Silicone Hydrogel Contact Lenses explained
Hydrogel - a soft plastic that contains water - has been used in the manufacture of contacts since the 1970's and was a favourite choice due to its high comfort. With the addition of silicone in 1999, the lenses became more gas permeable, meaning that oxygen could pass through the lens and ensure better health of the cornea underneath.
Silicone hydrogel contact lenses are sometimes wrongly referred to as simply 'Silicon' lenses. This is unfortunate as silicon is a naturally occurring, hard, brittle crystalline solid with a blue-grey metallic lustre that is present in sand and glass and which is the best known semiconductor material in electronic components.
The Silicone used in silicone hydrogel contact lenses on the other hand is a man made synthetic inorganic polymer, it does however contain some silicone along with oxygen and carbon among other elements. Silicone is durable, easy to manufacture and very stable, making it ideal for medical products
Most contact lens types are now available containing silicone hydrogel formulations. The main difference is the length of time they can be worn - some are only suitable for daily wear, while others can be left in for up to 30 days.
What are the benefits of Silicone Hydrogel Contact Lenses?
In a nutshell:
- Silicone hydrogel is a 'next generation' material creating a very soft material that is extremely comfortable to wear and lets the most amount of oxygen to the eyes compared to any other contact lens material. The result - healthy eyes!
- Unlike earlier types of contact lenses, most new wearers need very little time to get used to silicone hydrogel contact lenses, as they can hardly be felt once inserted. Not only are silicone hydrogel contact lenses comfortable but as they allow an increased amount of oxygen to reach your eye they are much healthier for your eyes, The introduction of silicone hydrogel contact lenses means that continuous wear contact lenses are becoming more popular as they are healthier and more comfortable than their predecessors.
Going more indepth on the benefits, by allowing more oxygen to flow into the eyes, silicone hydrogel lenses prevent serious corneal disorders like complications from not getting enough oxygen to the cornea. In fact, silicone hydrogel lenses enable up to five times more oxygen to reach the cornea than regular hydrogel lenses.
In addition to their breathability, silicone hydrogel contacts are far better at retaining water than standard soft lenses. This makes them an ideal choice for people who struggle with conditions like dry eye syndrome.
People who struggle with eye allergies or dry eyes should ask their Optometrist for his/her opinion on silicone hydrogel contacts.
Silicone hydrogel is a soft material that was first launched on the contact lenses market in the late 1990s. Today, contact lenses made from this material are the most popular choice amongst those in need of vision correction and options are available to cater for a variety of vision problems, including myopia and hypermetropia, as well as astigmatism.
Thanks to its enhanced breathability, silicone hydrogel is quickly becoming a favoured material in the soft contact lens industry.
Are Silicone Hydrogel Contact Lenses For You?
Most Optometrists and Ophthalmologists agree that the most obvious benefit of silicone hydrogel lenses is the reduction of hypoxia (low oxygen) -related problems associated with soft lenses made of regular hydrogel materials. This likely has resulted in fewer contact lens related red eyes, discomfort and serious keratitis problems from wearing contacts for extended periods of time.
Due to their increased oxygen transmissibility, silicone hydrogel lenses have enabled many people to comfortably wear contacts for longer hours than they could have with regular hydrogel lenses.
There are many reasons why silicone hydrogel contact lenses might be the best choice for you
- If you have an occupation, where you are likely to be called upon to cover longer hours at short notice - for example a casualty Doctor or a fireman
- If you suffer from dry eyes
- If you need thicker lenses due to a high prescription
- If you work or live in an air conditioned building
Silicone hydrogel materials have also enabled contact lens manufacturers to create a wider variety of lens designs while enabling a healthy amount of oxygen to reach the cornea for safe and comfortable daily or continuous wear.
What Are The Disadvantages Of Silicone Hydrogel Contact Lenses?
Silicone hydrogel lenses have not solved contact lens discomfort problems altogether, and, in fact, some people may experience more lens awareness when wearing silicone hydrogel lenses than when wearing regular hydrogel lenses. Silicone itself is hydrophobic i.e. does not bind well with water, so silicone in a lens can result in being more aware, not less, of their contact lenses.
Manufacturers have overcome this problem by introducing various moisturizing ingredients into the contact lens to increase comfort levels or in the case of Alcon's Dailies Total One, creating a three layer lens, with a silicone core of 33% water content that allows maximum oxygen transmission through the lens, sandwiched between an ultrasoft, high water content (> 80%) surface gel which provides exceptional comfort.
Some studies have shown that silicone hydrogel lenses are more prone to certain types of contact lens deposits, than regular hydrogel lenses, and some contact lens solutions may be less effective on silicone hydrogel lenses than they are on regular soft lenses causing an increased risk of inflammation and corneal infection (microbial keratitis). Once again manufacturers have worked hard to introduce materials to their lenses that minimise surface deposits. For example Crystal Comfort is a silicone lens which incorporates a state of the art surface coating that offers a unique wearing experience so that the lenses have a silky feel all day.
Silicone hydrogel contact lenses can be more expensive than standard hydrogel contact lenses, however the Crystal brand of lenses introduced and affordable daily and monthly silicone contact lens Crystal Air and Crystal Comfort.
If you're interested in buying a pair of Silicone Contact lenses contact lenses, Contactlenses.co.uk can help you find the perfect pair. Our collection includes a variety of items from trusted manufacturers, including Daily silicone lenses like Dailies Total 1 and monthly Silicone lenses like Biofinity.
Author: John Dreyer Optometrist Bsc(Hons), MCOPTOM, DipCLP
Created: 24 Apr 2015, Last modified: 3 Jan 2023