ASYMMETRIC DISPLACEABLE CONTACT LENS Russian patent published in 2015 - IPC G02C7/04 

FIELD: physics, optics.

SUBSTANCE: displaceable presbyopic contact lens comprises an optical zone, a lens portion surrounding the optical zone, a conical portion surrounding the lens portion from the outside to the edge of the contact lens and pseudotruncation which is asymmetrical about the vertical meridian. The point where the optical zone borders with the lens portion is an optical-lens boundary. The point where the lens portion borders with the conical part is a lens boundary of the edges of the cone. The structure of the lens surface is defined by the equation: T₃=T₁+(T₂-T₁)*(Sin ((P₃-P₁)/(P₂-P₁) *90))ⁿ , where P₁ is the distance from the centre of the lens to the optical-lens boundary, T₁ is the thickness of the optical lens boundary, P₂ is the distance from the centre of the lens to the lens boundary of the edges of the cone, T₂ is the thickness of the lens boundary, P₃is an arbitrary point on the contact lens located between and including P₁ and P₂, and T₃ is the thickness defined at point P₃.

EFFECT: facilitating displacement of the lens owing to its support on the lower lid and more comfort when wearing the lens.

6 cl, 7 dwg