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A progressive multifocal ophthalmic lens with optimized center of curvature and preparation method thereof
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A progressive multi-focus, center of curvature technology, applied in glasses/goggles, optical components, instruments, etc., can solve problems such as unfavorable astigmatism, and achieve the effect of improving optical performance and wearing comfort.
Active Publication Date: 2019-05-10
SUZHOU UNIV OF SCI & TECH
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The center of curvature of each point on the progressive multifocal surface also has a great influence on the astigmatism of the progressive multifocal ophthalmic lens. In the above technical solution, although the x coordinate ξ and the z coordinate ζ of the curvature center are calculated, the curvature center The y coordinate η of is forced to be set to zero, which is not conducive to reducing unnecessary astigmatism
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Embodiment 1
[0116] In this embodiment, an internal progressive multifocal lens with an addition power of 2 diopters is designed according to the needs of the spectacle wearer. The refractive index of the lens material is 1.532, and the lens diameter The designed focal power of the inner surface distance zone Φ PA It is -4 diopters; the focal power of the near zone is Φ PB is -2 diopters.
[0117] According to the contour line design method disclosed in Chinese invention CN103246080A, the contour line distribution u(x, y) is obtained, the values of h, L, m, and l are taken as 30, 12, 9 and 6 respectively, and the grid point step size is 3mm. Substituting u(x, y) into formula (1) and formula (4) to obtain R, ξ, η, ζ, wherein η=0, substituting R, ξ, η, ζ into formula (3) to obtain progressive multifocal ophthalmic The initial sagittal height of the lens.
[0118] Using the central difference method to find the first and second partial derivatives of z: Substitute and solve the bina...
Embodiment 2
[0125] The initially designed lenses in this example are exactly the same as those in Example 1. Substituting u (x, y) into formula (1) and formula (4) to obtain ζ, R, ξ, η, wherein η=0, substituting ζ, R, ξ, η into formula (3) to obtain progressive multifocal ophthalmic The initial sagittal height z of the lens.
[0126] The optimization function (2) is used for optimization.
[0127] The central difference method is used to calculate the first and second partial derivatives and third partial derivatives of the initial design R, ζ and ξ, respectively, to obtain
[0128] Substituting the above quantities into formula (16) to obtain the expression F of the square of the principal curvature difference (2) , the F (2) Substitute into formula (28) to get about c 1 、c 2 system of binary nonlinear equations. set c 1 、c 2 Initially they are all zero, and the root of the nonlinear equation system formula (28) is c 10 = 0.0813 and c 20 =-0.0007, after trying, take the adj...
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Abstract
The invention discloses a curvature center optimized progressive multifocal spectacle lens and a preparation method thereof. Two optimization functions of the curvature center y coordinate eta are established to optimize eta in the curvature center (xi, eta, zeta) of a progressive multifocal spectacle lens surface rise expression in the prior art so as to obtain an optimized lens surface rise, andthen the lens is processed. The result of comparison before and after lens surface rise optimization indicates that the two optimization functions provided by the invention can significantly improvethe optical performance of the progressive multifocal spectacle lens and improve the wearing comfort of lens wearers.
Description
technical field [0001] The invention relates to a progressive multifocal ophthalmic lens, in particular to a progressive multifocal ophthalmic lens with an optimized center of curvature and a preparation method thereof. Background technique [0002] Progressive multifocal ophthalmic lenses can meet the needs of distance vision and near vision at the same time, and avoid the defects of bifocal lenses such as visual breakage when switching from distance vision to near vision. See attached figure 1 , the surface of the progressive multifocal ophthalmic lens is divided into a distance zone 1, a gradient channel (or intermediate transition zone) 2, a near zone (reading zone) 3 and an astigmatism zone 4; figure 1 Among them, A is the reference point of the far zone, and B is the reference point of the near zone; the far zone, the near zone and the gradient channel are collectively referred to as the effective vision zone. [0003] Since the pupil of the human eye is small, with ...
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