Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Eye prosthesis – Intraocular lens
Patent
1991-04-03
1994-09-13
Isabella, David
Prosthesis (i.e., artificial body members), parts thereof, or ai
Eye prosthesis
Intraocular lens
623 66, A61F 216
Patent
active
053465075
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates generally to ophthalmology and more specifically to an intraocular lens for correction of sight after an operative ablation of the natural crystalline lens, as well as to a polymer composition for making said intraocular lens.
BACKGROUND OF THE INVENTION
Known in the present state of the art are intraocular lenses whose optic lenses are made of polymethylmethacrylate and provide for optical eye correction after removal of the natural crystalline lens.
However, such intraocular lenses fail to protect the retina from being damaged by UV or short-wavelength visible light.
The closest to the herein-proposed intraocular lens are UV-400 lenses, comprising a UV-absorbing optic lens made of a polymethylmethacrylate-based polymer composition and a UV-absorbing substance, such as 2,4-dihydroxybenzophenone.
Such optic lenses protect the retina against damage by light at wavelengths shorter than 380 nm, while such intraocular lenses closely resemble, in the visible light spectrum, natural crystalline lenses of young people aged under the age of 25 and feature the following transmission factor values on a wavelength of: 400 nm, 1.5 percent, 420 nm, 55 percent; 440 nm, 82 percent, while on wavelengths in the range of 460 to 650 nm said factor is within 93 and 95 percent.
However, with the aforesaid light transmission percentage values of the known intraocular lenses an excess amount of light gets into the eye within a range of 400 to 480 nm, which precludes obtaining to the greatest extent of restoration of visual acuity and color perception nor does it enable one to bring to a normal level the protection of the retina against damage with light waves shorter than 480 nm in patients over the age of 25. Besides, the polymer composition used for making such intraocular lenses fails to produce such lenses that would correspond, as for their spectral characteristics, to the natural crystalline lenses of people older than 25.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an intraocular lens and a polymer composition for making the same, which would make it possible to obtain an optic lens that would correspond, as for its spectral characteristics, to the natural crystalline lenses of people over the age of 25 and that, when implanted, would increase the degree of restoration of visual acuity and color perception.
In keeping with the foregoing and further objects, in an intraocular lens, comprising a UV-absorbing optic lens, according to the invention, said optic lens is made of a material featuring the following light transmission spectrum in its visible portion at the following wavelengths: 400 nm, 10 to 27 percent of light transmission; 420 nm, 21 to 37 percent; 440 nm, 37 to 55 percent, 460 nm, 52 to 63 percent; 480 nm, 70 to 78 percent; 500 nm, 85 to 90 percent; 520 to 650 nm, 90 to 95 percent.
Said object is accomplished also due to the fact that in a polymer composition for making said intraocular lens, incorporating polymethylmethacrylate and a UV-absorbing material, according to the invention, said polymer composition comprises, as said UV-absorbing material, 4-alkoxy-2-hydroxybenzophenone or tetraoxybenzophenone, and incorporates additionally a fat-soluble dye, such as, 4-(2,4-dimethylphenylazo)-5-methyl-2-phenyl-1,2,3-triazole, as well as dibutylphthalate as a plasticizer, with the following ratio of the aforesaid ingredients (in mass percent):
Practical application of the proposed intraocular lens having the aforesaid light transmission spectrum of its optical lens provides for transmission of blue light equivalent to its transmission by the natural crystalline lenses of people older than 25, which ensures more complete restoration of visual acuity and color perception, as well as renders the coursing of the postoperative period milder and cuts down its duration. In addition, the proposed intraocular lenses protect the retina against premature ageing and adds to visual comfort.
Use of the proposed polymer composition for maki
REFERENCES:
patent: 4716234 (1987-12-01), Dunks et al.
patent: 4753654 (1988-06-01), Posin et al.
patent: 4822359 (1989-04-01), Tano et al.
Afanasieva Irina I.
Degtev Evgeny I.
Dyachkov Alexandr I.
Fedorov Svyatoslav N.
Fedorovich Irina B.
Brittingham Debra S.
Isabella David
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