Ophthalmic Lens Zwitterionic Coating Deposit Resistance

The patent uses a composite material system consisting of a base polymer (HEMA or silicone hydrogel) combined with zwitterionic monomers (such as carboxybetaine methacrylate or sulfobetaine methacrylate). This composite approach allows the lens to simultaneously achieve high surface hydrophilicity from the zwitterionic groups and deposit resistance from the crosslinked zwitterionic network, resolving the contradiction between these two properties.

The patent changes the chemical parameters of the lens surface by incorporating zwitterionic monomers with both positive and negative charges. This parameter change creates a highly hydrophilic surface that resists protein and lipid deposition through electrostatic repulsion and hydration effects, achieving both improved deposit resistance and maintained surface hydrophilicity.

The patent applies zwitterionic materials locally on the lens surface through surface modification rather than throughout the entire lens bulk. This is achieved by coating the lens with zwitterionic polymers or by incorporating zwitterionic monomers only in the surface layers during manufacturing. This local application maintains the overall physical properties and production efficiency while providing deposit resistance where needed.

The patent performs preliminary surface preparation and modification steps before final lens assembly. By pre-coating lenses with zwitterionic polymers or pre-incorporating zwitterionic monomers into the surface layers during the molding process, the patent ensures deposit resistance is built-in from the start, avoiding rework and improving production yield.

The patent replaces expensive plasma treatment equipment with cost-effective chemical coating methods using zwitterionic polymers or monomers. These materials can be applied through simple dipping, spraying, or in-situ polymerization processes that do not require expensive plasma generation equipment, significantly reducing manufacturing costs while achieving comparable or superior deposit resistance.

The patent substitutes the mechanical/physical plasma treatment process with a chemical approach using zwitterionic materials. Instead of using plasma to modify surface properties, the patent uses chemical polymerization or coating with zwitterionic compounds to achieve deposit resistance, replacing complex plasma equipment with simpler chemical processing systems.

The patent incorporates zwitterionic monomers into the lens material during the initial molding process rather than performing surface modification after lens fabrication. This preliminary incorporation ensures that the zwitterionic network is built-in during the controlled polymerization process, preventing subsequent lens deformation that would occur with post-manufacturing surface treatments.

The patent merges the lens fabrication process with the zwitterionic network formation process. By combining these two processes into a single in-situ polymerization step, the patent ensures that the lens structure and the zwitterionic surface layer are formed simultaneously under controlled conditions, preventing deformation that would result from separate modification steps.

The patent changes the chemical parameters of the surface coating by using zwitterionic polymers or monomers instead of polydopamine. Zwitterionic materials provide high hydrophilicity through their dipolar ionic groups without the brown coloration issue, maintaining both hydrophilicity and optical transmittance by selecting appropriate molecular structures and concentrations.

The patent uses a composite coating system where zwitterionic polymers are combined with optically clear substrates. This composite approach maintains the optical transparency of the base lens while adding the hydrophilic properties of zwitterionic groups, avoiding the coloration problem of polydopamine.