Contact lens for correction of irregular astigmatism

Abstract

Disclosed is an implementation of new technology for effectively providing a contact lens capable of achieving satisfactory corrective effects even with respect to irregular astigmatism (residual irregular astigmatism) caused by a conical cornea and so forth, which could not be corrected with conventional eye glasses or contact lens, wherein the contact lens is not dependent on being made to order for each wearer but is industrially mass-producible by means of a practical and novel structure. A contact lens for correction of irregular astigmatism is disclosed wherein a positive correction area (27) is provided on one side of a special radial line (30) and a negative correction area (28) is provided on another side while in any of the correction areas (27, 28) a lens power is configured so that an absolute value becomes progressively larger from an outer peripheral edge part towards a central portion.

Description

technical field [0001] The present invention relates to contact lenses for correcting irregular astigmatism caused by keratoconus and the like. Background technique [0002] In the past, prescription lenses and contact lenses were used for refractive errors of the eye. These eyeglasses and contact lenses are prescribed by correcting the optical properties of the wearer's eyes to provide good vision. In particular, using contact lenses, various types of research are advancing to achieve better vision, and many structures have been proposed since the past, for example, with the aim of improving positional stability in the circumferential direction, such as when correcting astigmatism or hyperopia, for example performance, achieve bifocal optical properties when correcting hyperopia, improve comfort when worn, etc. One of the inventors of the present invention also discloses in Japanese Patent No. 3870219 (Patent Document 1) a contact lens equipped with a series of combinatio...

AI Technical Summary

Problems solved by technology

Moreover, even if the optical characteristics to correct irregular astigmatism for each individual with high precision can be given together with the positioning mechanism that specifies the circumferential stop position in the wearing state, the visual quality is not stable because it is impossible to completely control the contact lens displacement

Because of this, in the end, as in the past, it is not only impossible to avoid processing technology problems and manufacturing cost problems, but it is also difficult to achieve satisfactory visual quality. There are still such problems, and it is still impossible to achieve an effective correction effect on residual irregular astigmatism. contact lenses

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