Also known as GPs or Oxygen Permeable lenses, gas permeable lenses are often confused with hard lenses. This is because both lenses are made of rigid materials. Hard contact lenses were conventionally made from a material known as Polymethyl Methacrylate (PMMA) which is now obsolete. The reason for the abandonment of the use of PMMA for soft contact lenses and then GP lenses is that they did not allow any oxygen to flow through the lens and into the eye and were very uncomfortable to wear. Unlike traditional contact lenses, GP lenses need to be custom made according to the needs of the wearer and are only long term. This is because they are part of a treatment procedure to correct any refractive disorders within the eye. The most common eye disorder treated with Gas Permeable Lenses is Astigmatism. The only drawback to gas permeable lenses is that they cause much more discomfort to the wearer than soft contact lenses.
Gas permeable lenses are much more durable than regular soft contacts since they are made of a more rigid material. This means they have a longer life and can be worn for up to a year. These lenses are also less susceptible to damage.
Moisture is one of the most important things for an eye since it has direct contact with the environment. GP lenses help eyes retain their moisture and don’t absorb the natural tear solution created within the eye. This way the eye remains moist during wear making them more comfortable.
The entire premise of this corrective lens is to make sure that the eye receives much needed oxygen. These lenses are made from special permeable material that allows oxygen to pass through to the ey making them less prone to bacteria.
Cost of Use
The GP lens is much heavier than the soft contact lens. These lenses are used to correct astigmatism. In astigmatism, the shape of the individual’s eye is more oblong than round causing the light to refract on different angles rather than create one focal point. GP lenses correct the shape of the eye and are more reliable since they are heavy set and have restricted movement.
Unlike soft contacts, many bifocal features can be incorporated into the GP lens. These include bitoric, front toric and prism ballast along with multifocal features. This means that they can be used to help individuals suffering from presbyopia.
Since Gas permeable lenses have a smooth finish and do not retain water, they are less likely to accumulate any protein deposits that may result from the natural tear film over the eye. This means that they harbor lesser bacteria and are also much more comfortable to wear.