Method of making ophthalmic devices and components thereof from hydrophobic acrylic (HA) polymers with reduced or eliminated glistenings
This invention relates to the fields of polymer chemistry, materials science and ophthalmology. More particularly it relates to optical components and method(s) of preparing same from hydrophobic acrylic (HA) monomer(s) that exhibit reduced or eliminated glistenings when implanted in a patient's eye. The method of this invention uses a mixture of one or more low temperature initiators (LTI) combined with one or more high temperature initiators (HTI), to polymerize one or more HA monomers to produce an optical HA polymer which, when used to manufacture an optical component and implanted as with an intraocular lens (IOL), exhibit reduced glistenings to the patient.
1. A method for making a hydrophobic acrylic (HA) optical component having reduced glistenings comprising the steps of:
providing a monomer or a mixture of monomers which, when polymerized produce a hydrophobic acrylic polymer which can be formed into an optical component of an ophthalmic device;
providing two or more polymerization initiators, one of the initiators being a low temperature initiator (LTI), the other polymerization initiator being a high temperature initiator (HTI);
combining the initiators with the hydrophobic acrylic monomer(s) to create a reaction mixture;
reacting the reaction mixture by the steps of:
to produce a hydrophobic acrylic polymer; and
exposing the reaction mixture to a temperature of 50° C. for 1 to 4 hours;
exposing the reaction mixture to a temperature of 60° C. for a time period of 1 to 6 hours; and
exposing the reaction mixture to a temperature of 100° C. for from about 1 to 12 hours to produce a hydrophobic acrylic polymer; and
forming the polymer into the optical component.
2. A method according to claim 1 wherein the optical component is the optic of an intraocular lens.
3. A method according to claim 1 wherein the LTI has a 10 hour half-life temperature of 61° C. or lower.
4. A method according to claim 1 wherein the HTI has a 10 hour half-life temperature of 62° C. or higher.
5. A method according to claim 1 wherein the 10 hour half-life temperature difference below the LTI and the HTI is at least 5° C.
6. A method according to claim 1 wherein the 10 hour half-life temperature difference below the LTI and the HTI is at least 15° C.
7. A method according to claim 1 wherein the mixture of polymerization initiators is present in the range of about 0.05 to about 2.0 weight percent of the reaction mixture.
8. A method according to claim 1 wherein the reaction mixture is combined with about 0.1 to about 1.0 weight percent UV blocking agent before being reacted.
9. A method according to claim 1 wherein the reaction mixture is combined with about 0.1 to about 1.0 weight percent blue light blocking chromophore before being reacted.
10. A method according to claim 1 wherein the mixture of initiators comprises about 10 to about 90 weight percent LTI and concomitantly about 90 to about 10 weight percent HTI.
11. A method according to claim 1 wherein the LTI is di(n-propyl) peroxydicarbonate.
12. A method according to claim 1 wherein the HTI is 2.2′-azobis(isobutyronitrile).
13. A method according to claim 1 wherein the LTI is di(n-propyl) peroxydicarbonate and the HTI is 2.2′-azobis(isobutyronitrile).