Dual-filter ophthalmic lens to reduce risk of macular degeneration
An improved dual-filter lens for protective eyewear that combines a first filter for blocking essentially 100% of UV light, and second filter for filtering blue light. The first filter may comprise a multi-layered dielectric mirror layer 14 or Rugate filter 50 , and the second filter may comprise dye-impregnated lens layer(s) 16, 18 or Rugate filter 50 . The first filter blocks essentially 100% of UV light, while the second filter establishes an increasing transmission profile that cuts on sharply at approximately 415 nm, and establishes an increasing transmission profile between approximately 415 nm to about 475 nm. The cut-on slope rises approximately 0.15% in transmissivity for every nanometer of increasing wavelength change, with a maximum filtering effect within the 440-465 nm range. These dual filters provide a balanced light transmission profile that reduces harmful light transmission and prevents macular degeneration, cataracts and other ocular injuries, while still preserving visual acuity.
1. A lens comprising:
a polymer material; and
at least two filters incorporated in the polymer material of said lens, said two filters combining to block all UV light and selectively filter blue and violet light pursuant to a sharp cut-on filter that blocks substantially all wavelengths shorter than 415 nm, cuts on at approximately 415 nm, and establishes a transmission profile consisting of a continuously increasing slope from 415 nm to at least 475 nm.
2. The lens according to claim 1 , wherein one of said at least two filters is a first colored dye.
3. The lens according to claim 2 , wherein another of said at least two filters is a Rugate filter.
4. The lens according to claim 2 , wherein another of said at least two filters is a second colored dye.
5. The lens according to claim 2 , wherein said lens material comprises plastic (CR-39).
6. The lens according to claim 5 , wherein 99% of visible blue light is absorbed between 400-475 nm.
7. The lens according to claim 1 , wherein said s is a sunglass lens.
8. The lens according to claim 1 , wherein said lens is a contact lens.
9. The lens according to claim 1 , wherein said lens is an intraocular lens.
10. The lens according to claim 2 , wherein said first colored dye is one from among the group of high-contrast blue-blocking amber-tint and color discriminating grey tint.
11. The lens according to claim 3 , wherein said Rugate filter comprises a bandstop rugate filter for selectively filtering visible blue light between approximately 415 nm to about 475 nm to preserve macular integrity.
12. The lens according to claim 1 , whereby one of said two filters is a band pass filter.
13. The lens according to claim 1 , whereby one of said two filters blocks UV light.
14. The lens according to claim 1 , whereby one of said two filters, filters blue light.
15. The lens according to claim 1 , wherein said transmission profile consists of a continuously increasing slope that rises in transmissivity by approximately 0.15% for every nanometer of increasing wavelength to about 475 nm.
16. The lens according to claim 1 , wherein said lens is an eyeglass lens.