Soft gas permeable contact lens having improved clinical performance

• US 5,712,327 A
• Filed: 06/16/1992
• Issued: 01/27/1998
• Est. Priority Date: 01/07/1987
• Status: Expired due to Term

• Current Assignee: Rembrandt Vision Technologies LP (Rembrandt IP Management, LLC)
• Original Assignee: Mei-Zyh Chang, Sing-Hsiung Chang
• Inventors: Chang, Mei-Zyh, Chang, Sing-Hsiung
• Primary Examiner(s): Lilling, Herbert J.
• Application Number:
  US07/899,217
• Time in Patent Office: 2,051 Days
• Field of Search: 523/106, 523/107, 264/2.6, 264/1.1, 351/160 R, 351/160 H, 427/2, 427/487, 427/496, 427/508, 427/515, 427/2.24, 524/424, 526/279, 526/282, 526/264, 522/99, 525/326.5, 525/342, 525/477
• US Class Current: 523/107
• CPC Class Codes: C08L 43/04 Homopolymers or copolymers of monomers containing silicon
• CPC Class Codes: G02B 1/043 Contact lenses

Abstract

A hydrophilic soft gas permeable contact lens having substantially improved clinical performance by the provision of a sufficient higher proportion of hydroxy acrylic units to silicon units in the lens surface layer, as compared to that existing in the lens core, by the surface treatment of the lens, such as by reacting of the lens surface with polyols and base or acid or by radiation treatment of the base lens to graft, deposit or coat thereon hydroxy acrylic units.

Claims

1. A hydrophilic soft gas permeable contact lens comprised of a polymerization product of a composition comprising a polymerizable vinylic siloxane monomer and a hydrophilic vinylic monomer, and having at least 25% water by weight and characterized by high oxygen permeability, softness, rebound elasticity and a high degree of clinical performance, said lens comprising a hydrophilic lens body and a tear-wettable surface layer integral therewith, said lens body being comprised of said polymerization product and said tear-wettable surface layer being comprised of polymeric material containing hydroxy acrylic monomer units, and wherein the proportion of hydroxy acrylic monomer units to silicon units in said tear-wettable surface layer is greater than that of said lens body.

2. A contact lens according to claim 1 wherein said hydroxy acrylic monomer units are selected from the group consisting of hydroxyalkyl acrylate, hydroxyalkyl methacrylate, acrylic acid, methacrylic acid, and combinations thereof.

3. A contact lens according to claim 2 wherein said hydroxy acrylic monomer units are 2-hydroxyethyl methacrylate.

4. A contact lens according to claim 2 wherein said hydroxy acrylic monomer units are methacrylic acid.

5. A contact lens according to claim 1 wherein said hydroxy acrylic monomer units are itaconic acid.

6. A contact lens according to claim 1 wherein said polymerizable vinylic siloxane monomer is γ

-tris(trimethylsiloxy)silylpropyl methacrylate, and wherein said hydrophilic vinylic monomer is N,N-dimethylacrylamide.

7. A method for making a hydrophilic soft gas permeable contact lens having improved clinical performance, said method comprising the steps of:

(a) forming a hydrophilic soft gas permeable contact lens body having at least 25% water by weight and comprised of a polymerization product of a composition comprising a polymerizable vinylic siloxane monomer and a hydrophilic vinylic monomer; and

(b) reacting said lens body with a member selected from the group consisting of (i) a polyol of the formula R₁ (OH)_n, wherein R₁ is a substituted or unsubstituted alkyl and n is an integer of at least 2, and (ii) hydroxy acrylic monomer, to provide on said lens body a surrounding tear-wettable surface layer integral therewith, said surface layer being comprised of polymeric material containing hydroacrylic monomer units, and wherein said tear-wettable surface layer has a proportion of hydroxy acrylic monomer units to silicon units greater than that of said lens body.

8. A method according to claim 7 wherein said hydroxy acrylic monomer units are selected from the group consisting of hydroxyalkyl acrylate, hydroxyalkyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, and combinations thereof.

9. A method according to claim 7 wherein said polyol is selected from the group consisting of ethylene glycol, glycerine and mixtures thereof.

10. A method according to claim 7 wherein step (b) comprises reacting hydroxy acrylic monomer to said lens body by radiation-initiated reaction, to form said surface layer.

11. A method according to claim 10 wherein said radiation-initiated reaction utilizes electromagnetic radiation.

12. A method according to claim 10 wherein said radiation-initiated reaction utilizes γ

-ray or UV radiation.

13. A method according to claim 10 wherein said radiation-initiated reaction utilizes radiation selected from the group consisting of electron beam, electrical discharge and radio frequency.

14. A method according to claim 7 wherein said polymerizable vinylic siloxane monomer is γ

-tris(trimethylsiloxy)silylpropyl methacrylate and wherein said hydrophilic vinylic monomer is N,N-dimethylacrylamide.