Complete algorithm for the calculation light patterns inside the ocular media

Realistic mathematical models are of great importance for studying the optical performance of the human eye. Light propagation algorithms provide robust methods to calculate field distributions inside a homogeneous medium, and thus they can be applied to the study of light patterns inside the anterior and posterior chambers of the eye. Dealing with real eyes implies using very short propagation distances together with highly refractive power surfaces. Thus, the general solutions of the field equation are used instead of paraxial Fresnel solutions. Conditions of application and sampling conditions of the method are clearly stated here. Numerical evaluation of the different refractive surfaces is also analysed. The main result is that a complete algorithm to obtain light patterns at any axial distance inside the eye is proposed. The method uses real corneal measures and axial distances together with crystalline models. Statistical results and individual predictions show the validity of the model. Application of the method is illustrated with the study of a bifocal intraocular lens.This work has been partially supported by the Conselleria de Cultura, Educació i Esport of the Generalitat Valenciana, through project GV04A/578

Rotura de un aneurisma de arteria esplénica. A proposito de un caso y revisión de la literatura

La prevalencia de aneurismas esplénicos en la población general es del 0,8%, siendo más alta en mujeres que en hombres. El embarazo, la fibrodis plasia arterial y la hipertensión portal, con o sin esplenomegalia asociada, son factores de riesgo conocidos asociados al desarrollo de aneurismas esplénicos. Se presenta el caso clínico de una pa ciente nulípara de 24 años, sin factores de riesgo vasculares y con antecedentes de paludismo, que acudió al servicio de urgencias de nuestro centro por presentar dolor abdominal tras un vuelo en avión de larga distancia. La exploración física y las pruebas complementarias realizadas mostraron un shock hipovolémico por hemoperitoneo. A pe sar del tratamiento de apoyo, la paciente falleció antes de su entrada en quirófano. La necropsia mostró la rotura de un aneurisma sacular de la arteria esplénica como causa de muerte. Se discu te la posibilidad de que un barotrauma pueda ha ber sido la causa de rotura aneurismáti

Determinación de la aberración cromática longitudinal en ojos humanos

En este trabajo, el Grupo de Óptica y Ciencias de la Visión de la Universidad de Alicante muestra los últimos resultados obtenidos en su línea de trabajo. Los autores calculan la aberración cromática longitudinal mediante el cálculo de patrones de luz propagados a través del ojo encontrando dichas distribuciones, tanto en amplitud como en fase, en un plano cualquiera del interior del ojo humano del cual se conocen su topografía corneal y sus medidas biométricas. Se ha modelado la dependencia de todos los medios oculares con la longitud de onda siguiendo la ecuación de Cauchy. Los autores han realizado el estudio de diez sujetos y han comparado los resultados con medidas reales de aberración cromática, mostrando la concordancia del cálculo numérico. Como muestra de la capacidad de la técnica utilizada, se ha aplicado el método al estudio de la aberración cromática de un queratocono.In this communication the authors have determined the longitudinal chromatic aberration using an algorithm for free space propagated pattern calculation. From topographical and biometric data, the algorithm is capable of provide amplitude and phase distribution of the field at any distance inside the eye. The wavelength dependence of all ocular media has been modelled through the Cauchy formula. Results from the study of ten subjects are compared with real measures of the chromatic aberration, showing a good agreement with numerical calculations. The capabilities of the technique have been demonstrated by applying the method to the study of the chromatic aberration of a keratoconus.Este trabajo ha sido financiado por la Conselleria de Cultura, Educació i Esport de la Generalitat Valenciana, a través del proyecto GV04A/578

Innovative education networking aimed at multimedia tools for geometrical optics learning

We present a purposeful initiative to open new grounds for teaching Geometrical Optics. It is based on the creation of an innovative education networking involving academic staff from three Spanish universities linked together around Optics. Nowadays, students demand online resources such as innovative multimedia tools for complementing the understanding of their studies. Geometrical Optics relies on basics of light phenomena like reflection and refraction and the use of simple optical elements such as mirrors, prisms, lenses, and fibers. The mathematical treatment is simple and the equations are not too complicated. But from our long time experience in teaching to undergraduate students, we realize that important concepts are missed by these students because they do not work ray tracing as they should do. Moreover, Geometrical Optics laboratory is crucial by providing many short Optics experiments and thus stimulating students interest in the study of such a topic. Multimedia applications help teachers to cover those student demands. In that sense, our educational networking shares and develops online materials based on 1) video-tutorials of laboratory experiences and of ray tracing exercises, 2) different online platforms for student self-examinations and 3) computer assisted geometrical optics exercises. That will result in interesting educational synergies and promote student autonomy for learning Optics.This work was supported by the Vicerectorat de Polítiques de Formació i Qualitat Educativa de la Universitat de València (Project UV-SFPIE_DOCE14-222505)

Alteraciones de la apoptosis como mecanismo patogénico en el lupus eritematoso sistémico.

[spa] La apoptosis es un proceso de muerte celular programada que está involucrada en la selección del repertorio de linfocitos T y en el mantenimiento de la tolerancia inmunológica, ya que es el mecanismo por el que se eliminan las células que podrían dar lugar a respuestas autoinmunes. Existen evidencias de que la alteración en los mecanismos apoptóticos están implicados en la patogenia y la actividad de las enfermedades autoinmunes sistémicas, de las cuales, el lupus eritematoso sistémico (LES) es la más representativa. Se han identificado en el ser humano algunos genes que codifican oncoproteínas y citocinas cuya transcripción parece ser crucial en este proceso: unos pro-apoptóticos (fas, p53 y TNF-alfa) y otros anti-apoptóticos (bcl-2 y IL-10). Se sospecha que cambios en la expresión de los mismos podrían desempeñar algún papel en la patogenia del LES, al favorecer la proliferación de determinadas poblaciones celulares de efecto autorreactivo.Con los trabajos de la presente tesis doctoral nos propusimos: determinar la implicación de los oncogenes (bcl-2, fas y p53) y las citocinas (IL-10 y TNF-alfa) en la disregulación apoptótica que presentan los pacientes con LES; estudiar la interrelación existente entre ellos; y analizar la relación de las posibles disregulaciones de los elementos que participan en la apoptosis con la actividad de la enfermedad lúpica.Los resultados obtenidos muestran cómo los oncogenes fas, bcl-2 y p53, las citocinas IL-10 y TNF-alfa, y la fracción proteica soluble del Fas (sFas) tienen una notable importancia en la patogenia y la actividad de la enfermedad lúpìca. Las vías apoptóticas del Fas y p53 son independientes entre sí. Sin embargo, diversas citocinas (IL-10, TNF-alfa), oncoproteínas (Bcl-2) y fracciones proteicas solubles (sFas) pueden ser las encargadas de relacionarlas entre sí. La interferencia de estas vías apoptóticas produciría una eliminación deficiente de los linfocitos autorreactivos. Ello favorecería su supervivencia, lo que provocaría las alteraciones de disregulación inmunológica propias del LES

Propagation and phase reconstruction of ocular wavefronts with SAR techniques

In this communication, we report a new method to determine the wavefront aberration function of personalized eyes. We obtain corneal surface data and axial lengths for different eyes. With these data, we construct a diffractive model of a human eye, which permits calculation of propagated light distributions at any distance inside the eye. We obtain the field at the exit of crystalline lens and extract the phase information. To unwrap this phase we use a path-following method and with the reconstructed phase we obtain the wavefront aberration function that we analyze using Zernike polynomials. The method allows linking between field patterns and wavefront surfaces that are softer and easier to analyze. To demonstrate the possibilities of the technique we have chosen five eyes which present different levels of corneal irregularities, from a quasi-spherical cornea to a very deformed one.This work has been supported by the Ministerio de Educación y Ciencia (Spain) through the project no. FIS2005-05053 and by the Conselleria de Empresa, Universitat i Ciència of the Generalitat Valencia (Valencia, Spain), through the project no. ACOMP06/099

Reconstrucción de fase en la propagación luminosa mediante técnicas SAR

Comunicación presentada en la VIII Reunión Nacional de Óptica, Alicante, Septiembre 2006.Este trabajo ha sido realizado en el marco del proyecto FIS 2005-05053 del Ministerio de Educación y Ciencia

Càlcul de la focal d'una lent divergent utilitzant el mètode indirecte

Mesurar la distancia focal d’una lent divergent utilitzant com a objecte la imatge intermèdia que proporciona una lent convergent

Scientific training of high school students: introduction to laboratory work

Póster presentado en ICERI 2010, International Conference of Education, Research and Innovation, Madrid, November 15-17, 2010.In this report, we present the obtained results in a network of collaboration between the Teaching Group in Optics and Vision Sciences DOCIVIS from the University of Alicante, composed by university professors, and a high school professor. The aim of the network is the training of high school students in laboratory practice. Main objectives consisted of, among others, promoting interest in scientific subjects and the collaboration in practical scientific training of future students of the University of Alicante. The actions carried out, can be summarized in: the search for secondary schools and teachers interested in the proposal, the joint planning of sessions, the preparation of the sketches of practices, the implementation of the practices of Physics and, finally, a satisfaction survey both for teachers and students. As a result, it was noted that 96.4% of students indicate that conducting these sessions have been very interesting, 95.5% of them believe that both discussed practical and concepts will be useful and 100% of students would like to continue conducting such sessions. All the teachers consider that the proposal was very satisfying and motivating, and they continue in this line of support.This work has been supported by the project “Proyecto Redes de Investigación en Docencia Universitaria. Convocatoria 2009-2010. Universidad de Alicante”

Determination of chromatic aberration in the human eye by means of Fresnel propagation theory

In this communication, the authors have determined the longitudinal chromatic aberrations in real eyes. The method that has been used combines real data of corneal morphology, central thickness of crystalline lens and biometric measures of axial length together with numerical calculation of the propagation process. The curvature of the crystalline lens has been adjusted to different curvature models and refractive index distributions. The wavelength dependence of all ocular media has been modelled through the Cauchy formula. Propagation through anterior and posterior chambers has been accomplished through numerical calculation of diffraction integral instead of classical ray-tracing approach. This imposes serous restrictions on the number of samples that are needed for a full propagation process. If we are only interested in amplitude calculations the method consists of evaluating propagation from cornea to crystalline lens with a spectrum propagation method. Propagation from the lens to the best image plane is accomplished by a direct calculation of Fresnel integral. With this model, we have obtained the refraction chromatic difference in diopters for several eyes. Results are compared with real measures of the chromatic aberration, showing a good agreement with numerical calculations. The capabilities of the technique have been demonstrated by applying the method to the study of the chromatic aberration of a keratoconus.This work has been partially supported by the Conselleria de Cultura, Educació i Esport of the Generalitat Valenciana, through the project nr. GV04A/578