Search results for "defocus"
showing 4 items of 14 documents
Visual acuity with computer simulated and lens-induced astigmatism
2014
[EN] The relationship between spherical and astigmatic refractive errors and their associated visual acuity is investigated in this work by means of two different approaches. In the first one, different refractive errors were induced in normal subjects by trial lenses. In the second one, defocused images were simulated numerically by the optical transfer function of a model eye and then judged by the same subjects. The amount of defocus (measured in terms of the modulus of the dioptric power vector) necessary to reduce the visual acuity to 0.1 logMAR and to 0.4 logMAR was computed with each method and then compared. We found that the visual system is clearly more tolerant to lens-induced de…
Comparativa entre lentes intraoculares multifocales: TECNIS Symphony vs AcrySof PanOptix
2016
PROPOSITO: Evaluar el rendimiento visual de la LIOM TECNIS® Symfony y compararla con la LIOM AcrySof® IQ PanOptix™. MÉTODO: Treinta y ocho pacientes (68 ojos) se dividieron en dos grupos: dieciocho pacientes fueron asignados al grupo de Symfony y veinte pacientes al grupo de PanOptix. Los parámetros analizados fueron UDVA, UIVA, UNVA, CDVA, CDIVA, CDNVA, la SC y las curvas de desenfoque monocular ambas en condiciones fotópicas y en un rango de +3 a -5 D en pasos de 0.5 D junto con un cuestionario de calidad de vida. RESULTADOS: Las diferencias de UDVA, CDVA, UIVA, CDIVA no fueron estadísticamente significativas (test Mann-Whitney; p-valor>0.31). Sin embargo, la PanOptix obtuvo mejores resul…
Synthesis of Monodisperse Spherical Nanocrystals
2016
Nanoparticles, small units of matter with dimensions in the range 1-100 nm, exhibit many advantageous size-dependent magnetic, electrical, chemical and optical prop- erties, which are not observed at the microscale or bulk. These properties are extremely sensitive to particle size, and thus the ability to produce monodisperse particles is critical. Due to its ease of use and flexibility, precipitation of nanoparticles from solution is one of the most widely used synthesis methods. The main disadvantage of this method is that the relationship between particle growth and system conditions is not fully understood. In practice, the optimal reaction conditions are usually ascertained empirically…
The defocusing NLS equation : quasi-rational and rational solutions
2022
Quasi-rational solutions to the defocusing nonlinear Schrödinger equation (dNLS) in terms of wronskians and Fredholm determinants of order 2N depending on 2N − 2 real parameters are given. We get families of quasi-rational solutions to the dNLS equation expressed as a quotient of two polynomials of degree N (N + 1) in the variables x and t. We present also rational solutions as a quotient of determinants involving certain particular polynomials.