Person:
Pérez Carrasco, María Jesús

First Name

María Jesús

Last Name

Pérez Carrasco

URI

https://hdl.handle.net/20.500.14352/79893

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Óptica y Optometría

Department

Optometría y Visión

Area

Optica

Identifiers

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Now showing 1 - 9 of 9

Increase of the spatial resolution and of the contrast sensitivity for myosis induced in usual drivers demonstrates experimentally.
(2009) Sánchez Ramos, Celia; Langa Moraga, Antonio; Gómez Tortuero, E.; Pérez Carrasco, María Jesús; Colilla, E.
Human visual system is able to adapt itself to get better visual perception in a very extense lighting range, since light of the moon until brilliant sunlight, so from scotopic until photopic lighting (Walkey and Barbur, 2006). Changes in pupil size produced in response to changes in light intensity optimise the amount of light received by the retina, maximizing visual perception. This is produced along 10 log units, thanks to the human eye adaptation by biochemical and nervous mechanisms. In the light/darkness process of adaptation mechanical activity, due to pupil size variations (Myosis/mydriasis), contributes 1 logarithmic unit and is the most rapid of all contributions to the response. Between both lighting limits (photopic and scotopic), mesopic range is establised. This lighting (mesopic) is found in a natural way when night falls or at dawn, time in which driving becomes a harder task, thus its study has such an enormous interest due to its influence of driving. Mesopic vision describes the period of trnsition from rods (Scotopic) until cones (photopic) vision, in which both photoreceptors contributes to the visual response. Although it hasn´t been precisely establised by the CIE (Commission Internationale de l´Eclairage), mesopic range covers roughly 4 log units (Wyszecky y Stiles 1982; Walkey et al. 2006), which means lighting levels frecuently used in occupational ambient. In mesopic lighting condition several changes are produced in visual function. Pupil size variations distort the optic of the eye, degrading the quality of the retinal image (aberrations and light dispersion). On the other hand, the extensive spatial summation of the rods signal increases the light sensitivity but also causes a significant lost of contras sensitivity, the visual acuity of low contrast and the spatial resolution (Walkey y Barbur, 2006).
Contrast sensitivity and disability glare in patients with dry eye
(Acta Ophthalmologica Scandinavica, 2006) Puell Marín, María Cinta; Benítez Del Castillo Sánchez, José Manuel; Martínez De La Casa Fernández-Borrella, José María; Sánchez Ramos, Celia; Aladro Vico, Eva; Pérez Carrasco, María Jesús; Pedraza Aranda, Constanza; Hierro Zarzuelo, Almudena, del
Purpose: To evaluate contrast sensitivity and disability glare in patients with dry eye using the Contrast Glaretester 1000. Methods: Contrast sensitivity and disability glare were determined in 33 eyes of 33 patients with dry eye and 30 eyes of 30 healthy control subjects for six target sizes with a visual angle of 6.3-0.7 degrees using the Contrast Glaretester 1000, whose working mechanism is similar to that of the conventional perimetry instrument. Results: Contrast sensitivity was significantly worse in dry eye group when viewing all target sizes (reduction of 0.10-0.25 log contrast units, p < 0.01) except at 6.3 degrees. In the presence of glare, differences in log contrast sensitivity between the groups (0.10-0.25 units) were significant (p < 0.01) for all target sizes, with the dry eye group showing worse results. The reduction in contrast sensitivity induced by glare (disability glare) was significantly worse in the dry eye group versus the control group but only for the 2.5-degree size target, where 0.14 log contrast units were lost. Conclusions: Contrast sensitivity with and without glare was significantly reduced in patients with dry eye compared with control subjects, but the number of log contrast units lost with glare (disability glare) was similar in the two groups, except for the 2.5-degree size target.
Enhancing contrast sensitivity with polarized filter in sports with glare produced on flat surfaces under photopic conditions.
(2007) Sillero, M.; Langa Moraga, Antonio; Moral Martínez, I.; Pérez Carrasco, María Jesús; Sánchez Ramos, Celia
INTRODUCTION: Reflections of light on flat surfaces foten generate central glare during sport practice (i.e. skiing, fishing or driving). Polarized filters are mounted in googles or spectacles to neutralize the effects of glare on these situations, but only empiral data from the manufactures and subjective evaluations probe the ffectiveness of polarized filters under reflected glare on flat surfaces. There is a lackk of information in literature about physiological effects of polarized filters on vision. METHODS: 52 physically active subjects (40 males and 12 female; 22.16 +- 6.89 years) with normal vision (Visual Acuity Snellen coefficient= 1.08 +-0.28) performed the test, seated with their head placed on a chin-rest located 1.76 meters away from a Pelli-Robson contrast sensitivity chart, which was placed on the floor. In order to generate the central glare, we projected a collimated light bearn onto the chart. Binocular contras sensitivity was recorded with the subject wearing spectacles fifted with a standard polarized filter, with coloured filter- both of them with the same transmitance- and without filter. The dazzling light hit the test surface first at an angle of 31.5º with respect to the horizontal (Brewster angle) and then at 46.6º, 37.6º, 23.8º and 17.2º. Both the visual an angle conditions were randomized to avoid glare, tiredness and memorization effects on the results. RESULTS: results show how the effect of glare was neutralized by the polarized filter- with values close to reference levels recorded without glare- but not by the coloured filter, which gave rise to similar contrast sensitivities as for the uncovered eyes. The benefits of polarized filters were reduced- but were still significant in all the cases- as the angle of incident light was varied from the Brewster angle. DISCUSION: Our ecological approach achieved controlled yet realistic, polarized reflected central glare on the test surface, which prevented subjects from properly seeing the target. This scenario difered from most reports in the literature, in which glare is generated by a diffuse light source, escentric to the test target. Our results probe by fist time, in physiologically terms, the benefits of using polarized filters to improve contrast sensitivity in the presence of glare produced on horizontal sufaces under photopic light conditions.
Straylight in older drivers.
(2009) Sánchez Ramos, Celia; Colilla, E.A.; Gómer Tortuero, E.; Langa Moraga, Antonio; Pérez Carrasco, María Jesús
The measures of the dazzle and of the dispersion of the light intraocular are particularly important for the drivers and affected subjects of cataracts. The technology of measure of the strylight values the dispersion of the light for psycophysical methods allos to know the state of the visual function of olders drivers. The aim is to evaluate de validity of the measure of the dispersion of the light intraocular as enough indicator to determine the visual capacity of the drivers´s in conditions mesópica.
Efecto de un filtro amarillo sobre la función visual mesópica de sujetos emétropes y sujetos miopes operados de cirugía refractiva lasik
(2007) Pérez Carrasco, María Jesús; Puell Marín, María Cinta
OBJETIVO: Analizar la influencia de un filtro amarillo con tratamiento antirreflejante sobre la función visual mesópica de sujetos emétropes y sujetos miopes operados de cirugía refractiva LASIK. MÉTODO: En la 1 etapa de la investigación, se estudió 1 muestra homogénea compuesta por 38 emétropes adultos, a los que se midió la sensibilidad al contraste (SC) (Vistech VCTS 6500), agudeza visual (AV) de bajo contraste (Microlens UPT-1000) y sensibilidad luminosa diferencial (SLD) (Octopus 1-2-3) en el campo visual central (30) sin/con la interposición de un filtro amarillo (X-482) con tratamiento antirreflejante en condiciones mesópicas. En la 2 etapa de la investigación, se valoró la SC sin/con deslumbramiento en una muestra homogénea de 27 miopes intervenidos de cirugía LASIK con un post-operatorio superior al año, y en 30 sujetos control. Las medidas se realizaron sin y con el filtro amarillo (X-482) utilizando el Mesotest II en condiciones mesópicas, y el CGT-1000 en condiciones fotópicas. RESULTADOS: Los emétropes con el filtro amarillo tuvieron un aumento de la SC mesópica para las frecuencias espaciales de 1.5 c/g (p= 0.002) y 6 c/g (p= 0.02), una mejora de la AV del 5% de contraste (p= 0.0004), y un incremento de la SLD para las áreas establecidas del campo visual central (30) (p< 0.05). En condiciones mesópicas, los sujetos LASIK presentaron un descenso de 0.14 unidades logarítmicas en la SC sin deslumbramiento. Con el filtro amarillo, esta variable aumentó significativamente (p= 0.023). Con deslumbramiento, el filtro amarillo también incrementó la SC en el grupo LASIK pero no significativamente. En condiciones fotópicas, no se observaron diferencias significativas. CONCLUSIONES: El uso de los filtros amarillos con tratamiento antirreflejante aumenta la calidad de la función visual de sujetos emétropes en el rango mesópico de iluminación y mejora la SC mesópica de sujetos miopes operados de cirugía refractiva LASIK.
Comparing noise reduction techniques for visual reflected glare.
(2007) Sillero, M.; Sánchez Ramos, Celia; Langa Moraga, Antonio; Moral Martínez, I.; Pérez Carrasco, María Jesús
Vision can be thought of as a dynamical system, whereas Mischeler (1) defines glare as a form of visual noise. In this presentation we focus on techniques for previnting disability glare on planar horizontal surfaces. This is a glare which results in a reduced ability to obtain the visual information required for a particular activity due to decreased contrast and visibility. We present two expreiments (2) in which we analyze the effectiveness of different techniques for filtering reflected glare. The techniques we investigated consist of a optical form of real time noise reduction in which the aim is to minimize the information loss.
Differences in the myosis response to increased light intensity using the x-480 filter in persons over 65 years old.
(2009) Sánchez Ramos, Celia; Díaz de Cerio, E.R.; Bonnin Arias, Cristina Natalia; Díaz Serrano, Y.; Vinas Pena, M.; Molina Gómez, C.; Pérez Carrasco, María Jesús
PURPOSE: To assess the effect of the X-480 filter (Cutoff 480nm) on mesopic and scotopic pupil diameters in persons older than 65 years, we examined 196 eyes of 98 subjects (52 men/46 women) aged 65 to 101 years.
Analysis of intra-observer´s repeatability in retinopathy´s classification of patients with, both, clear and yellow IOL´S implantation.
(2009) Pérez Carrasco, María Jesús; Sánchez Ramos, Celia; Vinas Pena, M.; Bonnin Arias, Cristina Natalia; Forlan, A.; San Miguel, M.; Ramírez, G.
PURPOSE: to discriminate between different moderate retinopathies according to the clinical Age-Related Maculopathy Staging System (CARMS) using for it retinographies. Also to analyze de intra-observer`s reliability. METHODS: 808 retinographies were made to 101 subjects (both gender). Every patient had suffered cataract surgery with clear and yellow IOL´s implantation, 55 retinographies were classified by using CARMS system, which categorizes the images depending on the Drusen´s presence or absense, retinal pigment epithelium irregularities, geographic atrophy, pigment epithelium detachment and choroidal neovascularisation. The 55 retinographies categorizing was made by 2 experts in a blind, independent way. The method followed consisted in 2 different sequences with every of the 3 evaluated systems. The goal of the doubled-classification-method, with changing order no randomised, was to reject the influence of the evaluation of the previous image in the following one (Velo´s effect). Inter-observer´s repetability was checked, because of Kappa index was calculated, as an agreement parameter between both Experts. RESULTS: Intra-observer´s reliability analysis was the following: CARMS concondance obtained was 87.27% for observer A and 95.45% for the observer B. The expected concordance was 57.36% and 57044% for A and B respectively. Kappa index was 0.7016 and 008932 for A and B respectively. Drusen`s concordance obtained for observer A eas 87.27% and 98.18% for observer B. The expeted values were 59050% and 61.16% for A and B respectively. Kappa index was 0.6857 and 0.9532 for A and B respectively. Pigmentation´s concordance obteined was 87027% and 92.73%, for A and B observers. The expected concordance was 55021% and 53.72% for A and B and Kappa indexes were 0.7159 and 0.8429 for both. The reliability measured by Kappa index followed the rule: 0.80-1.00 (Excellent), 0.60-0.80 (Good), 0.40-0.60 (Moderate), 0.20-0.40 (Low), <0.20 (Bad). CONCLUSIONS: Kappa´s indexes obteined for the intra-observer analysis show a good reliability, between Godd and Excellent. A higher discrepancy in the firs retinas, which were classified, was observed. This means that a previous trainins is necessary.
Efectividad de los filtros polarizados frente a los coloreados en la Sensibilidad al Contraste bajo condiciones de deslumbramiento central por reflexión.
(Ver y Oír, 2008) Sillero, Manuel; Moral Martinez, Inmaculada; Langa Moraga, Antonio; Pérez Carrasco, María Jesús; Sánchez Ramos, Celia
La efectividad de los filtros polarizados frente al deslumbramiento central por reflexión ha sido demostrada sólo mediante test empíricos de laboratorio, pero no desde el punto de vista fisiológico. En este trabajo se midieron, en 96 sujetos adltos de un amplio rango de edad, los efectos del deslumbramiento central por reflexión y en ausencia de él, con filtros polarizados, filtros coloreados y sin filtros, utilizando un protocolo original próximo a las condiciones de la vida real. La aproximación ecológica confirma que los filtros polarizados son significativamente más efectivos que los coloreados frente al deslumbramiento central por reflexión.