Contact Lenses

Advantages of gas permeable lenses

• GP lenses allow your eyes to “breathe” better. GP lenses allow more oxygen to reach the front surface of the eye. 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.

The downside of GP contact lenses

So why doesn’t everyone wear GP lenses? 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. Initially, you may be able to wear the lenses only a few hours daily until your corneas adapt to them. But if you can tough it out for those first few days, you may be pleasantly surprised at how comfortable GP lenses become. Many people who switch from soft lenses to gas permeable lenses say GP lenses are more comfortable than soft lenses (after their eyes fully adapt) and their vision is noticeably clearer.
• Inability to wear part-time. To fully adapt to GP lenses and to stay comfortable wearing them, you have to wear them every day. If you stop wearing them for several days, you will be more aware of the lenses on your eyes and you’ll have to re-adapt to the lenses.
• Increased possibility of dislodging. Because they are smaller than soft lenses, gas permeable lenses can dislodge from your eyes during contact sports or if you rub your eyes aggressively.
• Vulnerability to sand and dust. GP lenses don’t conform to the shape of your eye like soft lenses do, so it’s possible sand or dust can get under your lenses at the beach or on a windy day. (You can minimize this risk by wearing wrap-style sunglasses outdoors.)
• Higher lens replacement costs. Unlike soft lenses, which come in limited sizes, GP lenses are custom-made to the shape of your eye. This makes GP lenses more expensive to replace if you lose them. Also, it can take up to a week to get a GP lens replaced.So it’s a good idea to purchase a spare pair to avoid the inconvenience of being without your GP lenses if you lose or break one.

Best of both worlds?

Since comfort is the primary barrier to GP use, an interesting innovation is the hybrid contact lens. These lenses have a GP center, surrounded by a soft lens “skirt.” The goal of hybrid lenses is to provide the clarity of a gas permeable lens and wearing comfort that rivals that of a soft lens.

Call for more information and a trial fitting

To see if gas permeable lenses are right for you, call our office for more information and to schedule a trial fitting.

It is not uncommon for patients to have difficulty wearing contact lenses for a number of reasons. Due to the individual eye shape, certain conditions or impairments or the aftermath of surgery, some patients are considered to be “hard to fit” as contact lens wearers.

For hard to fit patients that prefer to wear contact lenses however, there are options available that can provide comfortable and effective contact lens wear. This will require a specialized fitting with an eye doctor that is an expert that knows your condition and the various products available to find the right match for your specific condition. You may be considered a hard to fit contact lens candidate if you have one of the following conditions:

• Dry Eyes
• Astigmatism
• Giant Papillary Conjunctivitis (GPC)
• Keratoconus
• Pellucid Marginal Degeneration
• Post-LASIK or other refractive surgery
• Presbyopia (reduced near vision common in individuals aged 40 and over).
• Corneal Scarring

Dry Eyes and Contact Lenses

Dry Eye Syndrome causes your eyes to feel dry, gritty, burning, red, and irritated. Dry Eye Syndrome can also cause blurred vision. Often these symptoms can sometimes worsen by the use of contacts. In fact, many people who do not normally suffer from chronic dry eyes, will experience some of these symptoms as a result of contact lens wear.

First of all, if you have chronic dry eyes, you should see your eye doctor for treatment and relief before you think about contact lenses. Once your dry eyes are treated, it is safe to try contacts and there are a number of options that can be considered.

Many brands of soft contacts and products such as disinfectant and cleansing solutions are made with ingredients that are designed to be more comfortable for individuals with dry eyes. Your eye doctor will be able to recommend some of these brands and products to you. Alternatively, gas permeable (GP) or rigid gas permeable (RGP) lenses are made with a hard material that in some cases does not dry out like soft lenses and they are able to hold a certain amount of moisture beneath the lens to keep the eye from drying out. Gas permeable lenses are a very good option and can be quite comfortable for individuals with dry eyes.

Additionally, your doctor might recommend a specific wearing schedule such as limiting the time you wear your contacts throughout the day or replacing your contacts on a more frequent basis.

Toric Lenses for Astigmatism

Astigmatism is a condition that causes blurred vision (in some cases double vision) because rather than being round, the front of the eye (the cornea) has two curves instead of one, therefore, having two focal points instead of one. This makes it hard for traditional contact lenses to fit and therefore requires specialized contact lenses such as toric lenses or rigid gas permeable lenses (RGPs).

Toric contact lenses are designed to correct astigmatism and custom made to fit the eye of the patient. Most are made of soft material designed to stay in place on the eye, however in some cases, when the rotation of the lens (due to blinking and eye movement) can’t be stopped, gas permeable lenses might be tried. Due to the customization and more complicated fitting process required for these lenses, they are more expensive and take more time for the contact lens laboratory to make than traditional lenses.

Giant Papillary Conjunctivitis (GPC) and Contact Lenses

GPC is a type of conjunctivitis in which the inner surface of the eyelid becomes swollen. The condition can be caused or worsened by a buildup of protein deposits on contact lenses. Your eye doctor may either recommend daily disposable lenses or RGP lenses (which are not water based) and therefore do not have a tendency for protein buildup. Your doctor may also prescribe medicated eye drops and require you to stop the use of contact lenses until the symptoms improve.

Rigid Gas Permeable (RGP) or Gas Permeable (GP) Lenses

Rigid Gas Permeable (RGP) also known as Gas Permeable (GP) lenses are effective for many hard to fit patients. The hard, oxygen permeable material lets the eye breathe and significantly reduces the chance of infection due to protein deposits which tend to harbor bacteria on soft lenses. RGPs also hold moisture under the lens to keep eyes from drying out.

Rigid Gas Permeable (RGP) Lenses for Keratoconus

Keratoconus is a condition in which the cornea thins and bulges forward into a cone shape. Traditional contact lenses may cause some discomfort in these patients and the vision may still be blurry therefore RGPs are often used for treatment for mild, moderate, and some severe cases. Rigid gas permeable lenses may help to slow down the cone shape from worsening in some cases. Further, RGPs are able to assist in vision correction for keratoconus which is often not possible with soft contacts or even eyeglasses.

Post-LASIK or Vision Correction (Refractive) Surgery

While LASIK surgery has a very high success rate, there are vision complications and symptoms that sometimes remain. Night vision after LASIK, in particular, can sometimes give you side effects such as glare or halos around lights. RGPs are often effective in helping with these side effects and restoring clear vision.

Bifocal and Multifocal Contact Lenses for Presbyopia

Presbyopia is a common condition in those people usually over 40 years old iin which the eyes’ ability to focus on close objects is impaired. Many people keep a pair of bifocal or multifocal glasses on hand for times when they have to read menus, newspapers, books, and other objects that require near vision. For those that prefer contact lenses over eyeglasses, bifocal and multifocal contact lenses are an option.

For some patients that have presbyopia and need correction for distance vision as well, one option is monovision. Monovision is a contact lens fitting process in which you wear a contact lens in one eye for distance vision and the other contact lens of your other eye for near vision. Another option is multifocal contact lenses. In this contact lens fitting process, both eyes are usually fit for distance vision and both eyes are used for near at the same time. Both contact lens fitting options usually take about one week for the brain and the eyes to adjust.

If you have one of these conditions or find contact lens wear difficult for another reason, speak to your eye doctor. As technology improves there are more and more options for hard to fit contact lens patients to benefit from the comfort and convenience of contact lens use.

How ortho-k works

The GP lenses for ortho-k are applied at bedtime and worn overnight. While you sleep, the lenses gently reshape the front surface of your eye (the cornea) to correct your vision, so you can see clearly without glasses or contact lenses when you’re awake. The effect is temporary – generally enough to get you through a day or two – so you must wear the reshaping lenses each night to maintain good vision during the day.

Currently, there are two brands of orthokeratology approved by the FDA: Corneal Refractive Therapy (CRT) from Paragon Vision Sciences and Vision Shaping Treatment (VST) from Bausch & Lomb.

Who is a candidate for ortho-k?

Orthokeratology is frequently a good option for nearsighted individuals who are too young for LASIK surgery or for some other reason are not good candidates for vision correction surgery. Because it can be discontinued at any time without permanent change to the eye, people of any age can try the procedure, as long as their eyes are healthy.

Ortho-k is particularly appealing for people who participate in sports, or who work in dusty, dirty environments that can make contact lens wear difficult.

What results can you expect from ortho-k?

The goal for ortho-k is to correct your vision to 20/20 without eyeglasses or contact lenses during the day. In FDA trials of both CRT and VST lenses, more than 65% of patients were able to achieve 20/20 visual acuity after wearing the reshaping lenses overnight. More than 90% were able to see 20/40 or better (the legal vision requirement for driving without glasses in most states).

Success rates for ortho-k tend to be higher for mild prescriptions. Call our office to find out if your prescription is within the range that can be successfully treated with ortho-k.

How long does ortho-k take?

Though you may see some improvement in your vision after a day or two of overnight ortho-k, it can take several weeks for the full effect to be apparent. During this time, your vision will not be as clear as it was with glasses or contacts, and you are likely to notice some glare and halos around lights. It’s possible you may need a temporary pair of eyeglasses for certain tasks, like driving at night, until your vision is fully corrected by the ortho-k lenses.

Is ortho-k comfortable?

Some people have comfort issues when attempting to wear gas permeable contact lenses during the day. But since ortho-k GP lenses are worn during sleep, comfort and lens awareness are generally not a problem.

Cost of orthokeratology

Ortho-k is a significantly longer process than a regular contact lens fitting. It requires a series of office visits and potentially multiple pairs of lenses. Also, GP lenses used for ortho-k are more costly than most regular contact lenses. Therefore, fees for orthokeratology are higher than fees for regular contact lens fittings.

Can I have LASIK after ortho-k?

Yes, it’s possible to have LASIK surgery after orthokeratology. But because ortho-k lenses reshape your cornea, you must stop wearing the lenses for a period of time (usually several months) so your eyes can return to their original shape and stabilize. Be sure to tell your LASIK surgeon that you’ve worn ortho-k lenses, so they can advise you how long you should wait before having the surgery.

Astigmatism is a condition that is caused by an irregular shape of the cornea – the clear part of the eye that covers the iris and the pupil. The cornea is usually smooth, round, and spherical but in an astigmatic eye, the cornea turns into a shape that is not spherical and develops a second curve. One of the primary duties of the cornea is to focus light onto the retina which enables you to see clearly. When the cornea is out of shape and develops two curves, this created two focal points therefore causing blurred vision.

The irregular shape of the eye makes it hard for traditional contact lenses to fit and provide clear vision and therefore requires specialized contact lenses such as toric lenses or rigid gas permeable lenses (RGPs).

What are Toric Contact Lenses?

Toric contact lenses are designed to correct astigmatism and custom made to fit the eye of the patient. Rather than having a perfectly spherical surface like standard contact lenses, toric lenses have a more oblong shape made to accommodate the shape of the astigmatic eye. Toric lenses can be made of either soft or rigid gas permeable (RGP or GP) lens material, however the soft toric lenses are more common.

Toric contact lenses are also designed in such a way that the lenses stay in place on the eye to maintain proper vision. Sometimes as the eye moves or blinks the lens can rotate considerably on the eye. If this rotation continues with a soft toric lens, a rigid gas permeable lens might be more effective. Rigid gas permeable lenses have a longer initial adjustment time, but once this has passed they are usually just as comfortable as soft contact lenses and they are often easier to care for.

Toric lenses are available in every wearing schedule from daily disposable to long-term wear. In some cases you may even find colored toric contact lenses. Due to the customization required, toric lenses tend to be more expensive and may take more laboratory time to make than traditional lenses.

If you have astigmatism, finding the right fit for your contact lenses is essential. Speak to your eye doctor today for a full assessment to determine which type of toric lenses will work best for you to help you see and feel your best.