WHAT IS KERATOCONUS? ... WHAT TREATMENT OPTIONS DO I HAVE?
Quality Treatment for Keratoconus
in Bellmore, New York
WHAT IS KERATOCONUS?
Keratoconus is a non-inflammatory thinning of the cornea that causes it to bulge into a cone-like shape. This distortion of the natural shape results in blurry vision, usually from a combination of increasing nearsightedness (myopia) and something called irregular astigmatism. It is this irregular astigmatism that causes the largest visual difficulties in correcting the vision in a keratoconic patient. It is also why the above It is also why the above hard contact lens options in Bellmore, New York, are so effective and potentially life changing.
When a rigid lens of any type is placed on the cornea, it immediately corrects the shape distortion of the keratoconus by providing a smooth, regular and optically flawless surface to the keratoconic cornea. Since most of the structures of the eye other than the cornea are normal and healthy, the resulting vision is usually excellent. Keratoconus is variable in its progression and one eye is almost always significantly worse than the other. Some people hardly change over time and about 10% progress to corneal transplant or some other corneal surgery with an eye doctor, such as Intacs or ICL, to save the cornea.
In recent years another treatment has proven effective in slowing progression in those that are changing rapidly. Collagen crosslinking (CXL) is a treatment where the outer layer of the cornea is removed and a solution containing Vitamin B2 is applied to the surface of the eye. An ultraviolet (UV) light is then shown on the cornea. This results in a strengthening and stiffening of the corneal collagen and a slowing of the corneal thinning. It is important to note that none of these surgical treatments are effective at correcting vision and are more aimed at controlling the disease. Contact lenses are almost always necessary to reach your ultimate visual potential. Usually by middle age, keratoconus gets more stable and large changes later in life are unusual.
WHY SCLERAL LENSES?
Scleral lenses may be used to improve vision and reduce pain and light sensitivity for people suffering from a growing number of disorders or injuries to the eye, such as severe dry eye syndrome, microphthalmia, keratoconus, corneal ectasia, Stevens–Johnson syndrome, Sjögren's syndrome, aniridia, neurotrophic keratitis, complications post-LASIK, higher order aberrations of the eye (HOA), complications post-corneal transplant and pellucid marginal degeneration (PMD). Injuries to the eye such as surgical complications, distorted corneal implants, as well as chemical and burn injuries also may be treated by the use of scleral lenses.
Scleral prosthetics may also be used in people with eyes that are too sensitive for other smaller corneal-type lenses, but require a more rigid lens for vision correction conditions such as high astigmatism.
Modern scleral lenses are made of a highly oxygen permeable silicone polymer. They are unique in their design in that they fit onto and are supported by the sclera, the white portion of the eye. The space between the cornea and the lens is filled with non-preserved 0.9% saline solution that Dr Scheno prescribes and is often covered by medical insurance. The liquid, which is contained in a thin (~175um) post lens reservoir, conforms to the irregularities of the deformed cornea, allowing vision to be restored comfortably.
Scleral lenses differ from corneal contact lenses in that they create a space between the cornea and the lens, which is filled with fluid. The prosthetic application of the lenses is to cover or "bandage" the ocular surface, providing a therapeutic environment for managing severe ocular surface disease. The outward bulge of scleral lenses and the liquid-filled space between the cornea and the lens also conforms to irregular corneas and may neutralize corneal surface irregularities
Scleral lenses may be inserted into the eye directly from the fingers, from a hand held plunger, or from a stationary lighted plunger on a stand. Prior to inserting the scleral, the lens is over-filled with a sterile saline or other prescribed solution mixture. Some fluid is allowed to drip from the lens as it is inserted in order to ensure no bubbles become trapped under the lens after it is seated on the eye. The lens can then be rotated to the correct orientation, often denoted by a mark at the "top" of the lens, with a finger. A "left" scleral lens is often marked with two dots, and a "right" is marked with one dot.
Scleral lenses can be prescribed for dry eye as well, With the fluid reservoir bathing the cornea in a saline solution bath and thus healing the cornea by protecting it from eyelid sheering forces and diluting inflamatory chemicals in the tear film.
Scleral lenses are removed using a small lens removal plunger. Lenses are then cleaned and sanitized before reinsertion. Unlike regular contact lenses, many sclerals can be stored dry when unused for longer periods of time.
The recent development of digital topographic imaging techniques have allowed some us to evaluate and correct fit with greater accuracy. A number of scleral manufactures have also made scleral lenses with customizable points of adjustment available, so that each lens can be adjusted via a lathe to better match the contours of a single eye.
In 2010, a new digital process (KeratoCAD) for manufacturing custom contoured scleral lenses was developed. This new technology uses a digital imaging device to record the shape of the surface of an eye. A virtual 3D scleral lens design is created from the information obtained. Wavefront guided and other custom optics are then imported and incorporated into the virtual lens design. The virtual design is then used manufacture a form fitted lens with extremely high end vision correction properties.
To summarize, these unique prosthetic devices are relative newcomers to our arsenal of lenses - not only for relief of the visual symptoms of keratoconus but also for use after corneal transplant, an INTACS procedure, trauma, failed LASIK and other situations that can result in an irregularly shaped cornea. They actually rest on the white of the eye (which is called the sclera) and jump over or "vault" the cornea. This means that a scleral lens [which is fit using our own proprietary KeratoCAD® computer aided design (CAD) software program] is designed to have absolutely no corneal contact. In addition, since they have a large diameter, the edges of the lens remain under the lid allowing the lids to smoothly glide over the lens surface and not bump into the lens edge when blinking, it offers unparalleled comfort.
Many people believe that soft contact lenses are so comfortable because they are soft. This is not so. They are comfortable because they are big. If we could make a soft lens the same size as a traditional RGP lens it would be just as uncomfortable. Not only are scleral lenses large but since they do not touch the cornea, they are usually even more comfortable that a soft lens! Even if you have failed previously with contact lenses for keratoconus or another corneal disorder these lenses are quite different. We currently have about a 90% success rate with our KeratoCAD® scleral lenses.
A hybrid contact lens is a specialized contact lens that may be an option for you if you are uncomfortable wearing rigid gas-permeable contact lenses. Hybrid contact lenses attempt to give people the visual acuity of a rigid gas permeable lens with the comfort of a soft contact lens. A hybrid contact lens is comprised of a center rigid gas permeable contact lens with an outer skirt made of a soft lens material.
Hybrid contacts aren't for everyone. Some people may benefit from a hybrid lens design. Read the following list and determine if you are a candidate for hybrid contact lenses.
Do you desire a crisper, vision correction? Are you unhappy with your vision corrected by regular soft contact lenses?
Do you have high amounts of astigmatism?
If you have high amounts of astigmatism, do you want to wear a bifocal contact lens?
Do you suffer from keratoconus?
Have you had corneal trauma or a corneal transplant and suffer from corneal distortion?
Have you had refractive surgery and are unhappy with the outcome?
People with some of the problems mentioned above have some type of corneal irregularity or distortion. Many times this problem is not correctable with eyeglasses and doctors will try fitting a regular rigid gas permeable contact lens. A hard lens produces better vision because it masks all of the corneal distortions, mimicking a new smooth optical surface to focus light.
Because a soft contact lens is soft, the astigmatism or distortion often is not corrected because the soft lens just drapes over the cornea. Because a rigid gas permeable lens is hard, it is not comfortable for all people. Some people have so much distortion that it is difficult to get the lens to center properly over the cornea and pupil.
With a hybrid contact lens design, the crisp optics of a hard lens is provided with the center rigid lens. The rigid lens vaults the cornea so it is not rubbing up against it, causing discomfort. The soft skirt holds the rigid lens in place avoiding this decentration.
If you can wear a regular soft contact lens, then you can probably wear a hybrid lens. However, you may not see much of a benefit unless you have one of the conditions mentioned above. Patients that wear hybrid lenses state that their vision is much sharper than when corrected with a soft lens. Occasionally, a hybrid lens will not work. This sometimes occurs when a person has lenticular astigmatism (AKA astigmatism of the internal lens of the eye) instead of corneal astigmatism. Dr. Scheno will conduct several tests to determine if a hybrid lens will work for you.
Some people assume that hybrid lenses require more time for care and cleaning. Most hybrid lenses are just as easy to care for as regular soft contact lenses. Sometimes, the same type of solutions may be used. However, one item that you must pay particular attention to is the center portion of the lens. Because the center part is rigid, it can be broken if too much pressure is applied to it while rubbing or cleaning the lens.
In summary, these lenses truly bring the best of both worlds - The comfort of a soft lens with the crisp clarity of a hard lens. Hybrid lenses are a great choice for newly diagnosed patients and those who have had a poor experience with hard lenses in the past. They look, handle, feel and are cared for much like regular soft contact lenses. For many patients they offer the most direct route to crisp vision and all day comfort.
Tradtional Rigid Gas Permeable (RGP) Lenses
In certain situations, such as lesions on the sclera or scleral scarring, the best option is sometimes a corneal rigid lens. RGP corneal lenses can be quite effective and were the mainstay of keratoconus treatment for over 75 years. It is also a very low cost option that works very well. While not used often these days, in the right circumstances it can be a great option.
True hard contact lenses made of polymethylmethacrylate (PMMA), were introduced in the 1930’s. Considered innovative and technologically advanced for the time, these hard lenses were nearly rendered obsolete by soft lenses that debuted in the early 70’s.Roughly a decade later, rigid gas permeable lenses appeared on the scene. For clarification, vision specialists refer to these contacts by several names: gas permeable (GP) or Rigid Gas Permeables (RGP’s). RGP’s are constructed of fluorosilicone acrylate. There are several reasons why RGP’s may be the right choice for some patients, including:
Ability to diffuse oxygen (unlike hard lenses)
Less likely to transmit infection
Unlike soft lenses RGP’s retain shape and do not dehydrate
Custom made for each patient
It is easy for people with healthy eyes to take vision for granted, but the human eye is a remarkable organ. The makeup of the human eye and the series of natural occurrences within it, that allow a human being to see clearly, is at the very least, astounding. For instance, the cornea’s surface is clear and contains absolutely no blood vessels. It is unlike any other tissue in the human body that utilizes blood vessels for nourishment and protection. Gas permeable contact lenses, allow oxygen to flow to the eye and assist the cornea in defending the eye from infection and disease; protecting overall eye health.
The overall health of the cornea is extremely important. The cornea or the window of the eye, in a combined effort with the sclera (white part of the eye), lashes and tears protect the internal eye from debris and germs. The five layers of the cornea must remain clear without any opacity. Oxygen is essential in the process and is necessary to keep the cornea healthy so that it may in turn, protect the rest of the eye.
The surface of a gas permeable lens is more resistant to deposits than soft lenses. In contrast, rigid gas permeable lenses are less sponge-like and will not soak up substances that can house bacteria. GP lenses are more durable than soft lenses and because they are obviously harder, they retain better shape.Gas permeable contact lenses play an important role, allowing the proper interaction of the eye with oxygen from the air. The cornea draws oxygen from the air as tears act as a dissolving agent. The tears dissolve the oxygen from the air and transport it through the cornea, mimicking the job of blood vessels in other parts of the body. A second gas, carbon dioxide, is a byproduct of the process and is eliminated by the cornea. Interruption of this complex process makes the eye vulnerable to maladies such as corneal scarring, loss of transparency, blood vessels, and corneal warping.
Initially, gas permeable lenses take a little more getting used to than soft lenses. Within a short amount of time, however, the eyes become accustomed to wearing rigid lenses. Whereas the adaptability to soft lenses is almost immediate, it could take up to a week or two before patients find gas permeables as comfortable.
In certain situations, such as lesions on the sclera or scleral scarring, the best option is sometimes an intralimbal or large diameter corneal rigid lens. Large diameter corneal lenses can be surprisingly comfortable especially when patients are used to the feel of traditional small diameter RGP lenses. The newer more breathable and wettable materials make the RGP a great option for those seeking a visual solution to conditions like pellucid marginal degeneration (PMD) and other corneal disorders.
WHAT OTHER CONTACT LENS OPTIONS DO I HAVE?
NEW Soft Lenses for Keratoconus
Customized KeraSoft® and NovaKone® Soft Lenses
You read that correctly - The comfort of a soft lens with clearer vision than traditional contacts can offer. We are a certified KeraSoft® and NovaKone® location and can fit these amazing new soft semiscleral lenses that are a great choice for any patient but especially newly diagnosed patients and those who have had a poor experience with hard lenses in the past and would like to try a soft lens experience again that gives vision very close to a rigid lens. They provide excellent comfort and amazingly good visual acuity in the right patient.
In addition to all of the above there are countless lens designs and custom lens options available to patients today. Call for a FREE consultation at 516.409.2020 to see which are best for your specific situation and condition.