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TitleFoveal vision power errors induced by spectacle lenses designed to correct peripheral refractive errors
Author(s)Barbero, Sergio
Ribeiro, Miguel António Faria
KeywordsRadial Refractive Gradient (RRG) spectacles
Spectacles lens design
Spectacles power errors
Issue date3-May-2018
JournalOphthalmic and Physiological Optics
CitationBarbero S & Faria-Ribeiro M. Foveal vision power errors induced by spectacle lenses designed to correct peripheral refractive errors. Ophthalmic Physiol Opt 2018; 38: 317–325.
Abstract(s)Purpose: Radial Refractive Gradient (RRG) spectacles are lenses specifically designed to minimize peripheral hyperopic defocus typically found in conventional spectacles. Our goals were: (1) to demonstrate a method to design such lenses; and (2) to quantify the exact foveal vision power errors induced by them. Methods: The design procedure was based on a point-by-point sequential surface construction algorithm that designs a front aspheric surface (back surface is spherical) to achieve a given overall tangential focal length of the lens. A peripheral refraction model was built based on average peripheral refractive errors from a set of eyes. We designed four negative lenses with optical powers: 2.5, 5.0, 7.5 and 10.0 D, so that the tangential focal length of the lens matches the retinal conjugate surface. Results: The lenses induce very small sagittal power errors in a wide range of offaxis field angles (30°), solving the problem of peripheral hyperopic defocus. However, such designs introduce non-negligible mean power errors (above 0.25 D from 7°, 6.8°, 7.1° and 7.8° for the 2.5, 5.0, 7.5 and 10.0 D lenses, respectively) for foveal vision in a rotating eye. Conclusion: Our results show the unavoidable errors introduced by RRG spectacles when used for dynamic foveal vision. The described method offers valuable information towards determining the best trade-off between controlling power errors for peripheral and foveal vision.
Publisher version
AccessOpen access
Appears in Collections:CDF - OCV - Artigos/Papers (with refereeing)

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