The shape of the cornea plays an important role in focusing light on the retina. A standard shaped cornea and a healthy, clear lens allows light to focus clearly. If the cornea becomes cloudy or if the cornea becomes irregular in shape, vision can be impaired. Modern technology has made corneal transplantation a successful procedure, allowing patients to receive clear vision through a partially or fully replaced cornea transplant surgery.
Descemet's Membrane Endothelial Keratosplaty (DMEK) is a corneal surgical procedure similar to the DSEK procedure, and it is used to treat severe cases of corneal disease or damage in the cornea. While the traditional full-thickness corneal transplant replaces a damaged cornea with a full donor cornea, the DMEK procedure replaces only the interior lining of the cornea, called the endothelium, with a donor tissue.
DSEK is a partial thickness corneal transplant that requires a thin piece of donor tissue to be placed on the back surface of the cornea. The DSEK procedure is designed for patients who have clouded corneas as a result of endothelial dysfunction. The endothelium pumps fluid from the cornea to keep the tissue clear. If these cells are not working properly, the cornea will become cloudy and will swell. Instead of transplanting the full cornea, only the diseased pump cells will be replaced.
Unlike the full thickness Penetrating Keratoplasty (PK), DSEK uses a much smaller incision resulting in a more stable wound that is less likely to open with trauma. DSEK can also reduce the risk of complications such as hemorrhaging that could threaten your vision.
What is Ectasia?
Patients who suffer from ectasia experience a bulging and protrusion of their cornea in a cone-like shape. Ectasia often occurs in keratoconus (KCN) and pellucid marginal degeneration (PMD), disorders associated with the thinning of the cornea region. Altered corneal biomechanics in these diseases not only cause the tissue to protrude at the weakest and thinnest point, but this also significantly decreases the ability to see clearly.
How does it occur?
Ectasia is a result of a genetic predisposition to a weak cornea in combination with environmental factors, the most important of which is eye rubbing. It's really important to not rub your eyes because that can cause further bulging of your cornea.
How is it treated?
In the past, patients suffering from ectasia depended on treatment options such as rigid contact lenses or penetrating corneal transplants. However, these treatment options did not halt the progression of ectasia or treat the condition at the root cause. The development of corneal collagen crosslinking by German ophthalmologist Theo Seiler 15 years ago, however, does have the potential to do so and has the ability to restore the quality of life of those who have been suffering from this condition.
How does corneal collagen cross-linking work?
Our corneas naturally contain cross-links between collagen fibers in order to maintain shape and strength. Ectasia is a result of not enough of these cross-links to support the cornea, leading to bulging and protrusion. This innovative procedure utilizes a combination of riboflavin and UV light to create additional cross-links to promote cornea stability and strength. The corneal collagen fibrils are chemically bonded together to halt the thinning process and restore vision acuity. This procedure does not involve surgical incision into the eye or ablation, as it is only minimally invasive. Clinical trials have demonstrated that the strengthening effect may be permanent.
Is corneal collagen cross-linking FDA approved?
The FDA has recently been counselled to approve corneal cross-linking. Our facility has been involved with corneal cross-linking since 2011 through participation in the clinical trials leading up to FDA approval. We are at the earliest stages of implementing this exciting technology and are eager to continue developing this new category of treatment. There is a large population of patients with ectasia that are awaiting approval in order to proceed with their crosslinking, and we are looking forward to treating them as soon as possible.
If the whole thickness of the cornea is unhealthy, a full thickness corneal transplant called a Penetrating Keratoplasty (PK) will be required. During the PK procedure a circle of corneal tissue is removed and replaced with the donor tissue. This new corneal tissue will be stitched into place for a comfortable and smooth healing process. If you are interested in discussing cornea problems with our doctors in Sioux Falls, South Dakota, please feel free to call Vance Thompson Vision directly. The Vance Thompson Vision doctors are internationally recognized for excellence in cornea transplant surgery right here in Sioux Falls, South Dakota, call Vance Thompson Vision (605) 367-EYES (3937) or (877) 522-EYES (3937).