For contact lens wearers, finding the right lens fit can increase comfort, reduce irritation and improve visual acuity. For those who experience irritation when wearing contacts due to decreased oxygen flow to the cornea, oxygen flow gas permeable or silicone contact lenses can provide an enhanced option over traditional soft or hard lenses.
Significance
Silicone contact lenses were designed as an upgrade to traditional soft contact lenses. Produced from a material known as senofilcon A, a silicone hydrogel material, the silicone contact lenses are designed to minimize dryness and discomfort reported in contact lens wearers, according to Medical News Today. Oxyen flow gas permeable lenses typically also contain some silicone material to reduce irritation. However, these lenses contain other materials designed to increase visual sharpness by holding its shape when you blink.
Texture
Silicone contact lenses are a form of soft contact lens, which means the lens bends easily in order to fit over the eye. This allows more oxygen to flow through the contact, according to the U.S. Food and Drug Administration. Gas permeable oxygen flow lenses are designed to be rigid, meaning they are not as flexible as soft contact lenses like the silicone contact lenses.
Oxygen Transmission
Oxygen transmission is an important aspect of contact lens wear because oxygen passes through the cornea to reduce irritation, according to MayoClinic.com. Oxygen flow gas permeable lenses were invented to provide more oxygen flow than previous gas permeable lenses. While these gas permeable lenses allow more oxygen flow than most soft contact lenses, some silicone lenses allow for equal oxygen flow as gas permeable lenses, according to All About Vision. However, some silicone lenses do not have the oxygen transmission capabilities that gas permeable lenses have.
Adjustment Period
Oxygen flow gas permeable lenses require an adjustment period in order for you to become accustomed to the contact's rigid feel over the eye, according to All About Vision. This is true if you stop wearing your gas permeable lenses for a week, then resume wearing them again. However, silicone lenses are designed to be comfortable upon first wear and should feel more natural on the eye.
Wear
Silicone hydrogel lenses allow for enough oxygen flow that they can be worn for up to 30 days consecutively if your contact brand is made for this duration, according to All About Vision. However, some brands provide for anywhere from six nights to two weeks. Gas permeable lenses must be removed daily and stored in a sterile solution made for contact lenses.
References
- All About Vision: Silicone Hydrogel Contact Lenses
- All About Vision: Gas Permeable Contact Lenses
- The University of Michigan Kellogg Eye Center: Contact Lenses
- U.S. Food and Drug Administration: Types of Contact Lenses
- MayoClinic.com: Contact Lenses
- Medical News Today: Contact Lens Made with Silicone Hydrogel
