrast sensitivity measurements. Methods Sixty-one eyes were analysed, twenty-three with and thirty-eight without corneal edema. Uncorrected and corrected distance VA (UDVA and CDVA) were dete...

The use of microlens arrays for lightfield display has the drawback of providing images with strong chromatic aliasing. To overcome this problem, pinhole-type lightfield monitors are proposed. This paper is devoted to evaluating the capability for such lightfield monitors to offer the user a convincing 3D experience with images with enough brightne...

We have assessed the spectral transmittance of the different layers of the human cornea in the ultraviolet (UV), visible, and near-infrared (IR) spectral ranges. Seventy-four corneal sample donors were included in the study. Firstly, the corneal transmittance was measured using a spectrophotometer. Then, all samples were fixed for histopathological...

(1) Purpose: To assess the main corneal response differences between normal and subclinical keratoconus (SCKC) with a Corvis® ST device. (2) Material and Methods: We selected 183 eyes of normal patients, of a mean age of 33 ± 9 years and 16 eyes of patients with SCKC of a similar mean age. We measured best corrected visual acuity (BCVA) and corneal...

Purpose To evaluate whether tobacco affects color vision in young moderate smokers. Methods Chromatic mechanisms of 13 moderate smokers (10–20 cigarettes/day and at least 5 years smoking) and 17 non-smokers in the 18–35 age range were assessed with the Farnsworth-Munsell 100-hue (FM100h) test and short wavelength automated perimetry (SWAP). Resul...

Contrast sensitivity (CS) in children is not routinely measured in the clinical setting, although CS losses have been found in amblyopic and premature children. Thus simple visual acuity measurements do not completely assess their quality of vision. To evaluate contrast sensitivity in children, a reliable and easy test, sampling the entire spatial...

Amblyopia influences psychomotor and psychosocial skills, although not all studies are unanimous. Different treatments coexist, but the effect on those variables is not clear. This study aims to probe whether children with amblyopia have impairments in these areas and if different optometric treatments reduce them effectively. 50 children, diagnose...

Video projectors allow interesting applications in vision sciences since they provide a large projection area. We have colorimetrically characterized a LCoS projector using a mathematical model requiring additivity and constancy of the primaries -a sigmoid function in our case. Significant differences in chromaticity in the CIELAB space, but not in...

Purpose To develop and validate a new iPad-based color vision test (Optopad). Methods A total of 341 student eyes were enrolled in a first comparative study between Optopad and the Isihara tests. In a second comparative study, Optopad vs. the Farnworth-Munsell test (FM 100H), a total of 66 adult eyes were included. Besides the agreement between te...

Significance: Apple devices could be suitable for vision tests, provided that the test has been correctly adapted to the device, after considering the spatial and colorimetric characterization of the screen. Purpose: The majority of vision applications has not been developed by vision or colorimetry experts and suffers from conceptual and design...

Purpose: To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. Methods: All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical cohe...

In the present study, we have designed and tested a perimeter for the detection of damage in the chromatic mechanisms using a video projector. To this purpose, we have characterized pixel to pixel a video projector, to account for the inhomogeneities in the projection. We have measured the tristimulus values of the projector primaries as a function...

Purpose: Available applications for vision testing in mobile devices usually do not include detailed setup instructions, sacrificing rigor to obtain portability and ease of use. In particular, colorimetric characterization processes are generally obviated. We show that different mobile devices differ also in colorimetric profile and that those dif...

Some diseases that affect the visual system may show loss of chromatic-achromatic sensitivity before obvious physical signs appear in the usual examination of the eye's posterior segment. A perimetric study has been conducted with four typical patients with glaucoma and diabetes, at different stages of the disease. In addition to the standard white...

It is well-known the advantages of measuring chromatic and achromatic contrast sensitivity for detecting pathologies. But these measurements are rarely used in clinical practice, due the complexity of the measurements and the examinator specialization. In fact, there is not a complete characterization of the response of the visual pathways to achro...

Background In this study, the reliability of perimetric contrast sensitivity measurements favouring the achromatic, the red-green and the blue-yellow post-receptorial mechanisms was analysed.MethodsA new technique, multichannel ATD perimetry, provides spatial and temporal stimuli favouring the detection by an achromatic mechanism (A), from a magno...

Purpose In this study, we describe contrast sensitivity losses in the visual field of a patient affected by chloroquine toxicity, measured with stimuli favoring different visual mechanisms. We have compared these results with those of other, usual clinical tests. Methods The vision of a patient who underwent ten years of chloroquine treatment was...

We have designed a configurable stand-alone Matlab-based software to simulate dichromatic perception of video streams. The algorithm used is an extension for video streams of the “corresponding pair algorithm” by Capilla and coworkers for simulation of dichromatic perception of images. The software allows the user to upload a video sequence and to...

Purpose: To evaluate visual function with a novel multichannel functional test named the ATD Multichannel Functional Test. Methods: This multicenter study had a prospective and cross-sectional design. A total of 186 eyes were included: 42 with glaucoma, 14 glaucoma suspects due to optic nerve characteristics, 25 ocular hypertensives, and 105 nor...

Purpose: We aim to simulate how colored images are perceived by subjects with local achromatic and chromatic contrast sensitivity losses in the visual field (VF). Methods: The spatiochromatic corresponding pair algorithm, introduced in a previous article (J Opt Soc Am (A) 2004;21:176-186), has been implemented with a linear model of the visual s...

We measured contrast sensitivity (CS) to sinusoidal spatio-temporal patterns isolating the red-green and blue-yellow mechanisms, at 21 locations in the visual field (including the fovea). These measurements complete the available data for the red-green mechanism at fovea and for both mechanisms outside fovea with non-stationary patterns. Chromatic...

We simulate how subjects with losses in chromatic and achromatic contrast sensitivity perceive colored images by using the spatiochromatic corresponding pair algorithm. This is a generalized version of the algorithm by Capilla et al. (J Opt Soc Am (A) 2004;21:176-186) for simulating color perception of color deviant subjects, which incorporates a s...

We have developed a configurable tristimulus colorimeter for its use as a practical teaching tool for Color Science and Visual Psychophysics. It is a set of functions for Matlab® for the generation of colorimetrically controlled stimuli in a display, based on the Colorlab 1.0 library, with which any generable colour can be matched by a mixture of t...

In this work, the metric of a new multistage colour vision model, ATTD05, is assessed and a new colour difference formula is suggested. Firstly, the uniformity of the ATTD05 colour space was compared with that of CIECAM02 for some Munsell samples, because if the model yields a uniform perceptual space, we will be able to implement a colour differen...

Evaluating visual fields of patients by means of a perimeter, computerized or not, requires total colaboration from the subject. Obviously, uncooperative patients yield unreliable results and, therefore, the clinician cannot extract useful information from the perimetry, to use, in addition to other clinical test, to diagnose a pathology. But, unde...

We add a simple model for spatial vision to our original corresponding pair algorithm to simulate the colour appearance of an image, as seen by a subject with variant (abnormal) vision. In this way, the perception of coloured images by subjects having their spatial vision altered by a pathology, may be simulated, both for normal and dichromatic col...

From a reduced set of experimental measurements, we have developed an algorithm that generates a mosaic of color discrimination ellipses, densely covering the region of the chromaticity diagram defined by the phosphors of a CRT monitor, with minimum overlapping between ellipses and leaving the minimum uncovered space. To test how well this mosaic c...

The aim of this work is to study the uniformity of the perceptual space of the multistage neural colour vision model ATTD05 by comparison with CIECAM02, which is the latest colour appearance model adopted by the CIE. A set of parameters describing the deformation suffered by the loci of constant chroma and hue of the Munsell Atlas, were used to mea...

Tinted lenses increasingly used in many activities, both during leisure time and for work, out in the open and indoors. Our aim is to test if any tinted lens is more advisable than another, and if the choice of colour depends on the age group.

Purpose: The new ATD perimetry assesses contrast sentivity thresholds for the three afferent sensory pathways of the visual system. Our aim is to compare contrast sensitivity to stimuli with different spatio‐temporal frequencies in glaucomatous (G) and ocular hypertensive (OHT) subjects. Methods: Twenty three G and OHT subjects were selected from t...

This work uses the S-CIELAB color model to compare images that have been calibrated and processed using a colorimetric dithering method which simulates increments in viewing distance. Firstly, we obtain XYZ calibrated images by applying the appropriate color transformations to the original images. These transformations depend on whether the image i...

Several methods to determine the color gamut of any digital camera are shown. Since an input device is additive, its color triangle was obtained from their spectral sensitivities, and it was compared with the theoretical sensors of Ives-Abney-Yule and MacAdam. On the other hand, the RGB digital data of the optimal or MacAdam colors were simulated t...

We found that yellow filters reduce the mean brightness of a set of coloured samples significantly less with blue surrounds than with black, achromatic or yellow ones, in comparison with the naked eye and less than a yellow surround in comparison with a luminance-matched grey filter. The predictions of Hunt's model and Guth's ATD95 agree with these...

The color solid includes all colors perceived by the human visual system associated to physical color stimuli. The optimal or MacAdam colors define its frontier. However, the MacAdam limits, and therefore the shape and volume of the color solid, depend on the illuminant or real light source, even in a uniform color space. In general, the greater th...

We have analized the chromatic vision and the contrast vision of subjects older than 50 years wearing coloured lenses, in order to compare the performance of these kind of filters when used by this particular population. “PsychoWin 2.25” and “Cambridge Colour Test” (CCT) from Cambridge Research Systems were used to determine the contrast sensitivit...

Different hypotheses on the sensitivity of photoreceptors and post-receptoral mechanisms were introduced in different colour vision models to derive acceptable dichromatic versions. Models with one (Ingling and T'sou, Guth et al, Boynton) and two linear opponent stages (DeValois and DeValois) and with two non-linear opponent stages (ATD95) were use...

The dichromatic color appearance of a chromatic stimulus T can be described if a stimulus S is found that verifies that a normal observer experiences the same sensation viewing S as a dichromat viewing T. If dichromatic and normal versions of the same color vision model are available, S can be computed by applying the inverse of the normal model to...

Since an input device is not a colorimeter and its opto-electronic behavior is not ideal, its color gamut is smaller than that of the CIE- 1931 XYZ standard observer. A chromatic discrimination model and packing algorithm to the color discrimination ellipses have been used to compute the number of distinguishable colors within the frontiers of MacA...

Tinted lenses for everyday use should not impair visual acuity and contrast sensitivity or cause radical changes in color perception. The main aim of this study was to compare the performance in contrast detection and color discrimination tasks of a set of tinted lenses with that of gray filters of equal luminance under D65. The contrast sensitivit...

We have compared corresponding pairs obtained by simultaneous matching (haploscopic matching) and by memory matching (after 10 min) using 34 reference tests selected from the Munsell Atlas (glossy), belonging to the four main hues 5Y, 5G, 5PB, and 5RP. These colours lie very close to the F1 and F2 axes in the SVF space, where we have analyzed our r...

In this work, we have examined the influence of different parameters both on perceived saturation and saturation discrimination with unrelated colours, on the basis of S. L. Guth's CA90 colour-vision model and its subsequent modifications. Our analysis of perceived saturation covered (1) spectral saturation functions at constant luminance, (2) satu...

Classically the visual system sensitivity has been studied separately as a function of spatial frequency and orientation, without explicitly pointing out the relation between both parameters. As the visual system processes two-dimensional signals, its Contrast Sensitivity Function (CSF) is intrinsically two-dimensional too, and therefore, the depen...

In this work, we analyse and compare several linear and nonlinear colour representation spaces at different physiological levels, show the relationships between spaces and discuss the mathematical properties they should exhibit. At the photoreceptor level, we examine the cone excitation and the cone contrast spaces. We discuss the second-stage spac...

The choice of the representation space is relevant when analysing the results of a colour memory experiment. If we are interested in determining which colours are best or worst remembered using the colour difference between the reference and matching stimuli, we need spaces with a high degree of uniformity. In this paper, the results of a previous...

Les risques potentiels pour la santé liés à l'emploi d'écrans de visualisation sont une des préoccupations principales pour les millions de travailleurs qui s'en servent dans leurs activités professionnelles quotidiennes. Sur un groupe de 400 personnes non presbytes qui utilisaient des écrans, nous avons réalisé une étude à double objectif: 1) enqu...

In agreement with the principles of the relativistic model proposed by Creutzfeldt et al., with the photometric rule (lightness anchoring rule) and with the influence of simultaneous contrast in the appearance of a visual scene, we propose a first-stage mechanism yielding substantial colour constancy. We have defined a set of first-stage colour des...

The brightness changes induced in red and green tests by an achromatic surround were studied using a nulling method. The amplitude of the nulling modulation was found to increase approximately linearly with the temporal contrast of an inducing field of constant average luminance. The amplitude of the nulling modulation relative to the amplitude of...

Brightness changes induced in red or green tests by an achromatic surround were studied by a nulling method with a centre — surround spatial configuration. The amplitude of the cancelling modulation was found to increase linearly with the contrast of the inducing field when its mean luminance was constant. The quotient between the amplitudes of the...

1 It is provided a method for color image compression based on the following key steps: (1) expressing the coefficients of local space-frequency representation of achromatic and chromatic opponent channels in perceptually meaningful contrast units, (2) apply-ing divisive normalization non-linearities including relations among the coefficients of th...

Doctor Moliner s/n – 46100 Burjasot -Valencia PALABRAS CLAVE: laboratorio virtual, percepción visual, matlab, software libre, docencia RESUMEN El gran auge de los laboratorios virtuales frente a los presenciales nos impulsa como docentes a plantearnos su aplicación en el desarrollo de nuestras asignaturas, con los correspondientes problemas a la ho...