There are a variety of contact lenses out there, all designed to suit different needs. One common option are soft contact lenses, which have typically been made from a flexible material, called hydrogel, that allows oxygen to pass through to the cornea. This makes it easy for first-time users to adjust to these lenses, allowing them to wear them comfortably for an extended amount of time.
There is a newer, more advanced type of material for soft lenses, called silicone hydrogel. This material allows even more oxygen to enter the eye than standard hydrogel lenses, which can contribute significantly to your overall day-to-day comfort.
What is silicone hydrogel made of?
Silicone hydrogel contact lenses are made from a modern type of soft lens material, silicone, which is a plastic with a gel-like consistency that makes it extremely flexible.1 There are more than a dozen different types of silicone hydrogel materials available at present, including senofilcon, galyfilcon, efrofilcon, and delefilcon. Each material has a varying amount of water content and other properties, meaning that they vary in their comfort and adaptability.1,2
What are the benefits of silicone hydrogel over standard hydrogel?
The biggest advantage of using silicone hydrogel contact lenses over regular hydrogel lenses is increased oxygen permeability.3 Allowing oxygen through to the eye is important, as a reduced oxygen supply to the cornea can result in symptoms such as dryness, redness, blurred vision, discomfort, and corneal swelling.3 It can also increase the likelihood of infections, and can make you notice the lens in your eye more.3,4
Studies have shown that wearers of silicone hydrogel lenses report significantly higher comfort, both during the day and at the end of the day, compared to conventional hydrogel lenses.3 Because of the increased oxygen permeability, silicone hydrogel contact lenses are especially useful for people who get dry eyes, need to wear thicker lenses because of higher prescriptions, experience end-of-day discomfort and dryness, work in dry air-conditioned environments, or wear contact lenses for more than 12 hours a day.5
Another benefit of silicone hydrogel is that it attracts fewer protein deposits.1 Proteins that are naturally present in the tear film (a thin fluid layer on the eye) can become deposited on the contact lens surface, which can lead to eye discomfort and the need to replace lenses more frequently.
Can you be allergic to silicone hydrogel?
An allergy to silicone hydrogel materials is quite rare.4 Often, the culprit for allergic symptoms such as redness, itching, watery eyes, and discomfort is something other than the contact lens material, such as bacteria, pollen, dust, or chemicals.4 Some people may even experience problems when they switch lenses. If you’re concerned about an allergic reaction to silicone hydrogel, or any contact lenses, your best option is to head to your optometrist.
What are the disadvantages of silicone hydrogel contacts?
Silicone hydrogel contact lenses may not be suitable for everyone. They are generally more expensive than conventional hydrogel soft contact lenses, which can make them less accessible if you’re on a budget.
What’s more, some studies have shown that silicone hydrogel materials may be incompatible with certain lens solutions, leading to an increased incidence of corneal infection and inflammation (microbial keratitis).6
Is there a difference in comfort between daily use and extended wear silicone hydrogel contact lenses?
Single-use daily disposables are less likely to collect deposits (which can cause slight discomfort), as there isn’t enough time before they’re exchanged for a fresh pair. Extended wear silicone hydrogel contact lenses, on the other hand, are used every day for two weeks or one month, increasing the chances of a deposit build up.
As such, people with sensitive or dry eyes may benefit from silicone hydrogel daily contact lenses because both the material and the replacement schedule prevent deposits from gathering, which can lead to discomfort in the eye.
- CooperVision. (no date). Silicone Hydrogels: What’s The Difference? [Online]. Available at: https://coopervision.com/about-contacts/silicone-hydrogel-contact-lenses [Accessed 17 October 2019].
- Tighe BJ. A decade of silicone hydrogel development: surface properties, mechanical properties, and ocular compatibility. Eye Contact Lens. 2013 Jan;39(1):4–12. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pubmed/23292050 [Accessed 17October 2019].
- JNJVisionCare. (no date). Daily Decisions: Silicone Hydrogel or Hydrogel? [Online]. Available at: https://www.jnjvisioncare.co.uk/sites/default/files/public/uk/tvci/optician_daily_decisions_sih_or_hydrogel.1.7.11.pdf [Accessed 17 October 2019].
- Eye Health Web. (no date). Silicone Hydrogel Contact Lenses: A Consumer Guide. [Online]. Available at: https://www.eyehealthweb.com/silicone-hydrogel-contact-lenses/ [Accessed 17 October 2019].
- CooperVision. (no date). The Benefitsof Silicone Hydrogel Daily Disposable Lenses. [Online]. Available at: https://coopervision.com.sg/practitioner/fitting-tips-and-tools/benefits-of-silicone-hydrogel-lenses [Accessed 17 October 2019].
- Robertson DM. The effects of silicone hydrogel lens wear on the corneal epithelium and risk for microbial keratitis. Eye Contact Lens. 2013;39(1):67–72. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3587121/ [Accessed 17October 2019].