Hydrogel vs. Silicone Hydrogel Lenses
Hydrogel and silicone hydrogel are the materials used to make most soft contact lenses available today. They are plastics that are hard when dry but absorb water and become soft and gel-like when hydrated.
Hydrogel and silicone hydrogel are both thin and flexible. These materials allow oxygen to reach your cornea so your contacts will be comfortable to wear.
What Are Hydrogel Contact Lenses?
In the 1970s, eye doctors started to prescribe hydrogel contact lenses more often than other types of contacts. They liked hydrogel because it fit the shape of the eye and was comfortable and easy for patients to use.
Pros and Cons of Hydrogel Contact Lenses
If you want to try soft contact lenses, including disposable lenses, you’ll probably get hydrogel contact lenses. The majority of soft contacts are made from this material.
Hydrogel is also a good choice if you have dry and/or sensitive eyes because they’re biocompatible with your eyes. This means hydrogel is safe for you to use, and you won’t have a negative reaction when you wear contacts made from this material.
As with most medical devices — particularly those that come in direct contact with your eyes — there are pros and cons of hydrogel contacts.
A few reasons hydrogel contact lenses could be right for you include:
- They hold a lot of water. Hydrogel contact lenses have a lot of water to keep your eyes moist. This makes them the best option for people who have sensitive eyes.
- They can be used by people with dry eye syndrome. Hydrogel lenses are the only soft contact lenses approved by the U.S. Food and Drug Administration to be marketed as a contact lens for dry eyes.
- Hydrogel contacts are a top choice among eye doctors. Eye doctors still prescribe soft contacts made from hydrogel today because they’re comfortable, easy to use and durable.
All contact lenses can increase your risk of serious eye infections such as keratitis, which is inflammation of the cornea — the clear front surface of the eye. Keratitis and other infections can lead to vision loss or blindness.
Disadvantages of hydrogel lenses include:
- They can’t be worn for long periods of time. The water in hydrogel contact lenses gradually evaporates, making them uncomfortable to wear for long periods.
- They only let some oxygen reach your eyes. Your eyes need oxygen to be healthy. Hydrogel lenses block most oxygen from passing through the lens and getting to your eyes when you’re wearing them.
- They can lead to oxygen deprivation syndrome. If you wear your soft contacts for too long, you can get oxygen deprivation syndrome. When your contact lens blocks oxygen from getting to your cornea, your cornea tries to get oxygen by increasing blood flow to your eye. When this happens, new blood vessels develop in your eyes that often lead to swelling and changes in vision.
What Are Silicone Hydrogel Contact Lenses?
Silicone hydrogel is the next generation of hydrogel. Silicone added to regular hydrogel allows up to five times more oxygen to pass through the lens and reach the cornea. Your eyes can get more oxygen from silicone hydrogel lenses even if you wear them while you sleep.
Pros and Cons of Silicone Hydrogel Contact Lenses
If you want contacts that you don’t have to change every day, silicone hydrogel lenses may be right for you. The combination of silicone and hydrogel allows more oxygen to enter the cornea. This makes silicone hydrogel contacts safer and more comfortable to wear for long periods of time than regular hydrogel lenses.
Like hydrogel lenses, there are pros and cons to wearing silicone hydrogel contacts.
Other benefits include:
- They could reduce the risk of painful eye conditions. A lack of oxygen to the cornea can lead to problems, including red eyes, blurred vision, corneal swelling and eye discomfort. It can also increase the chance of getting an eye infection. More oxygen reaching the cornea can help eyes stay healthy.
- They can prevent oxygen deprivation syndrome. Wearing silicone hydrogel lenses can relieve the symptoms of oxygen deprivation syndrome. It can also prevent you from experiencing oxygen deprivation syndrome altogether.
- They offer more choices. Contact lens makers use silicone hydrogel to create a wider variety of lens designs. This includes contacts for astigmatism and hard-to-fit eyes, bifocal contact lenses, and custom contact lenses. Silicone hydrogel lenses can also be made for people with keratoconus – a progressive eye disease in which the cornea bulges into a cone-like shape.
There are some disadvantages to these lenses too. For example, they can get dirty more easily. Silicone hydrogel lenses can collect more debris and protein deposits from your tears. Some contact lens solutions may not work as well on these lenses as they do on hydrogel soft lenses.
Other drawbacks include:
- They can dry out on your eye. Silicone hydrogel contacts allow more oxygen to reach your cornea. But the added silicone can make it hard for these lenses to stay moist on the eye. (New contact lens solutions that keep these lenses hydrated for all-day wear are available.)
- They can be uncomfortable for people with minor cases of dry eye syndrome. Silicone hydrogel contact lenses can feel dry and uncomfortable for wearers with mild dry eye syndrome who switch from hydrogel lenses. Some people may mistake these symptoms for an allergy to silicone hydrogel contacts
Hydrogel and silicone hydrogel lenses each offer unique benefits and drawbacks, depending on your vision needs. Your eye care professional can help determine which is right for you.