Aspheric diffraction type contact lens for correcting myopia and presbyopia

Abstract

The invention discloses an aspheric diffraction type contact lens which is used for correcting myopia and presbyopia and has a certain eye regulation function. The diameter of the optical part of the contact lens is 6 mm, the front surface of the contact lens is an axial symmetry type convex aspheric surface, and a diffraction ring used for providing additional diopter is arranged on the front surface. The rear surface of the contact lens is attached to the cornea of people, and the radius of curvature is consistent with that of the anterior corneal surface. After the contact lens is put on, clear imaging can be achieved within the range from medium-range distance to long-range distance (450 mm-infinite distance) and near the read range (240 mm-260 mm) in a field of view which is + / -4 degrees. Furthermore, the contact lens also has the advantages that the extended depth of field is large, and vision stays stable along with pupil change.

Description

technical field [0001] The invention belongs to the field of refraction-diffraction hybrid ophthalmic lenses, and in particular relates to a contact lens with a large depth of field, which can provide the human eye with a continuous and clear range of vision and maintain stable performance when the size of the pupil changes. Background technique [0002] When normal human eyes are in a natural state without adjustment, objects at infinity are just imaged on the retina. When observing a close object, the eye automatically generates an accommodation signal, the ciliary muscle contracts, and the radius of curvature of the lens surface decreases. However, with age, the muscle adjustment ability declines, and the adjustment ability of the lens gradually decreases, thus forming presbyopia, which can only clearly image a specific distance. With the increase of the elderly population in our country, the correction of presbyopia has received more and more attention, and it has also ...

AI Technical Summary

Problems solved by technology

The main defect of this type of design (some of which can be overcome by the new trifocal design) is that the two points in the distance and the near can be seen clearly, and the middle part cannot be seen clearly.

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