Search results for "Acomodación"
showing 8 items of 8 documents
Influence of different types of astigmatism on visual acuity
2016
[EN] Purpose To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. Methods The lens induced method was employed to simulate a set of 28 astigmatic blur conditions on different healthy emmetropic eyes. Additionally, 24 values of spherical defocus were also simulated on the same eyes for comparison. VA was measured in each case and the results, expressed in logMAR units, were represented against of the modulus of the dioptric power vector (blur strength). Results LogMAR VA varies in a linear fashion with increasing astigmatic blur, being the slope o…
Influencia de los diferentes tipos de astigmatismo en la agudeza visual
2017
[EN] Purpose To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. Methods The lens induced method was employed to simulate a set of 28 astigmatic blur conditions on different healthy emmetropic eyes. Additionally, 24 values of spherical defocus were also simulated on the same eyes for comparison. VA was measured in each case and the results, expressed in logMAR units, were represented against of the modulus of the dioptric power vector (blur strength). Results LogMAR VA varies in a linear fashion with increasing astigmatic blur, being the slope o…
Effect of phenylephrine on static and dynamic accommodation
2018
Purpose We tested the hypothesis that changes in accommodation after instillation of Phenylephrine Hydrochloride (PHCl) observed in some studies could be caused by changes in optics. Methods We performed two experiments to test the effects of PHCl on static and on dynamic accommodation in 8 and 6 subjects, respectively. Objective wavefront measurements were recorded of the static accommodation response to a stimulus at different distances or dynamic accommodation response to a sinusoidally moving stimulus (between 1 and 3 D of accommodative demand at 0.2 Hz). The responses were characterized using two methods: one that takes into account the mydriatic optical effects on the accommodation pr…
Estudios teóricos y experimentales del efecto de las aberraciones en la profundidad de campo, la refracción y la acomodación ocular
2017
Se presentan cinco estudios relacionados con los efectos que producen las aberraciones oculares monocromáticas en distintos aspectos del funcionamiento del sistema ocular. En el primero se hace uso de un sistema de óptica adaptativa para simular la óptica ocular durante la acomodación en un ojo con la acomodación paralizada y poder así estimar la profundidad de campo del ojo durante la acomodación. Los resultados muestran que dicha profundidad varía poco durante la acomodación, y el sistema visual hace uso de ella para acomodar lo menos posible para estímulos cercanos. En el segundo se realiza un estudio teórico para ver cómo afecta la apodización en el cambio de foco que maximiza la intens…
Y salieron ilesos del fuego: Dn 3 en la obra de Romano Melodo
2020
El uso de relatos bíblicos constituye un recurso habitual dentro de la técnica compositiva del himnógrafo bizantino Romano Melodo. Por ello, en este artículo se pretende analizar la acomodación de un episodio concreto del Antiguo Testamento (Dn 3) a lo largo del corpus atribuido Romano y se cotejan los diferentes textos que pudieron ser tenidos en cuenta como fuentes.
Objective Amplitude of Accommodation Computed from Optical Quality Metrics Applied to Wavefront Outcomes
2009
Purpose: We studied the accuracy and precision of 32 objective wavefront methods for finding the amplitude of accommodation obtained in 180 eyes. Methods: Ocular accommodation was stimulated with 0.5 D steps in target vergence spanning the full range of accommodation for each subject. Subjective monocular amplitude of accommodation was measured using two clinical methods, using negative lenses and with a custom Badal optometer. Results: Both subjective methods gave similar results. Results obtained from the Badal optometer where used to test the accuracy of the objective methods. All objective methods showed lower amplitude of accommodation that the subjective ones by an amount that varied …
Effect of age in the ciliary muscle during accommodation: Sectorial analysis
2017
Abstract Purpose To compare changes in the ciliary muscle area at different sectors between pre-presbyopic and presbyopic eyes during accommodation by means of an anterior segment optical coherence tomographer (OCT). Methods The anterior ciliary muscle area was measured in 20 healthy and phakic pre-presbyopic eyes, whose mean age was 23.3 ± 4.4 years, and in 20 healthy and phakic presbyopic eyes, whose mean age was 46.5 ± 5.2 years. The relative change in the cross-sectional area of the ciliary muscle was measured at the nasal, inferior, and temporal sectors between 0 and −3 D of vergence, in −1 D step. A linear model was used to assess the correlation of each eye parameter with the accommo…
Curso de prácticas de Optometria II : práctica 4 acomodación
2020
Esta publicación surge con la finalidad de servir de guía, consulta y orientación para que el estudiantado, (o las personas interesadas en el tema), puedan ir siguiendo un orden de pruebas y de pasos durante la realización de la actividad relacionada con la evaluación de la visión binocular. Nuestro objetivo general es facilitar que se consoliden las bases prácticas necesarias para la evaluación óptima de la visión binocular en cada una de las partes que la componen. En esta publicación, correspondiente a la práctica 4, se muestra como realizar las pruebas acomodativas, permitiendo con estas pruebas conocer una parte fundamental del estado del sistema binocular.