Why gas permeable contact lenses

It required the user to blink frequently for lubrication and aeration of the eyes. Fortunately, gas permeable contact lenses have since been developed. Also known as rigid gas permeable RGP lenses, these are made of firm and durable plastic. They also incorporate silicon, making them more flexible than PMMA lenses.

Most importantly, they permit oxygen to pass through. After a comprehensive eye examination, our eye specialists may suggest these as part of your vision correction in Washington, DC.

They help those who have astigmatism and myopia. Post-refractive surgeries may also require these lenses. This type of contact lenses has brought comfort and convenience to its users. This reduces the risk of eye problems caused by hypoxia reduced oxygen supply. Gas permeable lenses provide a better oxygen supply than most soft lenses because: The silicone-containing lens materials of GP lenses are more permeable to oxygen than many soft lens materials though new "silicone hydrogel" soft lenses are comparable to GPs in oxygen transmission.

GP lenses are smaller in diameter than soft lenses, so they cover up less of the front surface of the eye the cornea. Gas permeable lenses hold their shape and move on the eye with each blink. This movement pumps oxygen-containing tears under the lens. Soft lenses conform to the shape of the cornea and have only minimal movement with blinks, so little or no tears circulate under soft lenses.

GP lenses provide sharper vision. Because they are custom-machined to a smooth surface and maintain their shape on the eye, GP lenses provide sharper vision than soft lenses, which can fluctuate in shape and clarity if they start to dry out. Gas permeable lenses also provide a more stable and accurate correction of astigmatism.

GP lenses last longer. GP lenses are rigid, so there's no worry about ripping or tearing them. They are also easier to keep clean and don't need to be replaced frequently like soft lenses. With proper care, a single pair of GP lenses can last a year or longer. And since they're long-lasting, GP can be less expensive than soft lenses in the long run. GP lenses may slow the progression of nearsightedness.

In addition to their other advantages, some research suggests that wearing gas permeable lenses may slow the progression of myopia nearsightedness in some children. GPs are also used for orthokeratology, where specially designed contacts are worn during sleep to reshape the cornea and improve vision.

Potential disadvantages of GP lenses compared to soft lenses include: Need for adaptation. Unlike wearing soft lenses which are comfortable right from the start , you may need few weeks before you can wear GP lenses comfortably all day.

Different bifocal designs work well for different people, so having many choices is a real plus. Also, many people find that the best combination of near and distance acuity is obtained with GP bifocals. People who have a condition called keratoconus , where the cornea is cone-shaped and causes extreme visual distortion.

People who need contact lenses after refractive surgery. Gas permeable contacts also are used for ortho-k , where specially designed GP lenses are worn during sleep to reshape the cornea and improve vision.

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, GP lenses are smaller in size than soft lenses, which means there is a greater risk of gas permeable lenses dislodging from the eye during sports or other activities. And because gas permeable lenses are designed to move on the eye when the wearer blinks, there is a higher risk of dust and debris getting under the lenses, causing discomfort or a possible abrasion to the cornea.

Finally, GP lenses do require care , since they are reused for one year or more. 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.

SynergEyes Duette hybrid contacts have a rigid GP center for clear optics, surrounded by a soft outer zone for added comfort. 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.

The company makes a variety of hybrid lenses sold under the Duette, UltraHealth and SynergEyes brands, including progressive and multifocal hybrid lenses for the correction of presbyopia and designs for the correction of keratoconus and other corneal problems. For more information about gas permeable lenses, visit the GP contacts educational website provided by the Contact Lens Manufacturers Association. Also, consult with your eye doctor and ask if gas permeable contacts or perhaps hybrid contact lenses are the best choice for your lifestyle and visual needs.