Specialty Contact Fittings
What Are Specialty Contact Lenses? Who wears them and why?
While many of us enjoy wearing standard prescription eyewear, some patients find out from their a local optometrist in Hoffman Estates that they have an eye condition that will prevent them from wearing standard contact lenses and, in certain cases, even basic eyeglasses. The news about one's eyesight can be heartbreaking, especially since our vision provides such basic, fundamental needs in our lives. Fortunately, our practice is one of the leaders in providing eye care solutions for even eye diseases like keratoconus.
At our <strong>eye care facility in Hoffman Estates,</strong> we've met countless of people who struggle with various vision problems, where either we'll help with LASIK surgery to correct the problem, but in other cases, specialty contact lenses are recommended.
Specialty contact lenses are used to treat a variety of conditions that are most often associated with an unhealthy cornea. To ensure amazing comfort, visual acuity, and, most importantly, zero interference with the cornea, our contact lens specialists at Sullivan-Ostoich Eye Center utilize advanced, custom contact lenses like scleral lenses
Keratoconus is a non-inflammatory eye condition where the normally round dome-shaped cornea progressively steepens, causing a cone-like bulge. The result is significant visual impairment. The cornea is the "windshield" of the eye. It is responsible for refracting most of the light coming into the eye. Therefore, abnormalities of the cornea can severely affect the way we see the world.
It can make simple tasks like watching TV, driving and reading a book very difficult. In the early stages of keratoconus, a person may experience slight distortion and blurring of vision along with increased sensitivity to light and glare. Symptoms are usually first seen in the persons late teens to mid-twenties. Keratoconus is a progressive disease and can affect one person more or less than another. Each eye can be affected differently.
In the early stages, eyeglasses or soft contact lenses can be used to correct for the mild nearsightedness and astigmatism. As the disorder progresses, the cornea will continue to thin and change shape. Gas permeable lenses will be needed to correct vision more adequately.
In severe cases, patients may become contact lens intolerant or not be able to achieve the vision needed to perform daily tasks. At this point, a corneal transplant may be needed where the cornea is replaced with a healthy donor tissue.
Methods of Correction
Keratoconus is managed with many different contact lens designs. There is no one design that is best for every patient. Since each lens design has its own unique characteristics, the practitioner will need to evaluate each patient needs to determine the lens that would offer the best combination of visual acuity, comfort, and corneal health.
In the early stages a person can be corrected with glasses or soft contacts lenses but as the disorder progresses it becomes difficult to correct vision caused by the irregular corneal surface. At this point, more complex contact lens designs will be needed.
The role of soft lenses in keratoconus is limited because the soft lens drapes over the irregular corneal surface. Therefore, the front surface of the lens assumes the same irregular surface as the cornea without trapping a fluid reservoir so the effective refracting surface shows no improvement over the original corneal surface. There are some specially designed soft lenses that are thicker and retain more of a rigid shape and may contribute to the liquid lens affect to some extent. These soft lenses are generally only used in mild to moderate cases of keratoconus.
Rigid Gas Permeable lenses (Rose K, Rose K2, Rose K2 IC, Centracone) are the primary option for correcting keratoconus. The rigid gas permeable lens masks the underlying irregular cornea and serves as a new refractive surface of the eye. The tear film fills in space at the back of the contact and the front of the eye. As seen above, there are many RGP designs. The design is determined by the severity of the disease.
This is where an RGP lens is worn on top of a soft lens. The RGP lens provides crisp vision and the soft lens acts as a cushion providing increased comfort. With new RGP designs and materials, the "piggy-back" system is not used very often.
Hybrid lenses (Soft perm, Synergize) are lenses that have an RGP center with a soft lens skirt. The idea of this lens design is to give good vision thru the RGP lens with the comfort of a soft due to the "skirt".
We were the first practice in the United States to use the MSD Lens! These are large diameter lenses that rest on the "white" part of the eye, called the sclera. The idea of this lens is that it vaults over the cornea. The scleral lenses have many advantages. Because of their size, they do not fall out. Dust or dirt particles cannot get behind them during wear. They are surprisingly comfortable to wear because the edges of the lens rest above and below the lids giving little to no lens awareness. The key to its effectiveness is the artificial tear-filled reservoir that it maintains over the diseased cornea functions as a soothing and healing liquid eye bandage.
Scleral lenses were mentioned in lenses used under keratoconus, but they are used in many other situations also. The Mini Scleral Design allows for the creation of a smooth surface to replace the irregular corneal surface, thereby giving good stable vision and automatically correcting for most astigmatism. This lens provides excellent patient comfort and oxygen permeability to the cornea during wear.
The MSD is suitable for the majority of pathology cases ranging from advanced keratoconus to post LASIK corneas. For irregular corneas on which fitting a regular contact lens has not lead to optimal results, the MSD lens is a great option. Patients we have fit with these lenses have had:
- Severe dry eyes
- Corneal degeneration
- Post-refractive surgery (post LASIK and post-RK)
The objective of fitting this lens is to vault it over the cornea. When inserting the lens, the lens is filled with saline or artificial tears. The saline or artificial tears then stay under the lens while being worn acting as a cushion and protectant to the cornea. The rigid surface creates a new refracting surface providing excellent vision when other options are not available.
Although the lens is quite large, comfort is excellent as the lens sits under both the upper and lower lid. This lens is often called the “miracle lens” since it allows patients to have good vision when no other means of correction worked!