Understanding RGP contact lenses
RGP contact lenses are especially suitable for those with a large or complicated prescription and can provide high levels of comfort and clarity.
Gas permeable contact lenses are rigid lenses made of durable plastic that transmits oxygen. These lenses also are called GP lenses, rigid gas permeable lenses, RGP lenses and oxygen permeable lenses.
GP contact lenses are rigid, but they shouldn't be confused with old-fashioned hard contact lenses, which are now essentially obsolete. Gas permeable contacts were first introduced in the late 1970s; they are actually a newer technology than soft lenses. Most GP lenses incorporate silicone.
Silicone is oxygen permeable, so oxygen can pass directly through GP lenses to keep the cornea healthy without having to rely solely on oxygen-containing tears to be pumped under the lens with each blink.
In fact, modern rigid gas permeable contacts allow more oxygen to reach the cornea than most soft contact lenses (although some silicone hydrogel soft lenses are comparable to GP lenses in oxygen transmission).
Because gas permeable contact lenses allow oxygen to pass through them, GP lenses can be made larger than PMMA hard contact lenses, and the edges of GP lenses can be fitted closer to the surface of the eye. These design changes make modern rigid GP lenses more comfortable and easier to get used to than old-fashioned hard contacts and also keep the lenses more securely on the eye when worn during sports and other activities.
RGP lenses also provide better vision, durability, and deposit resistance than soft contact lenses. And because they last longer than soft lenses, they can be less expensive in the long term.
The Benefits of RGP Lenses
Gas permeable contact lenses offer some outstanding benefits over soft lenses. For one, because GP lenses are made from a firm plastic material, they retain their shape when you blink, which tends to provide sharper vision than pliable soft lenses.
GP lenses also are extremely durable. Although you can break them (for instance, if you step on them), you can't tear them easily, like soft lenses.
And they're made of materials that don't contain water (as soft contact lenses do), so protein and lipids from your tears do not adhere to GP lenses as readily as they do to soft lenses.
With a little care, gas permeable contact lenses can last for years, as long as you don't require a prescription change.
Hybrid Contacts: The Best of Both Worlds?
Since comfort is the primary barrier to greater popularity of gas permeable lenses, hybrid contact lenses are an excellent choice for people who want the clarity of a GP lens and wearing comfort that more closely resembles that of soft lenses.
Hybrid contact lenses have a central optical zone that is made of a gas permeable lens material, surrounded by a peripheral fitting zone made of silicone hydrogel or regular hydrogel soft lens material.
Keep it in the family
Even if no-one in the past few generations of your family had blue or green eyes, these recessive traits can still appear in children born in the future.