Method for producing photochromic contact lenses
US11542353B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 2020 |
| Grant date | Jan 3, 2023 |
| Priority date | — |
| Expiry date | Jul 17, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/043
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The invention provides a method for producing photochromic silicone hydrogel (SiHy) contact lenses based on thermal cast-molding technology in a relatively efficient and consistent manner. The method is characterized by selecting a high radical-reactive hydrophilic acrylic monomer while eliminating any low radical-reactive hydrophilic N-vinyl amide monomer in a lens formulation (polymerizable composition), by selecting a weight ratio of low-radical-reactive hydrophilic N-vinyl amide monomer to a high radical-reactive hydrophilic acrylic monomer in a lens formulation if the low radical-reactive hydrophilic N-vinyl amide monomer is needed, and/or by using a relatively high temperature thermal initiator in a lens formulation, to control the lens properties (e.g., water content, elastic modulus, etc.) and lens processability (capability of dry-delensing from molds) of thermally cast-molded SiHy contact lenses while minimizing loss in photochromic ability of resultant SiHy contact lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.