Optical lenses with selective transmissivity functions

Abstract

An opthalmic spectacle or contact sharp cut-on orange lens that improves visual acuity and substantially reduces eye damage in a bright sunlit environment. The lenses substantially eliminate ultraviolet radiation and blue light shorter than .[.515.]. .Iadd.520 .Iaddend.nm. The ultraviolet radiation has been implicated as a cause of cateractogenisis. The blue light is implicated in senile macular degenerations, night blindness and snow blindness. The lens is substantially transparent to wavelengths greater than .[.636.]. .Iadd.600 .Iaddend.nm which are most useful for high visual acuity in bright sunlit environment.

Description

TECHNICAL FIELDThis invention relates to lenses and more particularly to lenses having specific transmission properties that increase visual acruity and reduce ultraviolet and blue light hazards.BACKGROUND ARTThere is a growing awareness that wavelengths of sunlight are harmful to the eye. For example, light of the color blue, more more accurately stated, light with wavelengths between 400 nm and .[.515.]. .Iadd.520 .Iaddend.nm are harmful over a long period of time. This is a rather surprising conclusion in view of the widespread presence of blue light, for example in the sky. However, tests have shown that blue light does gradually destroy the supply of visual purple which the retina of the human eye possesses, and can lead to senile macular degeneration, night blindness and snow blindness among other problems.The adverse effects of light having wavelengths in the region between 400-.[.515.]. .Iadd.520 .Iaddend.nm are only recently beginning to be fully recognized and at least par...

AI Technical Summary

Benefits of technology

The lens of the instant invention is made of a plastic material into which is incorporated an organic orange dye 3. This dye has the property of allowing the lens to transmit at least 90% of the visible sunlight with wavelengths longer than .[.636.]. .Iadd.600 .Iaddend.nm and block more than 99% of all sunlight with wavelengths shorter than .[.515.]. .Iadd.520 .Iaddend.nm.

A further object of the invention is to provide a lens that transmits visible light most useful for high visual acuity in brightly sunlit environment.

Problems solved by technology

There is a growing awareness that wavelengths of sunlight are harmful to the eye.

However, tests have shown that blue light does gradually destroy the supply of visual purple which the retina of the human eye possesses, and can lead to senile macular degeneration, night blindness and snow blindness among other problems.

The special lenses which have existed have severely limited properties, because they are made of glass, and additives for the purpose of modifying the transmissivity and must be compatible with the high temperatures used to make the glass.

The range of properties of such substances is very narrow, and does not approach the versatility of organic dyestuffs for this purpose.

However, such dyestuffs are destroyed by the temperatures used in making the glass.

Accordingly, while glass interference coated filters and lenses with special transmissive properties do exist, they are usually quite costly, and fail to provide the advantages of this invention as to low cost, and to versatility and breadth of function and beneficial effect.

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