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The purpose of this study was to investigate the relationship between the stiffness of the material comprising the lens and the loss of accommodative amplitude with age. We used a validated mechanical model to determine the changes in the shape of the lens during accommodation and disaccommodation. The relative contribution of lens stiffness to loss of(More)
PURPOSE A change in surface area of the capsular bag and a change in volume of the lens can indicate whether a change in the shape of the lens during accommodation is due to the compressibility or the elasticity of the lens material. METHODS 3D magnetic resonance imaging (MRI) was used to image the complete shape of the lens in a group of five healthy(More)
We present a comparison between measurements of the radius of the anterior and posterior lens surface, which was performed using corrected Scheimpflug imaging and Purkinje imaging in the same group of participants (46 for the anterior lens, and 34 for the posterior lens). Comparisons were also made as a function of accommodation (0 to 7 D) in a subset of 11(More)
Knowledge about geometric properties such as shape and volume and Poisson's ratio of the nucleus can be used in the mechanical and optical modeling of the accommodation process. Therefore, Scheimpflug imaging was used to determine the shape of the human lens nucleus during accommodation in five subjects. To describe the shape of the nucleus, we fitted a(More)
Scheimpflug imaging was used to measure in six meridians the shape of the anterior and posterior cornea of the right eye of 114 subjects, ranging in age from 18 to 65 years. Subsequently, a three-dimensional model of the shape of the whole cornea was reconstructed, from which the coma aberration of the anterior and whole cornea could be calculated. This(More)
A forward ray tracing (FRT) model is presented to determine the exact image projection in a general corneal topography system. Consequently, the skew ray error in Placido-based topography is demonstrated. A quantitative analysis comparing FRT-based algorithms and Placido-based algorithms in reconstructing the front surface of the cornea shows that arc step(More)
PURPOSE To determine the precision and reliability of retinal thickness measurements with an optical coherence tomograph (Stratus OCT 3; Carl Zeiss Meditec, Dublin, CA) and a retinal thickness analyzer (RTA; Talia Technology Ltd., Neve-Ilan, Israel) in foveal, parafoveal, and perifoveal areas. METHODS Three measurements of all areas were performed within(More)
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