Hydrogel vs silicone hydrogel lenses: what’s the difference?
Soft contact lenses have come a long way in terms of technology and material. Nowadays, they are either made of hydrogel or silicone hydrogel. But what’s the difference? And is one material better than the other?
What are soft contact lenses?
Contact lenses are classified as ‘hard’ or ‘soft’ according to their elasticity. In simple terms, elasticity describes the material’s ability to hold its shape. Even though hard lenses are longer-lasting, soft lenses tend to be the most popular choice for several reasons.
As their name suggests, soft contacts are pliable and porous and offer greater comfort than hard lenses. They come in two different forms: hydrogels and silicone hydrogels. Both have their benefits, and each offers something different. Here’s a look at how they measure up in terms of comfort and eye health.
Hydrogel lenses
Introduced in the late 1950s, water-loving hydrogels were some of the first lenses made of soft materials instead of hard plastic. The lens’s gel-like consistency adapts to the shape of the eye, resulting in improved comfort and ease of use.
Anyone who wears hydrogels will know that they are stiff when dry but become soft and pliable when hydrated. They have a naturally high water content that allows oxygen to pass through the lens, keeping the eyes white and healthy. This feature makes them ideal for dry and delicate eyes.
Despite the material’s hydrating properties, hydrogel lenses can gradually lose water during wear, causing end-of-day dryness. Additionally, they tend to attract more protein deposits, which can cause discomfort. Rubbing and rinsing reusable lenses, and replacing them to schedule, can help keep deposits in check. Alternatively, you might want to opt for a more frequent replacement pattern, such as daily disposables.
Pros
- Naturally compatible with the human eye
- Suitable for dry and delicate eyes
- Slightly lower price point
Considerations
- Lower oxygen permeability
- Attract more protein deposits
- May experience dryness towards the end of day
Silicone hydrogel lenses
Silicone hydrogels are an advanced type of soft lens that combines enhanced oxygen permeability with water content for optimal comfort and eye health.
The most significant benefit of silicone hydrogels is that they can allow up to five times more oxygen to reach the cornea than regular hydrogel lenses. Without a healthy oxygen supply, the eyes can become dry and itchy, and vision may begin to blur – a condition known as Hypoxia. The enhanced transmissibility of silicone hydrogels keeps the eyes healthy and comfy for longer, making them a great fit for extended wear.
Silicone hydrogels are also slightly firmer than hydrogels, making them easier to handle while still being comfortable on the eye. However, adding silicone to the hydrogel material can increase the accumulation of lipid deposits and reduce the number of water molecules in the lens. Many manufacturers have introduced wetting agents to combat this problem and keep the lens moist for longer.
Some of the latest lens technologies transport oxygen so efficiently that less raw silicone is needed. This is important because it allows more room in the lens for water-loving materials that keep your eyes feeling hydrated.
Pros
- Superior oxygen permeability
- Effortless handling
- Some lenses can be worn continuously for up to 30 nights (speak to your optician first)
Considerations
- Collects more lipid deposits
- Might not be suitable for sensitive eyes
- Slightly higher price
So, which is better – hydrogel or silicone hydrogel?
Neither material is better or worse; it’s just about working with your optician to find the right fit for you and your lifestyle. Both are available in a wide variety of materials, prescriptions and designs to suit almost all vision needs. Browse our full range of lenses here.
