ONE-WEEK AND ONE-MONTH WATER-GRADIENT CONTACT LENSES Russian patent published in 2022 - IPC G02C7/04 G02B1/04 B29D11/00 

FIELD: ophthalmology.

SUBSTANCE: contact lens is characterized by polyquaternium-1 (“PU”) absorption of approximately 0.40 mcg/lens or less, time before rupture of water film of at least 10 seconds, or a friction rating of 2.0 or lower after 30 cycles of finger wiping. The contact lens contains front and rear surfaces and a layered structural configuration, which contains, in the direction from the front surface to the rear surface: a front outer hydrogel layer, an inner layer of lens material and a rear outer hydrogel layer. The inner layer has the first equilibrium moisture content of about 70 wt.% or less, thicknesses of front and rear outer hydrogel layers range from about 0.25 mcm to about 25 mcm in a fully hydrated state, and the second equilibrium moisture content, which is higher than the first equilibrium moisture content, where front and rear outer hydrogel layers are independently characterized by a water-swelling coefficient of at least 140%.

EFFECT: provision of minimal absorption of polycationic antimicrobials and long-lasting hydrophilicity and wettability of a surface, compatibility with all solutions for lens care, including multipurpose solutions, and high resistance to finger wiping.

64 cl, 6 dwg, 19 tbl