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PURPOSE We explored the potential of aberration correction in the human eye by using a new generation of soft contact lenses with aspheric and asymmetric surfaces. METHODS Soft contact lens samples were designed with one asymmetrical surface (front) and one spherical (back) to produce predetermined amounts of desired pure defocus, astigmatism, trefoil,(More)
PURPOSE Outstanding improvements in vision can theoretically be expected using contact lenses that correct monochromatic aberrations of the eye. Imperfections in such correction inherent to contact lenses are lens flexure, translation, rotation, and tear layer effects. The effects of pupil size and accommodation on ocular aberration may cause further(More)
PURPOSE To analyse, retrospectively, the effect of fitting characteristics on comfort of wear and the role that 3D topographic data can play in attaining an optimal lens fit with rigid gas permeable (RGP) contact lenses in normal eyes. METHODS Included were 60 normal myopic eyes (1.00-5.00 D) with astigmatism limited to 2.00 D. Lenses were ordered(More)
Previous studies suggest that certain combinations of coma and astigmatism improve optical quality over astigmatism alone. We tested these theoretical predictions on 20 patients. Visual acuity (VA) was measured under best spherical correction for different conditions: low- and higher order aberrations corrected, in the presence of 0.5 D of induced(More)
Oilbirds (Steatornis caripensis) breed in the total darkness of caves and forage at night on fruits. Common pauraques (Nyctidromus albicollis) are crepuscular and nocturnal foragers on flying insects. We examined if their retinal structure and function can be correlated with their types and periods of activity. Electroretinograms (ERGs) were obtained from(More)
We demonstrate that certain combinations of non-rotationally symmetric aberrations (coma and astigmatism) can improve retinal image quality over the condition with the same amount of astigmatism alone. Simulations of the retinal image quality in terms of Strehl Ratio, and measurements of Visual Acuity under controlled aberrations with adaptive optics were(More)
PURPOSE Astigmatic subjects are adapted to their astigmatism and perceptually recalibrate upon its correction. However, the extent to which prior adaptation to astigmatism affects visual performance, whether this effect is axis dependent, and the time scale of potential changes in visual performance after astigmatism correction are not known. Moreover, the(More)
PURPOSE To test competing hypotheses (Stiles Crawford pupil apodising or superior imaging of high spatial frequencies by the central pupil) for the pupil size independence of subjective refractions in the presence of primary spherical aberration. METHODS Subjective refractions were obtained with a variety of test stimuli (high contrast letters, urban(More)
To what extent can the mammalian visual system be shaped by visual behavior? Here we analyze the shape of the visual fields, the densities and distribution of cells in the retinal ganglion-cell layer and the organization of the visual projections in two species of facultative non-strictly subterranean rodents, Spalacopus cyanus and Ctenomys talarum, aiming(More)
INTRODUCTION There exists an abundant literature on navigation strategies for the visual guidance of goal-directed locomotion. Two main strategies have been documented: the optic flow strategy (OF) and the egocentric direction strategy (ED). OF is assumed to be mainly used when optic flow is densely structured (Harris and Carre, 2001; Wilkie and Wann,(More)