Free-form surface single-focus astigmatism lens for hyperopia correction and design method

Abstract

The invention belongs to the field of ophthalmic optics, and provides a free-form surface single-focus astigmatism lens for hyperopia correction and a design method, the lens is a circular positive lens, the outer surface is a spherical surface or an aspheric surface, and the inner surface is a toroidal surface; the method comprises the following steps: firstly, comprehensively considering a single-eye independent pupil distance, a nose bridge width, a pupil height, a lens edge cutting margin, selected lens frame data and prescription parameters of a lens fitting person to obtain the minimum diameter of the lens; the cutter edge position is set according to the base arc position of the scattered sheet in the toroidal curved surface, so that the cutter edge position is close to the optical center of the lens as far as possible, the center thickness of the lens is reduced to the maximum extent, and the lens subjected to edge cutting and racking obtains the optimal light and thin effect; the inner surface of the lens adopts a toroidal curved surface design, so that off-axis aberration at the periphery of the lens is eliminated, the clear view field at the periphery of the lens is expanded, and the contrast sensitivity of imaging is enhanced; compared with an aspheric lens with an optical design surface on the outer surface, the aspheric lens has the advantage of comfort.

Description

technical field [0001] The invention belongs to the technical field of ophthalmic optics, and in particular relates to a lens for visual correction and a design method. Background technique [0002] The traditional hyperopia astigmatism lens is cast from a mold, the shape is circular, the diameter is fixed, and the edge thickness cannot be less than 1.1mm, so that the center thickness of the lens is thicker; although the aspherical astigmatic lens is designed to be compared to the center thickness of the lens. Spherical lenses have been thinned, but they cannot solve the shortcomings of fixed edge thickness and limited central thickness reduction due to large diameters. Ordinary free-form inner non-astigmatic lenses or customized aspherical astigmatic lenses for workshops can make the edge of the lens thinner by reducing the mirror and cutting edge processing, and the minimum edge thickness can reach 0.5mm, but the circular shape of the lens cannot be formed with the shape o...

AI Technical Summary

Problems solved by technology

[0002] The traditional farsighted astigmatism lens is cast from a mold, the shape is circular, the diameter is fixed, and the thickness of the edge cannot be less than 1.1mm, so that the center thickness of the lens is thicker; although the aspheric astigmatism lens is designed to achieve the center thickness of the lens The spherical lens has been thinned, but it cannot solve the shortcomings of the fixed edge thickness and large diameter, which cause the limited thickness reduction in the center

Ordinary free-form inner astigmatism lenses or aspheric astigmatism lenses customized by the workshop can make the edge of the lens thinner through mirror reduction and knife edge processing, and the minimum edge thickness can reach 0.5mm, but the circular shape of the lens cannot be formed with the shape of the frame Best match, also did not get the best results for light beauty thin

Thick hyperopic lenses not only have a lack of appearance, but also tend to compress the bridge of the nose and produce facial marks, and even cause the glasses to slip off from the normal wearing position, directly affecting visual comfort

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