The cornea is the eye’s outermost layer. It is the clear, dome-shaped surface that covers the front of the eye and allows light to pass into the eye to reach the lens and the retina. The cornea also helps the eye focus light, like a camera lens. The health of the cornea depends on several factors, including the health of the conjunctiva and the eyelids.
The conjunctiva is the tissue that covers the front part of the eyeball (but not the cornea) and lines the back of the eyelids. Both the conjunctiva and the eyelids contain glands that make tear fluid, which helps maintain the health of the cornea.
A corneal ulcer is an open sore on the cornea. Corneal ulcers usually result from an eye infection, but severe dry eye or other eye disorders may also cause them. Your doctor can diagnose an ulcer by staining the surface with a fluorescein dye that will show damage under the slit lamp light. Common symptoms of a corneal ulcer include redness and pain, blurred vision, tearing, and the sensation that a foreign object is in the eye.
Corneal dystrophies are a group of rare genetic eye disorders. While some people are asymptomatic, others have a build-up of material in the cornea causing it to become opaque. This can lead to blurred vision and even vision loss. There are more than 20 different types of corneal dystrophy.
While the cornea typically heals from minor scrapes and scratches, major corneal damage can result in a corneal scar. Corneal scars can be caused by improper use of contact lenses, deep scratches, burns, and some diseases. This damage can cause the clear corneal tissue to be replaced by scar tissue, sometimes impairing your vision.
Keratoconus, often known as KC, is a non-inflammatory eye condition in which the cornea progressively thins and weakens, causing a cone-like bulge and optical irregularity of the cornea. Keratoconus can result in significant vision loss and in severe cases may lead to corneal transplant.
Early symptoms of keratoconus may begin in a person’s late teens or early twenties and may progress for 10-20 years before slowing and stabilizing. Each eye may be affected differently. In the early stages, someone with keratoconus may experience:
Keratoconus treatment generally progresses from glasses to contact lenses to corneal transplantation. A new therapeutic treatment option, Corneal cross-linking, is a minimally invasive outpatient procedure giving patients with keratoconus the first-ever therapeutic option.
A gas permeable contact lens is the most effective way to manage keratoconus and 90% of all cases can be managed this way indefinitely.
These contact lenses provide a regular surface over the cornea to neutralize the distortion brought on by the irregular cornea and can be made to fit your cornea. If the cornea becomes too scarred or painful, a corneal transplant may be necessary.
Patients over the age of 14 who have been diagnosed with progressive keratoconus or corneal bulging following refractive surgery should ask their doctor about corneal cross-linking.
Thomas Eye Group is proud to offer our patients the first and only therapeutic products for corneal cross-linking which have been FDA approved to treat progressive keratoconus.
As the cornea becomes more irregular, glasses or contacts may no longer provide adequate visual improvement and your doctor may recommend corneal transplant surgery. Corneal transplant surgery replaces the cornea with tissue from a donor.
Descemet’s Stripping with Endothelial Keratoplasty (DSEK) is a newer cornea transplant technique that replaces only the damaged cell layer instead of replacing the entire cornea. In the DSEK procedure, a thin, circular disc of donor corneal tissue is folded and placed inside of the eye where an air bubble pushes it in place until it heals in the appropriate position. No sutures are required, and the structure of the cornea remains intact. With this technique, the cornea heals much faster and stronger and the patient’s visual recovery is better. DSEK is a preferred method for treating Fuchs’ Dystrophy and pseudophakic bullous keratopathy.
The DSEK procedure is performed under local anesthesia and takes approximately 45 minutes. For the first 24 hours after surgery, you will be asked to lie on your back with your face pointed directly to the ceiling for as much time as you can tolerate. This will help the graft stay in position as the air bubble holds it up into place on your cornea. Your doctor will prescribe eye drops to prevent infection and help the eye(s) heal properly and comfortably. After the first 48 hours, there are minimal restrictions on your activities. Your vision will likely start improving within one week. One month after surgery, 80% of the healing has taken place but your vision can continue to improve over the next four to six months.
Penetrating Keratoplasty (PKP) involves replacing an eye’s scarred, diseased, or damaged cornea with clear corneal donor tissue, resulting in improved vision.
PKP is suitable for patients with corneal decomposition, corneal dystrophies (other than keratoconus) including Fuch’s Dystrophy and corneal trauma corneal scarring.
In a PKP procedure, donor corneal tissue is prepared to become the transplanted cornea. The diseased or scarred portion of the patient’s cornea is removed, and the donor cornea is gently sewn into place with ultra-fine sutures. Stitches are typically removed at one year. Vision may start to improve the day after surgery, but patients should expect a slow, gradual recovery of vision over the next six months to one year following surgery.