US 6,474,814 B1 · Multifocal ophthalmic lens with induced aperture

Abstract

Multifocal lenses are defined by nonconical aspheric optical surfaces. Various alternative surface shapes provide a central distance vision region surrounded by an optical step. The optical step has rapidly increasing power in the radial direction which creates an induced aperture through which the cortical elements of the vision system are induced to concentrate. The induced aperture results in increased clarity in distance vision. Nonconical aspheric optical surfaces are defined to produce the desired optical power distributions. These surface functions are also provided in form of polynomial series for simplicity of use in computer driven lathes for shaping contact lenses. The invention includes contact lenses, scleral lenses, intraocular lenses, and lenses impressed or surgically shaped within the corneal tissue as well as methods of designing and fitting these lenses.

Claims23

Dependent claims

An ophthalmic lens comprising:

an optical surface of revolution about an apex having an apical distance power, the apex
also having an apical radius of curvature, the surface defined by:
Z(x)=(2·k·(lnP)2)−1·Pk·x+(2·k·(lnP)2)−1·P−k·x+(k·(lnP)2)−1
wherein:
x is a perpendicular distance from the apex in millimeters,
Z(x) defines a sagittal depth at point x,
k is the inverse of the apical radius of curvature in millimeters,
P is an exponential power base,
ln is the natural logarithm function;
and the optical surface forming:
a distance vision region surrounding the apex;
an optical step surrounding the distance vision region;
lens optical power increasing smoothly radially in the distance vision region and optical step to a maximum power in the optical step.

10 more elements

Dependencies are inferred from the claim text.

Multifocal ophthalmic lens with induced aperture

Life of this patent

Multifocal ophthalmic lens with induced aperture

Life of this patent

Abstract

Claims23