Compositions and methods for producing silicone hydrogel contact lenses

1. A method for producing a silicone hydrogel contact lens precursor composition, comprising:

mixing a salt, a crosslinking agent, a first hydrophilic monomer, a hydrophobic monomer, a second hydrophilic monomer different than the first hydrophilic monomer, and a third hydrophilic monomer different than either the first hydrophilic monomer or the second hydrophilic monomer, to form a premix composition;

mixing a first silicon containing macromer and a different second silicon containing macromer to form a macromer composition;

contacting the premix composition with an initiator to form a premix/initiator composition; and

contacting the premix/initiator composition with the macromer composition to form a polymerizable monomer-containing composition,

wherein the salt is sodium dioctyl sulfosuccinate, the crosslinking agent is triallyl isocyanurate, the first hydrophilic monomer is N-vinyl-2-pyrrolidone, the hydrophobic monomer is isobornyl methacrylate, the second hydrophilic monomer is 2-hydroxybutyl methacrylate, the third hydrophilic monomer is N-vinyl-N-methylacetamide, the first silicon containing macromer is a polymethylsiloxane methacrylate derivative having a molecular weight of about 1,200, the second silicon containing macromer is a polysiloxanyl dimethacrylate having a molecular weight of about 15,000, and the initiator comprises an ultraviolet photoinitiator.

2. The method of claim 1 , wherein the initiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide.

3. The method of claim 1 , further comprising stirring the polymerizable monomer-containing composition without at least one of (i) disrupting or breaking an exposed surface of the composition and (ii) introducing bubbles into the body of the composition.

4. The method of claim 3 , further comprising adding a tinting agent to the polymerizable monomer-containing composition.

5. The method of claim 4 , wherein the tinting agent comprises particles have an average maximum particle dimension of less than 3 μm.

6. The method of claim 4 , further comprising filtering the polymerizable monomer-containing composition to filter out particles or discontinuous phase which may be present in the composition.

7. The method of claim 6 , wherein the filtering comprises using a filter having pores larger than a maximum size of the tinting agent and being selected from the group consisting of polypropylene filters, glass-polypropylene filters, nylon filters, and combinations thereof.

8. The method of claim 6 , further comprising directing the filtered polymerizable monomer-containing composition into a body of a syringe, the body being made from a material which includes an ultraviolet blocker or filter to reduce exposure of the filtered polymerizable monomer-containing composition to ultraviolet radiation.

9. The method of claim 8 , further comprising a step of degassing the polymerizable monomer-containing composition in the syringe body using a vacuum oven and nitrogen.

10. The method of claim 8 , further comprising placing a piston in the syringe body and placing a cap on an end of the syringe body.

11. The method of claim 10 , further comprising placing the syringe containing the polymerizable monomer-containing composition onto a rack for storage.

12. The method of claim 11 , further comprising storing the polymerizable monomer-containing composition in the syringe at a temperature less than room temperature.

13. The method of claim 12 , wherein the storing is for a period of time selected from the group consisting of about five days at a temperature less than room temperature, and about two days at room temperature.

14. The method of claim 1 , further comprising storing the premix composition for about two weeks without losing chemical properties of the components of the premix composition.