KERATOCONUS AND OTHER ECTASIAS (THINNING DISORDERS) OF THE CORNEA CAN CAUSE MANY DEBILITATING VISUAL AND MEDICAL ISSUES FOR PATIENTS. SCLERAL CONTACTS CAN BE A WONDERFULA SOLUTION TO THE MYRIAD ISSUES SURROUNDING KERATOCONUS (KC).

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 WHAT IS KERATOCONUS?

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Keratoconus is a non-inflammatory thinning of the cornea that causes it to bulge, because of pressure caused by aqueous humor flow inside the eye, into a cone-like shape. It affects roughly 1 in 375 people in the general population and can affect hispanic, middle eastern and african-american patients with prevalence rates as high as possibly 1 in 150. 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 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 utilizing the tear film to fill in all the hills and valleys of the irregular cornea 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, repair or replace 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.

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WHY SCLERAL CONTACTS?

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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 is prescribed such as ScleraFil or LacriPure and is sometimes even 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 to the keratoconic cornea.​

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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.

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​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 even be stored dry when unused for longer periods of time.

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As discussed in the overview, recent development of digital topographic imaging techniques have allowed some practitioners 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.

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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.

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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.

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To learn more about how scleral lenses can help you with your keratoconus/corneal issue or to make an appointment at our facility for a free scleral lens consultation you can call our toll free office line at: 

 

833.FIX.MY.KC (833.349.6952) or visit our website.

 

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