Correcciones para la presbicia : implicaciones ópticas, perceptuales y adaptativas

Tesis de la Universidad Complutense de Madrid, Facultad de Óptica y Optometría, leída el 18-05-2016Presbyopia is the physiological inability of the crystalline lens to accommodate for objects at near distance. While accommodative lenses are the ideal solutions for presbyopia, current optical solutions rely on providing an acceptable quality of vision at near and far distances. Optimization of the optical solutions rely on better understanding of how the visual system copes with the visual quality produced by the various optical solutions. The aim of this thesis is to study optical, visual and perceptual performance of different presbyopic corrections such as alternating vision, monovision and simultaneous vision, and to study the effect of adaptation on perceptual performances. Methods: We measured and corrected ocular aberrations using custom developed adaptive optics setup, used images blurred by real aberrations of different orientation and/or magnitude and measured the internal code for blur in eyes with long term differences in blur magnitude or orientation using a classification-image like technique. We later used numerically convolved images of different far/near energy and different near additions to study the short term adaptation to pure simultaneous vision using single stimulus detection and scoring tasks...La presbicia es la incapacidad del cristalino para enfocar objetos cercanos. Mientras que las lentes acomodativas son una buena solución para la presbicia, las soluciones más actuales se basan en una corrección aceptable de la visión cercana y lejana simultáneamente. La optimización de estas soluciones pasa por comprender cómo reacciona el sistema a las diferentes correcciones ópticas. El objetivo de esta tesis es el estudio óptico, visual y perceptual de diferentes correcciones a la presbicia como la visión alternante, la mono visión y la visión simultánea, y el estudio del efecto dela adaptación desde el punto de vista perceptual. MétodosSe han medido y corregido las aberraciones oculares mediante un sistema de óptica adaptativa de construcción propia y se han usado imágenes desenfocadas con aberraciones reales con diferentes magnitudes y/u orientaciones para medir el código interno de emborronamiento en los ojos para los diferentes desenfoques y orientaciones mediante métodos de clasificación de imágenes. Posteriormente se han usado imágenes convolucionadas numéricamente con diferentes proporciones en las energías del enfoque cercano o lejano y con diferentes adiciones para estudiar laadaptación a corto plazo en la visión simultánea pura a través de la detección y valoración de estímulos individuales...Fac. de Óptica y OptometríaTRUEunpu

Subjective Dry Eye Symptoms in Pregnant Women–A SPEED Survey

Aim. Multisystemic physiological changes in pregnancy can result in tear film and refractive changes in the eye. We report dry eye prevalence in pregnant women using Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Methods. The SPEED questionnaire was self-administered cross-sectionally to 428 pregnant women (mean age: 26.8±4.4 years) with clinically confirmed pregnancy from two obstetric clinics in Chennai, India. Subjects with predisposing risk factors for dry eye were excluded from the study. Subjects were categorized as normal, moderate, and severe dry eye based on the SPEED score. Results. Among the women, 48.5% of the subjects had symptoms like dryness, grittiness or scratchiness, soreness or irritation, burning or watering, or eye fatigue. About 2.3% had moderate dry eye according to SPEED questionnaire criteria. Eye fatigue was the most reported symptom and was present in 76.4% of women. The symptom frequency score and severity score had a strong and significant correlation (r=0.95, P.05). No significant correlation was found between symptoms of dry eye and gravidity (ρ=−0.006, P>.05) and trimester (ρ=0.38, P>.05). Binary logistic regression showed that only occupational status and systemic condition was significantly associated with dry eye symptoms. Conclusion. About half the pregnant women at the visit reported having one or more dry eye-related symptoms. As per the composite SPEED questionnaire score, dry eye was not prevalent among pregnant women irrespective of their age, gravidity, and the trimester, but we found a majority of pregnant women reported to have experienced dry eye-related symptoms, though tolerable. Awareness about dry eye during pregnancy will improve eye care seeking behaviour in pregnant women

Optical quality and subjective judgments of blur under pure simultaneous vision

ARVO 2013 Annual Meeting, May 5-9, 2013, Washington State Convention CenterPeer reviewe

Effect of adaptation on the Perceptual Score.

<p>Data are presented as a function of defocus in the adapting image: Defocus for Pure Defocus (obtained from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093089#pone-0093089-g004" target="_blank">Figure 4A</a>, solid symbols), and magnitude of defocus in the defocused component (near addition) for Simultaneous Vision (obtained from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093089#pone-0093089-g004" target="_blank">Figure 4B</a>, open symbols). Lines represent linear regressions to the data. Small pale symbols are data after saturation and are not included in the fits. (A) Mean Perceptual Score for test images from 0–1.2 D, as a function of magnitude of defocus in the adapting images. Pure Defocus shows a linear increase (slope 0.57, r = 0.99, p<0.001). Simultaneous Vision shows an initial linear increase (small red open circles, slope = 0.87, r = 0.97, p = 0.13), similar to the Pure Defocus behavior, a maximum at 0.5 D (double circle) and a decrease (large red open circles, slope = −0.3, r = 0.94, p<0.02) for defocus higher than 0.5 D. (B) Maximum shifts in the Perceptual Score (from the Perceptual Score following adaptation to sharp) as a function of defocus in the adapting image, for Pure Defocus (slope = 0.80, r = 0.97, p<0.03) and for Simultaneous Vision (slope = 0.13, r = 0.59, p = 0.2). (C) Defocus in the images that suffered the largest shift in Perceptual Score, as a function of defocus in the adapting image, for Pure Defocus (slope = 0.19, r = 0.945, p<0.06) and for Simultaneous Vision (slope = 1.13, r = 0.94, p<0.005). (D) Relative mean Perceptual Score (mean Perceptual Score of adapting image/mean Perceptual Score of sharp image) as a function of MSSSIM of Pure Defocus and Simultaneous Vision adapting images. There was an initial increase in relative mean Perceptual Score with decrease in the MSSSIM of adapting images.</p

Shift in Natural Perceived Focus after adaptation to Pure Defocus and Simultaneous Vision images.

<p>The test images were series of Pure Defocus images. The adapting images were a gray field, Pure Defocus images, and Simultaneous Vision images with various proportions (25%, 50% or 75%) of sharp and blur (25S/75D, 50S/50D, 75S/25D). (A)–(D) show NPF for individual subjects for the different adapting conditions. (E) NPF shifts (differences with respect to the NPF after adaptation to a sharp image) averaged across subjects. Error bars stand for standard deviations. (F) The change in NPF (MSSSIM) with change in MSSSIM of adapting images. Examples of adapting images are given along with the legend.</p

Perceptual Score of Pure Defocus and Simultaneous Vision 50S/50D image.

<p>Cubic smoothing splines fit of the Perceptual Score responses of (A) Pure Defocus images as a function of defocus in the test image, after adaptation to Pure Defocus images (with defocus ranging from 0 to 1.25 D). (B) Simultaneous Vision images (50% Sharp and 50% Defocus) as a function of the magnitude of defocus (Near addition) in the test image, after adaptation to simultaneous images with different additions (0 to 2.5 D). The crosses on each curve indicate the images producing maximum after effects. It can be noted that 0.5 D adapting image (red line) produces maximum blur adaptation.</p

Estimation of Natural Perceived Focus and its change with adaptation.

<p>An adapting image is presented for 60(500 ms) for subject's response of blur or sharp (2AFC). The next image for test is chosen based on subject's response using a QUEST algorithm. A re-adaptation image is provided between each test image for 3 s. A total of 32 trials were performed and the average of last 10 stimulus values oscillating around the threshold is defined as the Natural Perceived Focus. Test images were Pure Defocus images. The experiment was done in random sequence for 29 adapting conditions (gray field, sharp, Pure Defocus images of various magnitudes of defocus, and Simultaneous Vision images of different sharp/defocus proportions and magnitudes of defocus).</p

Perceptual Score experiment.

<p>Adapting images were presented for 60(500 ms) for subject to score (very sharp to very blurred, in a 6 point scale). Test images were series of 18 Pure Defocus or 19 Simultaneous Vision images presented in a random sequence. The next test image sequence is presented after obtaining subject's Perceptual Score. A re-adaptation image is provided between each test image for 3 s. Subjects adapted to 6 adapting conditions for Pure Defocus (Sharp, 0.25 0.4, 0.6, 1 and 1.2 D) and 7 adapting conditions for simultaneous vision (Sharp, 0.25, 0.5, 1, 1.5, 2 and 2.5 D), in a random order. The Perceptual Score was obtained from the average score of 5 repeated image presentations.</p