FAQ for Keratoconus and Scleral Lenses
I Have Keratoconus And Wear Soft Lenses To Correct My Vision. My Vision Is Blurred With Soft Lenses But My Doctor Feels That It Is The Best Vision He Can Give Me. Why Will A Scleral Lens Provide Me With Clearer Vision?
Your comments are all too common. There are several issues that must be considered when treating an eye with keratoconus or suffering the effects of refractive eye surgery such as LASIK:
- 1. Almost all of these corneas/eyes are very dry. A soft lens will act as a sponge and “suck” moisture from the dry cornea. For this reason, keratoconus patients wearing a soft lens may experience clear vision for a short period of time, but as the lens dries out, the lens will rotate and the vision will deteriorate relatively rapidly.
- 2. All of the corneas with keratoconus have irregular surfaces and curveatures. A soft lens lies on top of the cornea and assumes the same curevature as the cornea. In other words, the visual error of the distorted cornea is passed on through the soft lens.
I have an advanced case of Keratoconus. What instrumentation can help me understand how my lenses fit?
This is an OCT image of the gas permeable scleral lens over a keratoconic cornea. The two curved lines represent the
front and back surfaces of the scleral lens. The structure below the lens is the cornea. The space between the back surface of the lens and the cornea is filled with unpreserved saline. The lens is not touching the cornea and the compromised corneal tissue
is free to heal.
My keratoconus is very advanced. I see well with my contact lenses but they are not comfortable and pop out 6 or more times a day. I can only wear them for a few hours at a time because they hurt. My doctor says that this is the best fit that I can get. Can scleral lenses help me?
Your doctor’s response is not unusual. Many doctors associate scleral lenses with the poorly tolerated scleral lenses that were used 50 or 60 years ago. The gas permeable scleral lenses used today are made of a highly oxygen permeablematerial that provide excellent vision and comfort. In fact, patients with a number of corneal diseases actually undergo a healing effect after scleral lens wear. The liquid reservoir that exists between the back surface of the lens and the front surface of the cornea bathes the corneal surface while the lenses are worn. This reduces the pain and light sensitivity that can be debilitating to patients with corneal diseases such as keratoconus, Stevens-Johnson Syndrome, post-LASIK and post-R-K surgical complications, corneal transplant surgery complications, chronic dry eye and so on.
I Have An Advanced Case Of Keratoconus. Why Can’t I Get Eyeglasses That I Can See With?
Patients with keratoconus have distorted corneas. Your cornea acts in much the same way like the windshield of your car. If the
windshield of your car is distorted or misshapen, your view of the world beyond the windshield will be distorted, regardless of what kind of eyeglasses you are wearing. Patients with advanced keratoconus or other forms of irregular corneas should think of eyeglasses solely for the purpose of maneuvering about their home or for emergencies. What is really unique about the GVR Scleral lens is that the irregular, distorted cornea is replaced by a smooth, regular optical surface. No matter how distorted or irregular the cornea is, assuming that the interior structures of the eye are healthy, the blurred, distorted vision will be corrected. Almost all of our patients with advanced keratoconus who are legally blind (20/200 or less vision) with their old contact lenses or eyeglasses have 20/20 vision with the GVR Scleral lenses.
What Is The Difference Between Keratoconus And Corneal Ectasia Following LASIK Surgery?
Corneal Ectasia is one of the most devastating complications resulting from LASIK. It has been my experience that this condition develops weeks to years following LASIK surgery. When this develops, patients will notice a rapid onset of blurred, distorted vision which cannot be corrected with eyeglasses or conventional contact lenses. There is no way to determine (with absolute certainty) beforehand whether a patient is at risk for corneal ectasia after LASIK. I have found that the most effective way to treat this LASIK induced complication is with a GVR Scleral lens.
Keratoconus is a protrusion or ectasia of the cornea due to heredity. While the end result of keratoconus, visually may be the same as in post-LASIK corneal ectasia, the treatment may differ. With post-LASIK corneal ectasia, we are usually dealing with a very dry cornea and a LASIK created corneal flap. This type of cornea does not do well with a soft or conventional gas permeable lens. The reason for this is that most of the time these corneas cannot tolerate of support any type of lens (rigid or soft) resting on it’s surface. I prefer to use a GVR Scleral lens because this unique lens will not rest of the post-LASIK cornea but will vault over the compromised corneal tissue. A liquid reservoir exists between the back surface of the lens and the front surface of the cornea. In other words, the traumatized cornea is always in a moist environment. Besides restoring quality vision and comfort, the lens acts as a therapeutic device and promotes healing.
With keratoconus, the cornea, while distorted, may not be as dry as the post-LASIK cornea. In addition, there is no LASIK created corneal flap to contend with. For this reason among others, there are a number of specialty soft and gas permeable lenses that may work well on a keratoconic cornea that will not provide quality vision or comfort or promote health to the post-LASIK traumatized cornea with ectasia.
1. Why should I consider a scleral lens and not just go ahead with a corneal transplant?
There are real risks involved with corneal transplant surgery including infection and rejection of the transplant. In addition, long term studies of patients with corneal transplants have shown the following to be true:
- 50% of patients who underwent corneal transplant surgery will need some form of rigid contact or scleral lens in order to achieve visual acuity better than 20/50.
- Stable vision in most cases is not achieved for one year or longer after the surgery.
- In many cases the life time of the corneal graft is limited. Repeated corneal transplant surgery (due to infection, rejection etc.) is the 2nd commonest indication for a repeated corneal transplant operation.
- There is a life long risk of rejection. This risk is greater in younger patients.
- There is a life long risk of wound rupture due to trauma.
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