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Posts Tagged ‘keratoconus treatment options’

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.

I’ve Just Been Diagnosed With Keratoconus

Sunday, August 1st, 2010

By: David Kading, OD, FCLSA, FAAO

If you have just been diagnosed with keratoconus, let me first of all reassure you that there have been many recent advancements in the realm of keratoconus to equip eye care professionals with the proper tools to help you.

Keratoconus is a vision disorder that affects the front surface (cornea) of the eye.  The changes that take place occur because the cornea becomes thinner in certain areas.  The condition causes the normal regularly shaped cornea to become microscopically irregular in shape.  This causes light to scatter in irregular ways causing vision to be blurry, distorted, warped, and haloed as opposed to crisp and clear.  Because glasses and normal off-the-rack contact lenses cannot help to make the surface of the eye even and regular, for most keratoconus patients, they are not able to provide ideal vision.  Additionally, lasik surgery is not an option for patients with this thinning disorder because lasik surgery thins the cornea in an effort to correct vision.  Therefore it would only make the condition worse.

Keratoconus affects thousands of Americans and people all across the world.  It is believed that there may be a genetic component to the disease as it has been seen in identical twins.  However many keratoconus patients develop the condition after a mild accident, trauma to their eye or after years of eye rubbing.  Many other patients are not able to trace the condition to a family member or any type of eye trauma.

The first thing that you should do when you are diagnosed with the condition is ensure that you are under the care of an eye care practitioner who is knowledgeable about the condition.  A knowledgeable practitioner will know, understand, and be able to decide on the best course of treatment for you.  Although many keratoconus patients appear similar when they present to an eye care office, no two patients are alike.  Each has specific needs related to the shape of their eyes and how they use their vision on a daily basis both for work and recreation.  It is critical that your practitioner knows both you and your eyes.

In order to get the best idea of what the shape of your eye is, your practitioner may consider using an instrument called a corneal topographer.  This allows them to measure the specific areas of the eye in order to get the best assessment of the shape and contours of the eye.  This is extremely helpful in order to properly diagnose, and decide on the proper treatment options.

In mild cases of keratoconus, eyeglasses can still be used to help correct vision.  However, in most all cases of the condition, proper vision correction is best achieved with the use of specially designed contact lenses.  Depending on the shape of the eye, type of prescription, and discussion with you, your eye care practitioner will decide on an initial contact lens type.  In order to get the proper contact lens for you, a contact lens fitting must be performed.  This is often times performed as a separate visit to the office.  Following this visit, the lenses will be ordered from a contact lens laboratory or manufacturing plant.  Typically contact lenses can be made in several days, but it can take up to 2 weeks in some cases for the lenses to arrive back in the office.

Once the lenses arrive in the office, an additional visit is usually scheduled to ensure that the lenses are fitting on the eyes correctly and giving the optimal vision.  At this visit you are typically instructed on how to insert and remove the contact lenses.  Many times a wearing schedule will be described to you so that you can begin to adjust to the lenses.  As with most medical devices and things that are new to our bodies, it may take several days to weeks to adjust to the comfort, vision, and feeling of the new lenses.  This is very typical in most cases.  Most offices will request a follow up visit within one to three weeks to ensure that the lenses are fitting correctly.  Make sure to wear the lenses for several hours prior to this visit as an assessment of the lenses is best done after the lenses have been worn for at least three hours.  It is critical to ensure that the fit of the lenses is correct as they can cause damage to the eye if they are incorrect.  On occasion the initial type of lens that is tried does not work.  This is not uncommon and should not cause alarm.  Fortunately as stated earlier, there are many options.  The practitioner may switch you from one type of contact lens type to another if your eyes were not able to adapt to the initial lens type.

In very severe cases when contact lenses cannot provide ideal vision, there are also surgical options available.  These surgical options are progressing and are showing improving results.  However they are not a perfect solution, they require a significant healing time and most patients still must wear specialty designed contact lenses following the procedure.

Keratoconus is a condition that will last a lifetime.  Within the past 10 years dramatic insight, knowledge, and research has come out regarding the condition, its diagnosis, and treatment options.  Find a practitioner that you can trust and is up to date with the most recent advancements.  Make sure that they know everything there is to know about your eyes and vision, but most importantly, they should know you.  This is the type of relationship that will last a lifetime.

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.

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