Silicone Hydrogel Contact Lenses: A Consumer Guide
Silicone Hydrogel contact lenses were a breath of fresh air for eye care patients when they were brought onto the market in 1999. They are made of high oxygen-permeable plastic that allows up to seven times more oxygen to flow into the cornea than conventional contacts, and they are described as 100 percent more comfortable. Half of all contacts today are made of silicone hydrogel, and many eye care practitioners believe that within the next few years, more patients will be wearing silicone hydrogel lenses than any other lens material.
Types of Silicone Hydrogel Contact Lenses
There are three types of silicone hydrogel lenses available. They are spherical, toric, and bifocal.
The brands of spherical silicone hydrogel lenses currently available, in order of highest oxygen transmissibility to lowest, are:
- Ciba Focus Night & Day; approved for up to thirty day continuous wear. Due to concerns regarding corneal ulcer formation and eye infections, we don’t recommended going beyond 3 nights of extended wear. We also recommended more frequent follow up care for our extended wearers.
- Coopervision Biofinity.
- Ciba 02 Optic and Airoptix Aqua; approved for two week daily wear or up to six nights of extended wear.
- Acuvue Oasys; approved for two week daily wear use or six night extended wear and designed to be wetter than the others.
- Coopervision Avaira; at this time approved only for daily wear and two week replacement.
- Bausch&Lomb Ultra lenses
There are also currently several toric (astigmatism correcting) silicone hydrogel lenses on the market:
- Ciba Airoptix for astigmatism: approved for two to four week replacement and up to six nights of extended wear. Again, we don’t recommended going beyond 3 nights of continuous wear.
- Acuvue Oasys for astigmatism: approved for two weeks of daily wear or up to six nights of extended wear. (Stick to no more than 3 nights continuous wear)
- Bausch&Lomb Ultra for Astigmatism lenses
There is one silicone hydrogel multifocal, the Purevision Multifocal: approved for daily wear or up to thirty days of continuous wear. (Don’t go more than 3 nights continuous wear!) Bausch&Lomb is also about to release its Ultra for Presbyopia lenses.
What’s In Silicone Hydrogel Contacts?
There are different materials in different brands of silicone hydrogel contact lenses. All of them contain silicone hydrogel and oxygen, but some of them include unique materials like Balafilcon A in PureVision, Lotrafilcon A in Night & Day, Lotrafilcon B in O2-OPTIX, and Senofilcon A in Acuvue Oasys. Silicone-based lens materials usually have low surface energy, and as a result have decreased surface wetting.
Benefits vs. Conventional Contacts
The biggest difference patients can perceive is that they are more comfortable than conventional contacts. Also, silicone hydrogel contacts help minimize problems like redness, dryness, swelling of the cornea, and corneal infections. And any infections that do appear tend to be less aggressive and more treatable. Silicone hydrogel lenses allow more oxygen to reach the cornea, which improves eye health.
Other advantages of silicone hydrogel lenses over conventional lenses include more resistance to protein deposits, less drying of the lenses, lower risk of eye infection, easier handling due to the greater rigidity of the material, and high dk levels which remove the risk of conditions like hypoxia to the cornea.
Disadvantages vs. Conventional Contacts
Silicone hydrogel lenses may not be the choice for all patients. These lenses are generally more expensive than non-silicone lenses, so a more price-conscious consumer may not prefer this option. Also, in some patients, the silicone material tends to attract more lipid deposits, which may cause blurry vision and discomfort. Other patients are just not able to adapt well to the more rigid silicone material. So what is beneficial to one patient can have a negative effect on another. It is very important to consult your eye care practitioner before choosing to use silicone hydrogel lenses.
Who Can Wear Silicone Hydrogel Contacts?
Most people benefit from wearing silicone hydrogel lenses rather than conventional soft lenses due to the health advantages, but these lenses are especially useful for the following types of patients:
- Patients with high prescriptions
- Patients whose eyes require more oxygen
- Patients who experience end-of-day discomfort, dryness, or redness with their conventional soft lenses
- Patients who work long hours in low humidity air-conditioning
- Patients who wear their lenses for more than twelve to fourteen hours a day, including overnight wear
Daily Care Instructions
There is a 1 in 2,500 chance of developing an infection if the patient chooses to wear their contacts for a long time. Patients are encouraged to take their lenses out nightly to reduce these chances. Washing your hands before putting in or taking out lenses is also important. Follow these simple guidelines for the daily care of your lenses:
- Rub your lenses when you clean them; soaking alone does not remove debris.
- Clean your lens case daily with hot water. Let it air-dry, rinse with multipurpose solution, and fill the case with a fresh supply. Never top off old solution with new.
- Replace your case monthly.
- Keep your eyes moist. Use rewetting drops or artificial tears several times a day.
Buying Silicone Hydrogel Lenses
Before you purchase this type of lens, it is important to know you will be spending more money regardless of where you buy them. They are new to the market, and like any new product, they are expensive. Of course, we recommended that you get them from our optical. We work with most insurance companies to cover most of the cost of the lenses. We also can get you rebates directly from the contact lens manufacturers to lower the cost even more.
Silicone Hydrogel Allergies
Evidence of silicone allergies during contact lens wear is pretty much non-existent. Doctors use silicone medically for many different purposes, and they say patients usually only encounter problems when they switch lenses. Other eye care practitioners say there are too many other possible culprits like bacteria, tear film proteins, dust, pollen, and chemicals to put the blame solely on the silicone. If you have severe allergies and are concerned about switching to silicone hydrogel lenses, bring the matter up with your doctor.