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Ophthalmic lenses
Published in Pablo Artal, Handbook of Visual Optics, 2017
where nd, nf, and nc are the refractive indices for yellow, blue, and red light. This number represents the chromatic dispersion of the material. The larger the Abbe number is, the smaller the chromatic dispersion. A large chromatic dispersion introduces chromatic aberration in the image. In this sense, a large Abbe number is desirable.
Impact of Lens Material on Objective Refraction in Eyes with Trifocal Diffractive Intraocular Lenses
Published in Current Eye Research, 2022
Nuria Garzón, Francisco Poyales, María García-Montero, Fidel Vega, María Sagrario Millán, César Albarrán-Diego
Diffraction and refraction induce chromatic aberration by dividing light in its colour spectrum in the opposite way. A refractive element works by refracting short-wavelength light more (blue spectrum), and long-wavelength light less (red spectrum). With diffraction the opposite happens, so that a diffractive element acts as if it had more refractive power for long-wavelength light than for short-wavelength light. This behaviour is the key for chromatic aberration correction solutions combining refractive and diffractive elements. Given that POD F and POD F-GF have the same diffractive pattern but different materials with different Abbe number, a different chromatic aberration behaviour can be expected.37,38 Since AR works with infrared light to not stimulate accommodation, different AR reliability could be expected for POD F and POD F-GF. The same can be suspected with aberration ObjRx measurement methods using a different wavelength.
Comparison of visual performance between two aspheric monofocal intraocular lens models
Published in Clinical and Experimental Optometry, 2023
Francisco Poyales, Nuria Garzón, Laura Rico, Ying Zhou, María S Millán, Fidel Vega
The system used by Millán et al.15 was used for longitudinal chromatic aberration (LCA) measurements. This system relies on the Scheiner disc, with double pinhole, and the sequential illumination with two monochromatic light sources whose wavelengths are 455 nm and 625 nm.