Rigid gas permeable contact lenses are rigid lenses made of durable plastic that transmits oxygen.
RGP contact lenses are rigid, but they shouldn’t be confused with old-fashioned hard contact lenses, which are now obsolete.
RGP practice represent a small but significant sector in the contact lens market. The reduction of RGP use in recent years is primarily contributed by the lack of instantly comfort of this type of lens wear, and RGP lenses require an adaptation period before they are as comfortable as soft contacts.
Unlike soft lenses, to achieve maximum comfort with gas permeable contacts, you need to wear them regularly (though not necessarily every day).
If you don’t wear your soft lenses for a week, they’ll still be comfortable when you put them on a week later. But if you don’t wear your GP lenses for a week, you’ll probably need some time to get comfortable again.
Also, RGP lenses are smaller in size than soft lenses, which mean there is a greater risk of gas permeable lenses dislodging from the eye during sports or other activities.
So, you may ask, why RGP?
In fact, RGP provides a superior optic which contributing to superior vision to high astigmatic corneas, approximately -2.50 diopter and above, by neutralising the astigmatism of the cornea.
You may find it useful if soft contact lenses failed to provide the desired vision. Also, because RGP 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.
The next interesting features about RGP is they’re made of materials that don’t contain water, therefore they are resistant to dehydration, protein and lipids from your tears do not adhere to GP lenses as readily as they do to soft lenses.
Surprisingly, the handling of RGP comes easier when compared to soft contact lenses. Although you can break them (for instance, if you step on them), you can’t tear and split 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 (generally one to two years), as long as you don’t require a prescription change.