AN ARTIFICIAL OCULAR CRYSTALLINE AND PHOTOCHROMIC GLASS Russian patent published in 1998 - IPC

FIELD: medicine, ophthalmology. SUBSTANCE: photochromic material of lenses is additionally characterized by nonreversible slow turning yellow just as natural human crystalline. Such a peculiarity enables to provide more complete correction of vision and retinal protection against photo damage and premature aging. Photochromic glass which provides such peculiarities contains SiO₂, B₂O₃, Al₂O₃, Na₂O, CuCl₂ and AgCl at the following ratio of components, weight%: SiO₂ 58-62, B₂O₃ 18-20, Al₂O₃ 8-12, Na₂O 8-12, CuCl₂ 0.1-0.35, AgCl 0.01-0.6, moreover CuCl₂ and AgCl develop microcrystals of 100-150 size. EFFECT: higher efficiency to protect retina against light damage and increase visual comfort along simultaneous decrease of visual level due to artificial crystalline lenses made of photochromic glass which provides a selective weakening of separate ranges of light radiation, for example, for prophylaxis of senile macular degeneration. 2 cl, 9 cl, 5 dwg