Decoding Contact Lens Materials: Hydrogel vs. Silicone Hydrogel

Soft contact lenses are made from flexible, water-absorbent polymer materials, commonly known as hydrogels, which are widely used in the market today. However, in recent years, with advancements in related technologies, silicone hydrogel materials have made breakthrough developments and are expected to become the mainstream in the future. Today, we will introduce the two types of contact lens materials: hydrogel and silicone hydrogel.

Hydrogel is the most commonly used material in the market. Hydrogel was first invented in the early 1960s and has undergone years of development and improvement, resulting in a wide variety of options. Hydrogel lenses are characterized by their softness and hydrophilicity, making them highly moisturized and initially very comfortable to wear. However, due to their lower oxygen permeability, prolonged wear can lead to dryness in the eyes.

Hydrogel materials mainly include PHEMA (polyhydroxyethyl methacrylate), HEMA (hydroxyethyl methacrylate) mixed materials, and non-HEMA materials. HEMA materials exhibit stable physicochemical properties and good wetting properties. They can also form mixed materials by adding other monomers to increase oxygen permeability and water content, making them more commonly used.

Silicone Hydrogel represents a breakthrough in contact lens research and technology. Silicone has excellent oxygen permeability but poor wetting properties and comfort, which is the opposite of hydrogels. Silicone hydrogel combines the advantages of hydrogels while significantly improving oxygen permeability, no longer solely relying on water content for oxygen permeability, and solving the problem of high-water content lenses evaporating moisture. However, due to its propensity to attract protein deposits, silicone hydrogel lenses are currently only suitable for short-term wear and are priced relatively higher.

As the market acceptance of silicone hydrogel continues to rise, many contact lens retailers highlight it as a selling point. When purchasing, it is important to discern and not be misled.