Method of the manufacture of an implantable intraocular planar/convex, biconvex, planar/convex or convex/concave lens, an open mold used for the execution of this method, and a lens made using this method
The invention is related to a method of the manufacture of an implantable lens from a liquid polymer precursor in an open mold, during which the liquid polymer precursor in metered into the open mold in a such measured amount, that comes into contact with a functional shaping inner surface of the open mold, which is located under a peripheral circular sharp edge of the stationary open mold or which reaches up to this peripheral circular sharp edge, at which point the open mold, which contains the liquid polymer precursor, is rotated around it's vertical axis at a speed, at which the edge of the surface of the liquid polymer precursor reaches the peripheral circular sharp edge of the open mold, after which the liquid polymer precursor is exposed to conditions, under which it transforms itself into a state of a clear solid polymer by polymerization and/or cross-linking, until such time, at which the stated transition is attained, and then the implantable intraocular lens is removed from the open mold. The invention also includes the open mold used for the implementation of the stated method and the lens produced in this way.
1. A device for manufacturing an implantable planar/convex, biconvex, planar/concave or convex/concave lens made from a liquid polymer precursor, comprising:
a one-piece, open mold, the mold comprising an open concave cavity, delineated by a functional shaping inner surface being unwettable or incompletely wettable by a liquid precursor and ending by a peripheral sharp edge having the shape of a circle which lies in the plane perpendicular to the vertical axis of the open concave cavity and has a diameter of 5 to 10 mm;
wherein the radius of curvature of the open concave cavity increases from the lowest value in the proximity of the vertical axis of the open concave cavity in the direction towards the peripheral sharp edge of the open concave cavity; and
wherein the open concave cavity passes in the top part of the open mold over an intermediate circular edge having the shape of a circle lying in the plane parallel to the plane of the peripheral sharp edge into a transitional open cylindrical or frustum-of-a-cone cavity delineated between the peripheral sharp edge and the intermediate circular edge, wherein the transitional open cylinder or frustrum-of-a-cone cavity defines a planar surface at an angle α2 less than or equal to 90°; and
a means for rotating the mold.
2. An open mold according to claim 1 , wherein the functional shaping inner surface of the open concave cavity has the shape defined by the rotation of a part of a conical section along the vertical axis of the open concave cavity.
3. An open mold according to claim 2 , wherein the conical section is defined by the equation Y=−a+(a/b)·(b2+X 2 ) 0.5 , in which a=Rc·(1+h) 2 and b=Rc·(1+h), where Rc is the center curvature radius and h is parameter defining asphericity, which is selected from an interval between −1 and +infinity.
4. An open mold according to claim 3 , wherein the parameter h defining the asphericity is chosen from an interval from −0.75 to +1.
5. An open mold according to claim 3 , wherein the center curvature radius Rc is chosen from an interval from 2 to 20 mm.
6. An open mold according to claim 1 , wherein the peripheral sharp edge has the shape of a circle with diameter from 7 to 9 mm.
7. An open mold according to claim 1 , wherein the height of the transitional open cylindrical or frustum-of-a-cone cavity is equal to 0.01 to 0.2 mm.
8. An open mold according to claim 1 , wherein the combined volume of the open concave cavity and the transitional open cylindrical or frustum-of-a-cone cavity equals 15 to 175 μl.
9. An open mold according to claim 1 , wherein it is formed from a polymeric plastic which is not wettable, or is only incompletely wettable by the liquid polymer precursor.