Specialty Contact Lenses

Corneal Transplant

When a patient has had a corneal transplant, the cornea usually exhibits a fairly irregular shape. Due to the irregularity the vision is often not corrected adequately with glasses or soft contact lenses. For this reason many patients who have undergone corneal transplant will require a custom contact lens. The choices we are currently using for these patients include reverse-geometry rigid gas permeable contact lenses and scleral lenses. 

Keratoconus

Definition:

Keratoconus is a condition in which the normally round dome-shaped cornea progressively thins, causing a cone-like shape to develop. This usually results in significant vision impairment. For more information please visit www.nkcf.org

 
Incidence:

Keratoconus is estimated to occur in 1 in 2000 people.

Management:

In the early stages many patient will see adequately with glasses or soft contact lenses. As the disease progresses and the cornea thins and becomes more irregular, the vision is often not adequate unless a rigid contact lens is used. The lenses must be carefully fitted and monitored. Because the cornea continues to change shape, the lenses may need to be re-fitted in one to two years. It is important to have the fit evaluated yearly for any needed changes.

Dr. Kaufman’s pearls about contact lens fitting for keratoconus:

Keratoconic corneas all have a unique shape. Because these shapes are irregular, the lenses must be custom designed and manufactured for each eye. Trying sample lenses on the eye during the fitting process speeds things up considerably. We carry many fitting sets in stock and can borrow fitting sets from our laboratory when we need additional options.   Lenses we consider for keratoconus include rigid lenses such as RoseK, scleral lenses such as Jupiter and Maxim, and hybrid lenses (rigid lens with a soft skirt).  We have been having great success with scleral lenses due to increased patient comfort versus conventional sized rigid lenses.

LASIK

Some patient experience regression or even corneal irregularities after LASIK. Because LASIK removes some of the tissue from the cornea, these eyes can be a bit more complicated to fit. The normally round dome-shaped cornea is now flat across the top and may no longer do well with a round dome-shaped contact lens draped across the front of the eye. In these cases we use specialty contact lenses such as reverse-geometry RGPs or scleral lenses. 

R.K. (Radial Keratotomy)

Some patient experience regression or even corneal irregularities after R.K.. Because R.K. cuts flatten the top of the normally dome-shaped cornea, these eyes can be a bit more complicated to fit.   A dome shaped lens (traditional standard contact lens) will often not fit well, and a custom contact lens will be necessary. In these cases we use specialty contact lenses such as reverse-geometry RGPs or scleral lenses. 

Astigmatism

Many patients with astigmatism will not need specialty contact lenses and will often be fit in a toric disposable contact lens.   Patients who want as crisp and consistent vision as possible vision may be happier in a Duette contact lens or a rigid gas permeable lens. Patients with high amounts of astigmatism will often not do well with a soft contact lens and would do well with a custom bitoric rigid gas permeable lens.

Dry Eyes

Some dry eye patients may not be ideal candidates for contact lenses. But some causes of dry eye are actually treated with scleral contact lenses which help maintain a reservoir of moisture against the cornea. If you have dry eyes we recommend having a Dry Eye Consultation with Dr. Jensen. At that visit he will discuss the best treatment options for your eyes.

Corneal Reshaping

Corneal reshaping involves using a rigid gas permeable contact lens designed to temporarily correct myopia (nearsightedness) by gently and reversibly reshaping your cornea while you sleep. You may then be able to go throughout the day without any lenses. The reshaping lenses are made from an overnight contact lens material in a special design intended for this purpose. These can be a great way to slow down the myopia progression in some children. At our office we use Paragon CRT lenses for this purpose. Please see www.paragoncrt.com for more information.

Rigid Gas Permeable Contact Lenses (RGPs)

These lenses are smaller than the cornea. They are made of highly oxygen permeable material.   RGP is a broad category of contact lenses which can be custom-designed to meet the needs of many different eyes. RGP material usually gives superior vision to a non-spherical eye versus a soft contact lens alternative. The reason for this is that the material is rigid and provides a new spherical refracting surface for images to enter the eye. RoseK, reverse geometry, bitoric, etc. are simply designs for particular corneas. Side note-- RGPs have been shown in some studies to slow down the progression of myopia in young people.

Scleral Contact Lenses

These are large diameter rigid gas permeable lenses that rest on the white part of the eye, called the sclera, and vaults over the cornea. The size can be an alarming prospect for some, but scleral lenses have many advantages. Because of their size, they do not fall out and dust or dirt particles cannot get under them during wear. They are surprisingly comfortable to wear, because the edges of the lens rests above and below the eye lid margins so there is no lens awareness.  For more information please visit www.sclerallens.org

Hybrid Contact Lenses

Hybrid contact lenses are a rigid gas permeable contact lens with a soft skirt. The soft skirt can increase comfort and help with centration. This category currently has only one manufacturer, Synergeyes. Synergeyes has recently released the Duette contact lens. Duette is an improvement in the prior design in that the soft skirt is now much more oxygen permeable and therefore should have less risk of complications. We are one of the first practices in the area to be fitting the Duette contact lens and we are eagerly awaiting the version of this lens intended for irregular corneas.

Prosthetic Contact Lenses

Prothstetic contact lenses may be soft or a rigid scleral lens. They are most often used in patients with scarred corneas or patients with no iris. These lenses have an iris (the colored part of the eye) painted on the front.   These lenses can be made with a blocked pupil for patients with non-seeing eyes to cover a scar for aesthetic reasons. They can also be made with a clear pupil for sighted patients and can greatly improve cosmesis. For patients with aniridia (no iris) the lenses help block peripheral light rays—greatly increasing patient comfort.