Susana de Marcos

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The wave-front aberration of the human eye was measured for eight subjects using a spatially resolved refractometer (a psychophysical ray-tracing test). The eyes were undilated and presented with accommodative stimuli varying from 0 to -6 diopters. Monochromatic wave-front aberrations tend to increase with increasing levels of accommodation, although there(More)
PURPOSE To investigate the relations between age and the optical aberrations of the whole eye. The eye's optical quality, as measured by the modulation transfer function (MTF), degrades with age, but the MTF does not provide a means to assess the contributions of individual aberrations, such as coma, spherical aberration, and other higher order aberrations(More)
Reflectometric techniques estimate the directionality of the retinal cones by measuring the distribution of light at the pupil plane of light reflected off the bleached retina. The waveguide-scattering model of Marcos et al. [J. Opt. Soc. Am. A 15, 2012 (1998)] predicts that the shape of this intensity distribution is determined by both the waveguide(More)
We performed measurements of refraction (with retinoscopy), axial length (with ultrasound biometry) and ocular aberrations (with a custom-built Hartmann-Shack aberrometer) on seven awake White-Leghorn chicks occluded monolaterally with diffusers for two weeks. Treatment started on the first day after hatching (day 0) and measurements were conducted on(More)
PURPOSE To determine objectively the changes in the ocular aberrations (3rd order and above) induced by myopic LASIK refractive surgery and its impact on image quality. METHODS The ocular aberrations of 22 normal myopic eyes (preoperative refraction ranged from -13 to -2 D) were measured before (2.9 +/- 4.3 weeks) and after (7.7 +/- 3.2 weeks) LASIK(More)
This study investigated differences in geometrical properties and optical aberrations between a group of hyperopes and myopes (age-matched 30.3+/-5.2 and 30.5+/-3.8 years old, respectively, and with similar absolute refractive error 3.0+/-2.0 and -3.3+/-2.0, respectively). Axial length (AL) was measured by means of optical biometry, and corneal apical(More)
PURPOSE To evaluate the optical aberrations induced by LASIK refractive surgery for myopia on the anterior surface of the cornea and the entire optical system of the eye. METHODS Total and corneal aberrations were measured in a group of 14 eyes (preoperative myopia ranging from -2.5 to -13 D) before and after LASIK surgery. Total aberrations were measured(More)
PURPOSE To relate the change of ocular aberrations with the change of visual performance produced by standard laser in situ keratomileusis (LASIK) for myopia. METHODS Aberrations and visual performance were measured before and after surgery in 22 eyes. Total aberrations were measured using a laser ray tracing technique. Corneal aberrations were obtained(More)
We used a fast psychophysical procedure to determine the wave-front aberrations of the human eye in vivo. We measured the angular deviation of light rays entering the eye at different pupillary locations by aligning an image of a point source entering the pupil at different locations to the image of a fixation cross entering the pupil at a fixed location.(More)
PURPOSE The mouse eye is a widely used model for retinal disease and has potential to become a model for myopia. Studies of retinal disease will benefit from imaging the fundus in vivo. Experimental models of myopia often rely on manipulation of the visual experience. In both cases, knowledge of the optical quality of the eye, and in particular, the retinal(More)