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Posts Tagged ‘contact lenses’

Christian’s Keratoconus Story – “ClearKone Changed the Way I See Life”

Thursday, June 23rd, 2011

My vision challenges began in junior high school when I started to wear glasses. Although my vision was fine at that time, things started to change when I entered high school. I began to notice that I wasn’t able to read the chalkboard. Even though I sat in the front row, I found it difficult and frustrating to read the teachers’ notes. I went back to my optometrist, who gave me another pair of glasses with a stronger prescription. Unfortunately, the new glasses only helped for a period of time. By the time I was in my junior year, my vision was a problem again. The new glasses no longer corrected my vision. I decided it was time to see a new optometrist. 

In my senior year of high school my new optometrist, Dr. Barry Leonard, diagnosed me with keratoconus. While I was glad to have found out the cause of my vision problems and learn that contact lenses could improve my eyesight, I could never have imagined the contradictions that came with contact lens wear. My doctor fit me in RGP lenses, which did improve my vision, but the lenses were so uncomfortable. My eyes were often irritated, so I would try to function without wearing the lenses. Unfortunately, my vision was so poor without them that I could not drive, see faces of friends at a distance, or read a book with small font. Keratoconus was truly affecting my daily activities!

Dr. Leonard then recommended that I try the ClearKone lens from SynergEyes. He explained that the rigid center would give me the visual acuity I needed, while the soft skirt would keep my eyes comfortable throughout the day. It sounded like a great option! As we began the fitting process, it was difficult for my lids to open wide enough for the lenses to be inserted. My eyes were so sensitive that my lids would close whenever the lens got near my eye. Thankfully, Dr. Leonard was very patient with me, and after many attempts, was able to insert the lenses.

Once I began wearing the lenses, I was amazed. My vision was clear and crisp, and the lenses were so comfortable that I could wear them all day long without irritation. It really was the best of both worlds!

I have now been wearing the lenses for several months, and my life has changed in so many ways. I can distinguish faces from a distance and see their expressions, which is so wonderful! I am also able to drive, use the computer, and read books with small font. I feel like I now have a normal life without the frustrations of poor vision. ClearKone lenses have truly changed the way I see life!

Contact Lens Options for Keratoconus

Monday, October 18th, 2010

Author:  Dr. Anderson, OD, FAAO

Keratoconus is a bilateral, progressive corneal thinning disorder which manifests as irregular, asymmetric astigmatism. Symptoms include blurred, subacute distorted vision which is usually more pronounced in one eye than the other. Refraction is often difficult and patients may not be adequately corrected with spectacles. Contact lenses are the best form of visual correction in most cases of clinically significant keratoconus. There are many different types of contact lenses available for keratoconus. Depending on the degree of clinical significance, lifestyle and ocular health, the optimal contact lens can be determined for each patient. This article describes the different design options currently available, along with the goals to keep in mind when fitting these patients.

Soft Toric Lenses

Many times, patients in the early stages of keratoconus do well with soft lenses. A satisfactory baseline refraction, which will most likely have a moderate amount of cylinder, is necessary in order to determine the soft lens prescription, which will most likely be toric. Occasionally, a spherical equivalent will produce good visual results. Patients with forme fruste keratoconus may also do well with soft toric lenses since adequate spectacle refraction is often possible.

Rigid Gas Permeable (RGP) Lenses

RGPs are the most commonly prescribed lenses for keratoconus. Traditionally, these lenses were fit with small diameters, three-point touch and variable edge lifts to improve comfort. However, this type of fit often results in a low-riding lens, decentered inferiorly over the pupil which induces aberration. More recent RGP designs for keratoconus have incorporated aspheric or biaspheric optics to decrease aberration, along with larger diameters to improve centration.

Piggyback Systems

Keratoconus patients who are currently fit with RGP lenses oftentimes experience discomfort and decreased wearing time as their condition progresses. The cone steepens and the apex thins to the point of inflammation, abrasion and irritation from RGP bearing. A simple way to halt this cascade of events is to place a soft lens beneath the RGP. Using a low minus power will flatten and protect the corneal surface as well as improve the comfort and wearing time. High Dk soft and RGP materials work well to maintain corneal integrity by decreasing the incidence of neovascularization.

Hybrid Lenses

These lenses consist of an RGP center with a soft skirt edge. They combine the benefits of rigid lens optics, including better lens centration and decreased aberrations, along with the comfort of a soft lens. The results are improved vision and increased wearing time. This is especially beneficial in keratoconus patients whose cone apex is very steep, thin and decentered. Traditional small diameter RGP lenses tend to decenter downward over the apex, inducing bothersome aberrations over the pupil. SynergEyes is currently the only manufacturer of hybrid lenses in the U.S. The designs available for keratoconus include the SynergEyes A, KC and ClearKone. Patients with mild to moderate keratoconus may fit into the A lens which has a spherical RGP center. The KC lens has an aspheric RGP center and is reserved for more advanced cones. ClearKone consists of a reverse geometry RGP center which is fit upon elevation or sagittal depth rather than base curve. This allows for clearance, centration and stabilized vision over a decentered cone. Because it achieves clearance by vault, ClearKone offers lower powers and reduced aberrations as compared to lenses fit according to base curve.

Scleral/Semiscleral Lenses

Rigid gas permeable lenses with diameters of 13mm or greater fall into this category. The benefits of these large diameter RGPs in keratoconus are a large,well-centered optic zone, minimal movement with blink, stabilized vision and improved comfort. Fitting these lenses requires a great deal of skill, which is acquired from experience. The dynamics are quite different from corneal lenses. The parameters of the larger periphery determine the patient’s ability to wear the lens comfortably and must be fit independently of the central base curve. The ultimate goal in fitting any keratoconus patient with contact lenses is good vision and comfort. This is relatively easy to achieve in early cones and becomes more difficult as corneal thinning and steepening progress. Determining the best lens to fit in order to achieve these goals is as much of an art as it is a science. For example, a patient who has worn small diameter RGPs unsuccessfully may do better in a hybrid or semi-scleral design. Regardless of lens design, finding the best lens begins with careful measurement of corneal curvature and diagnostic lens fitting.

Keratoconus Treatment Options

Friday, September 3rd, 2010

By Dr. Brandon Ayres, MD

Keratoconus causes progressive thinning and distortion of the cornea that affects approximately 1 in every 2000 people.  It tends to affect younger people sometimes starting in the early teen years and progresses most rapidly through the fourth decade.  As the dystrophy progresses the cornea takes on an irregular cone like shape and may develop scar tissue.  The changes in the cornea seen in keratoconus lead to “irregular astigmatism.”  Irregular astigmatism means that light is not able to focus on the retina even with the use of glasses or traditional soft contact lenses.

The primary treatment options fall into two categories:  contact lenses and surgery.  This article outlines both options.

Glasses and Contact Lenses

In the very early stages of keratoconus patients may notice a change in their prescription glasses or contact lenses.  Often times what is seen is an increase in astigmatism.  If the keratoconus progresses only minimally, all that will be needed is modification of the glasses prescription or possibly a soft contact lens that also corrects for astigmatism.

Keratoconus Contact Lenses

Once patients with keratoconus are dissatisfied with there vision with traditional glasses or soft contact lenses a special keratoconus contact lens may be necessary.  Most commonly this contact lens will be either a hybrid or rigid gas permeable (RGP) contact lenses.  It is important to understand that contact lenses may allow excellent vision, but do not actually treat or stop the progression of the underlying dystrophy.

A rigid gas permeable contact lens is able hold it’s spherical shape vaulting over the irregular cone shape of the irregular cornea.  This gives a new smooth surface to refract light, restoring good vision.  The use of an RGP is an excellent, non surgical, technique to restore vision in keatoconus,  but the fitting of the lens can be quite challenging.  Each patient with keratoconus has a uniquely shaped cornea and the shape may change over time.  Many different designs of RGP’s are available for patients with keratoconus and patience is needed to get the right fit.  Most people with keratoconus are able to be successfully fit with RGP’s, however, some have persistent foreign body sensation or difficulty with the lenses falling out of the eye.

Hybrid contact lenses work on a similar principal as RGP’s.  This style of contact lens has a rigid gas permeable center that is fused to a soft contact lens “skirt” and therefore a hybrid of hard and soft contact lenses.  By fusing the two styles of contact lenses the visual benefit of a RGP is combined with the comfort of a soft lens.  As with the traditional RGP, these lenses must be specially fitted to ensure function, comfort, and safety.

Surgical Options

Collagen Crosslinking (CXL)

Collagen crosslinking is a technique that is currently under FDA trial here in the United States, but widely available outside the country.  Collagen crosslinking is a technique where vitamin B2 (also known as riboflavin) in liquid form is placed on the cornea.  The cornea is then exposed to ultravioled light (UV-A).  The combination of vitamin B2 and UV light increases the “linkages” in the corneal collagen.  This has been shown in laboratory studies to “stiffen” the cornea.  The goal of collagen crosslinking is to prevent progression of the keratoconus, not to reverse or cure it.

INTACS® Corneal Inserts

INTACS corneal inserts are small inserts that are placed in the cornea.  These inserts help “flatten” the central cone of the cornea in patients with keratoconus.  Once surgically implanted in the cornea the inserts are almost invisible and they cannot be felt.  INTACS have been shown to help with improvement in corrected and uncorrected vision.  INTACS can also be helpful in improving contact lens tolerance by reducing the conical shape of corneal in patients with keratoconus.  Recent studies have shown continued improvement in patients having INTACS placed over the course of 1 year and there is some suggestion that they may help stabilize the cornea.

Corneal Surgery

Approximately 20% of patients with keratoconus will have progression to the degree where corneal surgery is necessary.  The most common procedure performed is a full thickness corneal transplant also know as a penetrating keratoplasty (PKP).  In this surgery the diseased corneal is removed and replaced by a human donor cornea.  Luckly, transplantation of the cornea is the most successful of all organ transplants with a low rejection rate.  The vast majority of patients will achieve excellent vision after a transplant though it may take 12 to 18 months to achieve.  Many patients will still need the assistance glasses or contact lenses for optimal vision.

A second surgical option for keratoconus is a deep anterior lamellar keratoplasty (DALK).  This procedure is essentially the same as a corneal transplant except that the very thin innermost layer of the patient’s cornea, called the endothelium, is spared.  The surgery will look and heal very similar to a corneal transplant except that there is a lower chance for transplant rejection.  The surgery is technically much more challenging for the surgeon and sometime has to be converted into a full thickness transplant.

Most recently there has been an interest in using a laser to make the incisions for both corneal transplants and DALK surgical procedures.  The laser-guided incisions allow for an exact match of the patient and donor corneas.  The exact fit allows for a stronger wound and possibly faster healing with less residual astigmatism after the surgery.

Keratoconus Causes and Treatment Options

Saturday, July 31st, 2010

By: Clark Chang, OD, MS, FAAO

Keratoconus Causes

Keratoconus is a non-inflammatory, progressive corneal condition associated with corneal thinning, weakening, and steepening, resulting in corneal optical irregularities (cone shape) and poor vision. An incidence rate of 1:2000 has been reported with no known sexual or ethnic predilection. In addition, familial inheritance has been reported in 6-24% of cases and co-morbidities such as atopic disease and connective tissue diseases have also been reported in the literature. Thus, genetic predisposition, acute eye allergies, and eye rubbing (often as allergic response) have all been proposed as potential underlying causes of keratoconus development. However, no definite causative factor(s) have been proven.

As keratoconus progresses in severity, the increasingly irregular shape of the eye causes optical side effects known as higher order aberrations (think of static noise for TV signals). These aberrations are primarily responsible for the reduction in one’s visual functions.  Corneal transplant has traditionally been utilized as the choice of medical treatment for the misshapen cornea. However, the reconstructed tissue interface does not always restore the cornea to its normal (spherical) shape, which means contact lenses are still needed to treat keratoconus after corneal transplantation1. Therefore, with the recent advancements in contact lens technology, non-surgical management methods have been recognized as the leading treatment choice in visual rehabilitation for keratoconus patients. Surgical options are currently being preserved for individuals who either cannot tolerate contact lenses or cannot achieve satisfactory vision with contact lenses2.

Keratoconus Contact Lens Treatment Options

Rigid Gas Permeable lenses (RGP) provide good visual outcomes, which make it the most widely utilized method in rehabilitating an irregular corneal surface. The firm structure of an RGP lens allows a layer of tear fluid to form beneath the lens; the tear layer fills in the irregularities between the cornea and the lens, and the combination of the smooth outer lens surface and the tear layer neutralizes the visual distortions. However, the advantages of good visual outcome and ease of lens handling may not always outweigh the amount of time it takes to adapt to RGP lenses and the issues of discomfort and the potential for RGP lenses to “pop out” of the eye. Therefore, alternative non-surgical treatment options have been developed to overcome such issues.

Because most soft lens materials are flexible they drape over the cornea. If the cornea is irregularly shaped, a soft lens will take the shape of the irregularities hence, this treatment option is only used for patients with very mild keratoconus. Nonetheless, recent custom soft keratoconus lens designs employ enhanced lens thickness in an attempt to mimic the optical benefits offered by RGP lenses. While oxygen permeability may be a concern until new material becomes available, the soft keratoconus lens provides a viable alternative for patients with mild to moderate keratoconus who cannot tolerate an RGP lens.

RGP intolerance mainly stems from irritation caused by the lens touching the eye.  A carefully selected bandage soft lens can be placed under the RGP lens in a piggyback system, which decreases irritation and helps stabilize the RGP lens on the eye. However, handling the two-lens system can be complex and inconvenient as there is a potential for reduced oxygen supply to the eye3.

Hybrid lens technology has enabled the bonding of an RGP lens with a soft lens so a single lens system offers both improved visual quality and increased wearing comfort. The recent advances in the 4th generation hybrid lens, ClearKone®, utilize a uniquely designed RGP lens shape to expand on its previous fitting parameters to include patients through all stages of keratoconus. Fitting success rates up to 86.9% have been reported utilizing hybrid lens platforms on keratoconus patients.

Recently improved oxygen permeability in RGP lens materials led to the clinical resurgence of scleral lenses. Scleral lenses comprise the largest diameter lenses within the family of non-surgical treatment options. A scleral lens design can often be more comfortable than its smaller RGP counterpart because a scleral lens design allows its lens edge to rest on sclera (white part of the eye), which has much lower sensitivity than one’s cornea. In addition, similar to the 4th generation hybrid lenses, sclera lenses are designed so the lens does not bear on the cornea, which minimizes irritation. Up to a 93% fitting success rate has been described with modern scleral lens designs1.

Because of the larger lens diameters in both the hybrid and scleral lenses, in comparison to the conventional RGP lenses, the insertion and removal process is different and requires practice during the initial adaptation period. This can hold true even for patients that have worn contact lenses before.

A well-fitted contact lens not only defers the need for more invasive surgical procedures but also significantly improves the quality of one’s vision and life. However, this process requires the combined ingredients of a physician’s clinical expertise and a patient’s determination. Further, it is essential for both the physician and the patient to recognize that no single lens design currently encompasses the complexity of all fitting situations. An open and honest discussion regarding one’s visual expectations and daily functional tasks performed in real life environment can be meaningful in the selection of a tailored management choice from the many non-surgical options that exist today.

Reference

1. Rosenthal P. Evolution of an Ocular Surface Prosthesis. Contact Lens Spectrum. 2009 Dec: 24(12):32-38

2. Garcia-Lledo M, Feinbaum C, Alio JL. Contact lens fitting in keratoconus. Compr Ophthalmol Update. 2006 Mar-Apr; 7(2):47-52.

3. Rosenthal P. Evolution of an Ocular Surface Prosthesis. Contact Lens Spectrum. 2009 Dec: 24(12):32-38.

4. Garcia-Lledo M, Feinbaum C, Alio JL. Contact lens fitting in keratoconus. Compr Ophthalmol Update. 2006 Mar-Apr; 7(2):47-52.

5. Nau AC. A comparison of Synergeyes versus traditional rigid gas permeable lens designs for patients with irregular corneas. Eye Contact Lens. 2008 Jul;34(4):198-200.

6. Abdalla YF, Elsahn AF, Hammersmith KM, Cohen EJ. SynergEyes lenses for keratoconus. Cornea. 2010 Jan;29(1):5-8.

Patient Success Stories

Saturday, July 31st, 2010

“I saw for the first time – the world as it really looks”

“I have SynergEyes UltraHealth Contact Lens in both eyes. I have worn them daily at least 15 hours, even once 22 hours straight.

I have been wearing them now for over 6 months and my vision is superb, comfort supreme, not cloudy, not blurry, and no pain. I am 66 years old, was diagnosed with Keratoconus over 50 years ago, had a corneal transplant in my left eye 40 years ago, and still working great. I have only worn hard contact lenses (no glasses) my entire working life with a full career.

My words of wisdom to all you “Keratoconiacs” out there – “Your Fitter is your key to success!”

Theresa W.,   Age 66

How is Keratoconus Diagnosed?

Thursday, July 29th, 2010

The initial symptoms of keratoconus include frequent and significant changes in a patient’s eyeglass prescription, especially in the amount of astigmatism. This is often followed by progressive vision problems such as halos, glare symptoms, ghost images, double and multiple images perceived by each eye individually, and by numerous attempts at obtaining a good glasses prescription without success.

Early diagnosis is very important in the management of keratoconus. New advanced technologies allow eye doctors to detect and treat the condition very successfully. The most sensitive diagnostic method available for keratoconus detection is corneal topography. This allows the doctor to evaluate the shape of the cornea. The most commonly used topography instruments only measure the front surface of the cornea; however more advanced forms of topography evaluate both the front and back surface of the cornea as well as corneal thickness profiles. This is critically important since the earliest abnormalities found in keratoconus will develop initially on the back surface of the cornea and tend to always be more advanced than the front surface irregularities. Other diagnostic tests may also detect keratoconus at very early stages and also discover progression early on. These include aberrometry techniques which measure various forms of visual distortion, and corneal optical coherence tomography (OCT) which provides exquisitely detailed imaging of the cornea.



Pentacam Corneal Topography

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Pentacam Corneal Topography measuring both the front and

back surface of the cornea as well as corneal thickness profiles.




Aberrometry

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Aberrometry measures vision distortions in keratoconus




Optical Coherence Tomography

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Optical Coherence Tomography (OCT) keratoconus



« READ “What is Keratoconus?” | READ “Non-Surgical Treatment Options” »

Common Questions about Contact Lenses and Keratoconus

Saturday, July 10th, 2010

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To submit a question, please send an email to askanexpert@synergeyes.com. We will review all questions and post an answer each week.

Please note: If you have an urgent question about your eye health, contact your eye care practitioner immediately. This page is designed to provide general information about vision, vision care and vision correction. It is not intended to provide medical advice. If you suspect that you have a vision problem or a condition that requires attention, consult with an eye care professional for advice on the treatment of your own specific condition and for your own particular needs.

Common Keratoconus Questions

Friday, July 2nd, 2010

What is keratoconus?

Keratoconus is a degenerative eye disease that causes the cornea to thin and bulge, creating a cone-like irregular shape. Because the cornea is responsible for refracting most of the light that comes into the eye, any irregularity of the cornea can result in significant visual impairment.  Keratoconus most often appears in a person’s late teenage years; although it has been diagnosed in people in their forties and fifties. The eye disease has been estimated to occur in roughly one out of every 2,000 people in the general population. No significant geographical, gender, ethnic, or social pattern has been established, and keratoconus occurs in all parts of the world.

What causes keratoconus?

The exact cause of keratoconus is not known; however, there are many theories on what may trigger this disease. It is important to note that no one theory provides a complete explanation, and it is likely that keratoconus is caused by a combination of things.

It is believed that genetics, the environment, and the endocrine system all play a role in keratoconus:

Genetics: Although keratoconus sometimes affects more than one member of the same family, current research indicates that there is less than a one in ten chance that a blood relative of a keratoconic patient will have keratoconus.

Environmental Factors: Keratoconus may also be associated with overexposure to ultraviolet rays from the sun, excessive eye rubbing, a history of poorly fit contact lenses and chronic eye irritation.

Endocrine System: Another hypothesis is that the endocrine system (which dictates the release of hormones) may be involved, since keratoconus is often first diagnosed in adolescence.

What are the symptoms of keratoconus?

Blurred and distorted vision and frequent eyeglass prescription changes are the first signs of keratoconus. However, blurred and distorted vision occurs as a result of many other types of eye disease, so it is important to visit an experienced eye care professional for diagnosis immediately when noticing any changes in vision. Typically keratoconus occurs in both eyes with one eye more severe than the other. Additional symptoms of keratoconus include:

  • Increased light sensitivity
  • Difficulty driving at night
  • Halo’s and ghosting (especially at night)
  • Eye strain
  • Headaches and general eye pain
  • Eye irritation and excessive eye rubbing

How is keratoconus treated?

Keratoconus is primarily treated with contact lenses because glasses cannot to visually correct the irregular form of the cornea. Surgical treatment options are also available and are typically used when contact lens wear is no longer possible.

Contact Lens Treatment Options

Hybrid Contact Lenses

Hybrid contact lenses are the latest and most advanced option available in contact lenses specifically designed for keratoconus and irregular cornea patients. Using a revolutionary technology, hybrids combine the best of both worlds – the crisp vision of a high-oxygen rigid gas permeable (RGP) contact lens with the all-day comfort and convenience of a soft lens. Hybrids are specifically designed to restore vision to patients with the many types and stages of keratoconus. Because the lens design vaults over the cornea, there’s minimal risk of corneal scarring, making hybrid lenses a healthy treatment option for keratoconus. In addition, the soft skirt of the hybrid design helps to center the contact lens over the visual axis regardless of where the cone is located on the cornea or how large it is, thereby decreasing visual distortions and providing superior vision. The hybrid design also prevents dirt from getting under the lens and will not pop out unexpectedly. No other contact lens available today can provide all of these benefits in a single product.

Rigid Gas Permeable (GSP) Lenses

RGP lenses are made from a rigid material that does not drape over the irregularly shaped cornea, but rather, holds its shape and creates a layer of tears between the cornea and the back surface of the lens. This tear layer neutralizes the irregular shape of the cornea. Consequently, RGPs provide better vision than soft lenses. Unfortunately, for those with keratoconus, RGPs may not provide adequate vision correction. This is because RGP lenses tend to migrate toward the location of the cone, which is usually not on the visual axis, which is near the center of the cornea. For this reason, patients who wear RGPs typically experience problems with inconsistent vision. Furthermore, RGPs are often uncomfortable, inconvenient, allow dirt to be trapped under the lens and may pop out. They can also lead to corneal scarring because they are commonly designed to fit touching the surface of the cone.

Scleral Lenses

Scleral lenses are very large RGP lenses that can provide adequate vision but often require very precise and skilled fitting by your eye care professional. Sclerals occasionally have to be removed and reinserted with fresh saline during the day to keep your vision clear and comfortable.

Soft Contact Lenses

Soft contact lenses are comfortable but are usually unable to visually normalize the irregularities of the keratoconic cornea and therefore do not provide acceptable vision. Soft lenses drape over the irregular corneal surface causing the surface of the lens to assume the same irregular shape as the cornea. This abnormal shape is the reason for blurred and distorted vision. As the cornea becomes more irregular, soft lenses become less effective.

Piggyback Lenses

“Piggyback” lenses are RGP’s and soft lenses that are worn at the same time. In some cases, this approach may be more successful than soft or RGP lenses alone, but because of the complexities of handling and care, possible eye health problems due to the decrease in oxygen able to move to the cornea through both lenses, and difficulty with lens centration, success rates are marginal.

Surgical Treatment Options

Patients with keratoconus often ask “Can I have surgery to correct my keratoconus?” There are surgical options that are designed to strengthen, reshape or replace the irregular surface of a keratoconic cornea, and perhaps lessen the impact of keratoconus, but unfortunately none will reverse the progression that has taken place.

The most common surgical treatment options for keratoconus are: Intacs®, corneal collagen crosslinking, corneal transplant or some combination of these procedures.

Intacs®

Intacs are semi-circular plastic implants that are inserted into the middle of the cornea. The intent is to re-shape the cornea to a more normal shape to improve vision. Commonly Intacs do not leave the cornea completely regular in shape, and contacts are still needed for further correction. Intacs are used to improve the patient’s vision, and possibly delay or eliminate the need for a corneal transplant.

Corneal Collagen Cross-linking (CXL)

A new treatment option called corneal collagen cross-linking (CXL) is currently undergoing FDA clinical trials in the United States to determine its safety. With the corneal crosslinking procedure, custom-made riboflavin drops saturate the cornea, which is then activated by ultraviolet-A light. This process has been shown in laboratory and clinical studies to increase the amount of collagen cross-linking and strengthen the cornea

Corneal Transplant

A corneal transplant is a surgery in which a plug of approximately 7.5mm–including the steepest, most irregular part of the cornea–is removed and replaced with corneal tissue from a donor eye. The transplanted tissue is then sutured into place. Lamellar Keratoplasty is a relatively new technique which involves removal of only a partial thickness of the cornea. The theoretical advantage is a lower risk of rejection because the major target for corneal rejection is not transplanted. The resulting cornea is generally flatter and smoother than before, but most often there are still irregularities that are best corrected by a contact lens.

What is a hybrid contact lens?

Hybrid contact lenses are an advanced contact lens option specifically designed for keratoconus and irregular cornea patients. The center of the lens is an RGP and it is surrounded by a soft lens material.

 

Information:

Remember when you had only two choices in contact lenses? “Hard” (RGP) lenses provided GOOD vision, but were often irritating and uncomfortable. Soft lenses offered GOOD comfort, but couldn’t correct your vision problems. Now, a technological breakthrough makes having to compromise a thing of the past. Hybrid contact lenses offer all the benefits of RGP and soft contact lenses without any of the disadvantages for an overall GREAT contact lens experience. Using a revolutionary technology, hybrids combine the best of both worlds – the crisp vision of a high-oxygen rigid gas permeable (RGP) contact lens with the all-day comfort and convenience of a soft lens. Hybrids are specifically designed to restore vision to patients with the many types and stages of keratoconus. Because the lens design vaults over the cornea, there’s minimal risk of corneal scarring, making hybrid lenses a healthy treatment option for keratoconus. In addition, the soft skirt of the hybrid design centers the contact lens more closely over the visual axis regardless of where the cone is located on the cornea or how large it is, decreasing visual distortions and providing superior vision. The hybrid design also prevents dirt from getting under the lens and will not pop out. No other contact lens available today can provide all of these benefits in a single product.

The History of Hybrid Lens Technology

Thursday, July 1st, 2010

Patient excitement for a contact lens is created when the first lens placed on the eye provides good vision and feels great.  Success in contact lens wear depends upon the patient achieving their vision, comfort and eye health goals. At one time patients could only choose between rigid gas permeable lenses (RGPs) and soft lenses so patients often had to compromise on either vision or comfort. Today there is another technology option available called the hybrid contact lens. A hybrid contact lens combines the superior vision benefits of an RGP lens with the comfort benefits of a soft lens.  Hybrid lenses have come a long way since they were conceived in 1977.  Now in the 4th generation, the hybrid lens category has evolved to offer patients with all types of vision problems an opportunity to experience the benefits a hybrid contact lenses offers.

Hybrid Lenses – How they started.

The quest to develop a contact lenses that provides the opportunity for crisp vision and unparalleled comfort began in 1970 with the experimentation of placing a RGP lens on top of a soft lens known as a “piggyback system”. By using this piggyback combination, comfort was improved over RGP lenses and the quality of vision improved from soft lenses. The added benefits of good centration and increased lens stability on irregular corneas created a lens design used for the more complicated cases. The disadvantage of a “piggyback” system is the inconvenience of managing the four separate lenses. Also, on already compromised eyes the lack of oxygen and the possible adverse events of corneal swelling and blood vessel growth can be an issues with piggybacking lenses and always requires additional doctor follow up visits.  It seems reasonable if we could create a single contact lens with the advantages of both RGP and soft lenses, all the disadvantages of contact lenses would be solved. This was the first step in creating the revolutionary hybrid contact lens.

Two scientists named Erikson and Neogi had the idea that a combination lens with a hard center and soft skirt could be developed.  They patented technology that made this possible and that technology was acquired by a company called Precision Cosmet in 1977. This first “hybrid” design was known as the Saturn® lens. The idea behind this hybrid contact lens concept was to improve the performance and comfort of an RGP contact lens for irregular corneas.

In March of 1982, a pre-market investigation took place and the Saturn® lens was granted approval by the FDA in April of 1984.  With minimal customizable options and low oxygen permeability, the Saturn® lens was relegated to a problem solving lens.  Saturn lenses typically exhibited very little movement, called “tight lens syndrome” resulting in red eyes and problems of night time glare.

In 1986, a company called Sola Barnes-Hind then purchased the hybrid contact lens concept and technology and set forth to redesign the lens to address the performance issues. They named the product SoftPerm®. The SoftPerm® lens, was made out of the same material as the Saturn lens.  It had the advantage of improved comfort and additional parameters to properly fit patients. However, because the lens had low oxygen permeability and issues with the center separating from the soft skirt, the lens was still only used as a lens of last resort. A third redesign in 1989 by Sola Barnes-hind created the new SoftPerm lens but this design also suffered from its low oxygen permeability, and practitioners were still hesitant to accept it as a lens of first choice because of feared complications. Problems associated with lens sticking to the cornea and acute red eye problems further inhibited the use of these lenses.  The SoftPerm lens was discontinued in 2010.

Today, a company called SynergEyes is the only company successfully making hybrid contact lenses.

Read “Current Hybrid Lenses Technology”

Clinical Research Study – SynergEyes KC Lenses

Thursday, July 1st, 2010

Purpose: To discuss the initial results of fitting SynergEyes hybrid contact lenses (SynergEyes, Inc, Carlsbad, CA) for keratoconus (KC) and pellucid marginal degeneration (PMD).

Methods: The charts of patients fit with SynergEyes lenses during the first 7 months the lens was available on the Cornea Service at Wills Eye Institute (August 3, 2006 to March 5, 2007) were retrospectively reviewed.

Results: Sixty-one eyes (44 patients) with KC (58 eyes) or PMD (3 eyes) were fit with SynergEyes hybrid contacts. The mean age was 40 ± 12.6 years; the mean follow-up period was 7.8 ± 4.6 months. The most common indication for SynergEyes was rigid gas permeable (RGP) lens intolerance, 31 of 61 eyes (50.8%). Inability to fit with RGP was the indication in 8 eyes (13.1%), and 22 eyes (36%) were refit from SoftPerm (Ciba Vision, Corp, Duluth, GA). Twenty-two patients required refitting, including 17 base curve changes and 5 skirt changes. The success rate was 86.9% (53 of 61 eyes). Most failures (8 eyes of 6 patients) discontinued the lens within the first 1–2 months because of discomfort (5 eyes) or unsatisfactory vision (3 eyes).

Conclusion: SynergEyes lenses are a promising alternative for visual rehabilitation in patients with KC and PMD who are intolerant or unable to be fit in RGP lenses.

Key Words: keratoconus, contact lenses, SynergEyes

(Cornea 2010;29:5-8)

Rigid gas permeable (RGP) contact lenses are the standard treatment for irregular astigmatism in keratoconus (KC) and pellucid marginal degeneration (PMD). However, many patients are intolerant to these lenses because of discomfort. Other patients, especially those with very steep and/or irregular corneas, experience frequent dislocation or decentration of the lenses.1,2 In such cases, the SynergEyes lens (SynergEyes, Inc, Carlsbad, CA), a third-generation hybrid lens with a RGP center and a soft skirt, is an option to overcome these difficulties and delay the need for penetrating keratoplasty (PKP).


Received for publication June 9, 2008; revision received March 31, 2009; accepted April 10, 2009.

From the Cornea Service, Wills Eye Institute, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA.

Reprints: Elisabeth J. Cohen, MD, Cornea Service, Wills Eye Institute, 840 Walnut St, Suite 920, Philadelphia PA, 19107 (e-mail: ecohen@willseye.org).

Copyright © 2009 by Lippincott Williams & Wilkins


The Saturn II (Barnes Hind, Inc, Irvine, CA) was the first-generation hybrid contact lens produced. A number of problems existed with this lens including discomfort and corneal neovascularization,3 which were felt to be because of hypoxia associated with the low diffusion solubility (Dk) materials and a tight fit. Modifications of the original Saturn II design resulted in the second-generation hybrid lens: the SoftPerm lens (SBH, Sunnyvale, CA). These lenses had the same design and materials but a larger diameter and modified edge design to allow better tear circulation. Despite having fewer complications than the first generation of hybrid lenses, the SoftPerm lens still achieved limited success because of a high rate of giant papillary conjunctivitis (GPC), chronic hypoxia, and breakage between the RGP and the soft portions.4 In an effort to overcome the many limitations of SoftPerm contact lenses, the SynergEyes hybrid lenses were developed. These lenses have a stronger RGP/hydrogel junction and a much higher oxygen permeability of the rigid center (Dk of 100 vs 14).5 In addition, the SynergEyes contact lenses are available with 2 skirt radii for each base curve and 3 skirt radii for special KC design lenses. A good range of RGP base curves (standard 7.10–8.0 in 0.10 steps and special KC design 5.7–7.10 in 0.2 steps) and a wide range of powers [220.0 to +20.0 diopters (D)] are available. In this study, we conducted a retrospective chart review to evaluate the initial results with SynergEyes lenses in the management of KC and PMD, in a corneal and contact lens referral practice with a special interest in the treatment of corneal ectasia.

MATERIALS AND METHODS

The medical records of patients fit with the SynergEyes contact lenses on the Cornea Service at Wills Eye Institute during the first 7 months the lens was available (August 3, 2006 and March 5, 2007) were obtained through a computerized patient database search and were retrospectively reviewed. The patient data collected included sex, date of birth, ocular diagnosis, and the indication for SynergEyes fitting. The corneal topographies used for trial lens fitting, obtained using the Zeiss Atlas topographer (Carl Zeiss Meditec, Inc, Dublin, CA), were reviewed. The steep and flat keratometries (Ks), simulated Ks, and average Ks were recorded. The patients’ previous visual acuity and method of correction (whether RGP, soft contact, SoftPerm, or glasses) were noted, in addition to the most recent manifest refraction, if available.

The lens data included the base curve, skirt, and power of the initial lens dispensed; the number of refits and reorders during the follow-up period; and the final base curve, skirt, and power of the lens at the last follow-up. When the base curve and/or skirt was changed, the direction of change was noted (flatter or steeper). The initial base curve and skirt of trial lens were selected on the basis of the corneal topography, starting on the flat K for the base curve of the RGP portion, and using a steep skirt if there was inferior steepening. Because of previous experience with hybrid lenses in patients with KC, the goal was to fit a relatively flat lens without significant inferior edge lift, to avoid tight fitting lenses.

The outcome data included the best visual acuity with the SynergEyes contact lens and the need for power adjustment and over refraction, duration of lens use, and temporary or permanent lens discontinuation. The reason for discontinuation was noted and analyzed. Subjective complaints included discomfort, visual problems, and issues related to lens handling. Objective complications included GPC, superficial punctate keratitis, dry eye syndrome (DES), corneal epithelial defects or abrasions, pannus or neovascularization, corneal edema, corneal ulcers, and broken or torn contact lenses. Management and outcome of complications were also reviewed.

RESULTS

The charts of 44 patients (61 eyes) were reviewed, and included 26 males and 18 females, with an age range of 19–62 years (mean age 40.1 6 12 years). Twenty-seven patients had 1 eye fit and 17 had bilateral fitting. The bilateral cases were often those who wore SoftPerm lenses previously. The ocular diagnosis was KC in 58 eyes; only 3 eyes had PMD. The average follow-up for these patients was 7.86 4.6 months (range from 1 to 17 months).

Indications for the SynergEyes contact lens were RGP lens intolerance in 31 eyes (50.8%), inability to fit with RGP lenses in 8 eyes (13.1%), and conversion from SoftPerm in 22 eyes (36%). The mean logarithm of the minimum angle of resolution visual acuity with correction before the SynergEyes fit was 0.46 6 0.42 (range 0–2), which is approximately 20/60 (range 20/20 to counting fingers at 2 feet). The disease severity was variable, with steep Ks by topography ranging from 47 to 77 D. Two eyes had very irregular poor quality topographies so the Ks could not be analyzed. The mean steep K was 56.8 6 6.1 D (corresponding to a radius of curvature of 5.95 mm). The mean flat K was 45.7 6 6.7 (corresponding to a radius of curvature of 7.37 mm).



Figure 1

Figure 1. Relation of final SynergEyes base curve (Syn) and flat K (F1.K).



The mean final SynergEyes base curve was 7.67 6 0.34 mm (range 6.7–8.2 mm). The final SynergEyes base curve was usually flatter than the flat K (36 of 61 eyes, 59%), and the base curvewas equal to flat K in 6 eyes (9.8%) (Fig. 1). Seventeen eyes (27.8%) were fit flatter than steep (Fig. 2). The steep skirt was used for 45 eyes (73.8%), and the flat skirt was fit in 16 of the eyes (26.2%). Most of the patients wore the contacts for 10–12 hours. Visual acuity was excellent (20/20 to 20/25) in 19 of 61 eyes (31.1%) and very good (20/30 to 20/40) in 38 eyes (62.3%). Three eyes had visual acuity of 20/50 to 20/100, and 1 eye with a visual acuity of 20/200 discontinued the lens. The mean best logarithm of the minimum angle of resolution visual acuity with the contact lens was 0.22 6 0.18 (range 0–1), which corresponds to 20/32 (range 20/20 to 20/200). The lens visual acuity with SynergEyes was better or equal to that obtained with the previous correction in most of the cases (52 of 61 eyes, 85.2%). However, some patients (9 of 61 eyes, 14.8%) had better vision with their previous correction, 3 of whom stopped the SynergEyes contact lens.

Refits were necessary in 22 eyes (36.1%), including base curve changes in 17 eyes (27.9%), evenly divided between tighter (9) and looser (8) fits. Five eyes had changes in the hydrogel skirt only. Thirteen eyes had power changes. Two or 3 refits were necessary in 13 eyes (21.3%) throughout the course of follow-up.



Figure 2

Figure 2. Relation between final SynergEyes fit (Syn) and the steep K (St. K).



Complications occurred in almost one third of the eyes (19 of 61 eyes, 31.1%). The most common were GPC and allergies in 7 eyes (11.5%). These patients were treated with topical mast cell stabilizers and/or antihistamines. DES was diagnosed in 5 eyes (3 patients). A corneal abrasion occurred in 1 eye over a scar, but the patient was able to resume the contact after healing and use of ointment at bedtime. One corneal ulcer less than 1 mm in diameter with surrounding edema and neovascularization occurred in a patient with atopy. This responded to intensive topical antibiotic treatment. The patient resumed lens use but decreased the wear time from 15 to 16 hours per day to 10 hours. Two contact lenses developed tears in the hydrogel portion and not the RGP/hydrogel junction (Table 1). Four of the eyes with complications were refit with looser base curves, including 2 with DES and 2 with worsening allergies. One eye with GPC was refit with a looser skirt.

The most common complaint was discomfort, occurring in 16 eyes (26.2%), resulting in the stoppage of the contact in 5 eyes and accounting for (5 of 8 eyes) 62.5% of the failures. Interestingly, 1 patient decided to resume SoftPerm lenses because it came in a looser base curve (8.1) and then returned to be refit with the SynergEyes when the company provided lenses with the looser parameters (Table 2).

Failures occurred in only 8 of 61 eyes (13.1%) of 7 patients; lens discontinuation was early in 5 patients (1–2 months). The reason for failure was discomfort in 5 eyes. Two patients underwent PKP and 1 is considering PKP; 1 eye went back to RGP’s and 1 resumed SoftPerm lenses temporarily. Unsatisfactory vision was the cause of failure in 3 eyes, 2 of whom returned to RGP. One remained without correction because it was the same as with the contact lens (20/40) because of a traumatic cataract in this eye and had a PKP in the other eye (Table 3).

DISCUSSION



Table 1

Table 1. Complications of the SynergEyes Lens



Our initial experience with the SynergEyes lenses has been very positive with a success rate of 86.9%. These lenses have an important role in visual correction in many patients with KC or PMD who have failed RGP lenses because of poor fit or discomfort and would otherwise require surgery. In addition, patients are very enthusiastic about these lenses and often comment that they have changed their lives for the better. Patients often request to have their other eye fit with a SynergEyes. Because of the problems of dry eyes and allergies that have occurred in some patients and were also reported in the previous generations of hybrid lenses, we prefer to wait 3–6 months before fitting the second eye, unless the patient is already using SoftPerm bilaterally. We advise patients to lubricate their eyes regularly when wearing the contacts, to treat any allergies chronically, and limit their lens wearing time to 12–14 hours per day.



Table 2

Table 2. Complaints and Their Outcome



Second-generation hybrid lenses, SoftPerm, offered a reasonable alternative to RGP lenses when they became intolerable or difficult to fit, but they still achieved limited success. Chung et al6 reported breakage of the lens at the RGP/hydrogel junction as the most common complication (48.5% of cases). In this study, only 2 patients (3.2%) reported torn contacts. This is because of the differences in lens design, with an improved RGP/hydrogel junction (Table 4).5

The major shortcoming of the SoftPerm lenses was the chronic hypoxia resulting from the low oxygen permeability of both the rigid center and the soft skirt, which gave rise to high incidence of neovascularization and pannus formation (27.3% in Chung’s study).6 The SynergEyes design with the high oxygen permeability has resulted in a very low rate of the chronic hypoxia and subsequent neovascularization and pannus formation, at least during the relatively short-term follow-up. Only 1 eye of 61 in our study (1.6%) developed neovascularization and that was in a patient who overwore the lens 18 hours per day and developed a small presumed bacterial corneal ulcer.



Table 3

Table 3. Reasons for Discontinuation of SynergEyes Contact Lenses and Further Management



Discomfort, probably because of hypoxia was also reported by Chung et al6 to be a major issue with SoftPerm lenses occurring in 40% of the cases, accounting for 82% of the failures. Discomfort was less common in our patients in this series (16 of 61 eyes, 26.2%) and most patients (11 of 16, 68.7%) resumed lenses wear successfully.



Table 4

Table 4. Contact Lens Parameters for -3.00 D SoftPerm and SynergEyes Contact Lenses



Another complication of SoftPerm contact lenses was the high incidence of GPC, which occurred in 27.3% of the cases in Chung’s study.6 In our study with the SynergEyes, it only occurred in 11% of the cases (7 of 61 eyes). This is close to the rate in conventional soft contacts (10%), yet higher than that for RGP lenses, which is less than 5%.7 Patients with KC often have allergies.8 Lenses with a hydrogel component that are only replaced every 6 months are likely to aggravate allergies. This can be managed with regular enzymatic cleaning using a hydrogen peroxide system and with the chronic use of topical mast cell stabilizers/antihistamine drops (before and after lens use.)

Cohen et al9 reported 3 cases of Acanthamoeba keratitis in SoftPerm users, 1 requiring therapeutic keratoplasty, accounting for one third of Acanthamoeba keratitis in that series of contact lens–related corneal ulcers. Also Mah- Sadorra et al10 reported 1 case of Acanthamoeba associated with SoftPerm lenses in a more recent study. On the other hand, Maguen et al,4 Binder et al,11 and Chung et al6 reported no infectious keratitis with SoftPerms. None of our recent cases of Acanthamoeba keratitis (44 cases 2004–2007) were associated with hybrid lenses.12 We recommend disinfection with H2O2 systems such as Ultracare (AMO, Inc, Santa Ana, CA) and Clear care (Ciba Vision, Corp, Duluth, GA) because of their reported improved efficacy against Acanthamoeba compared with multipurpose solutions.13

The SynergEyes lenses are a major advance in the management of KC. Anecdotally, they improve the quality of lives in patients who have previously failed RGP lenses. Further studies on contact lens–related quality of life issues in KC are currently underway. We consider RGP lenses the gold standard for patients with KC because they provide excellent vision and have the best safety record. However, SynergEyes lenses enable many RGP failures to avoid surgery, including patients with mild to moderate disease who have discomfort with RGP lenses and those with advanced disease, without central scarring, who cannot be successfully fit with RGP. We recommend that patients with KC who are RGP failures be refit with SynergEyes before recommending surgery.

REFERENCES

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2. Asbell PA, Dunn MJ. Fitting the abnormal cornea. In: Krachmer JH, Mannis MJ, Holland EJ, eds. Cornea: Diagnosis and Management. St Louis, MO: Mosby-Year Book Inc; 1997:1457–1460.

3. Maguen E, Martinez M, Rosner IR, et al. The use of Saturn lenses in keratoconus. CLAO J. 1991;17:41–43.

4. Maguen E, Caroline P, Rosner IR, et al. The use of the SoftPerm for the correction of irregular astigmatism. CLAO J. 1992;18:173–176.

5. Pilskalns B, Fink BA, Hill RM. Oxygen demands with hybrid contact lenses. Optom Vis Sci. 2007;4:334–342.

6. Chung CW, Santim R, HengW, et al. Use of SoftPerm contact lenses when rigid gas permeable lenses fail. CLAO J. 2001;27:202–208.

7. Keech PM, Ichikawa L, Barlow W. A prospective study of contact lens complications in a managed care setting. Optom Vis Sci. 1996;73: 653–658.

8. Bawazeer AM, Hodge WG, Lorimer B. Atopy and keratoconus: a multivariate analysis. Br J Ophthalmol. 2000;84:834–836.

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10. Mah-Sadorra JH, Yavuz SG, Najjar DM, et al. Trends in contact lens related corneal ulcers. Cornea. 2005;24:51–58.

11. Binder PS, Kopecky L. Fitting the SoftPerm contact lens after keratoplasty. CLAO J. 1992;18:170–172.

12. Thebatiphat N, Hammersmith KM, Rocha FN, et al. Acanthamoeba keratitis a parasite on the rise. Cornea. 2007;26:701–706.

13. Hiti K,Walochnik J, Haller-Schober EM, et al. Viability of Acanthamoeba after exposure to a multipurpose disinfecting contact lens solution and two hydrogen peroxide systems. Br J Ophthalmol. 2002;86:144–146.

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