Cornea
What is the Cornea?
The cornea is the thin, transparent, domed layer of tissue on the outer surface of the eye that covers the iris, pupil, and anterior chamber. It helps to protect your eye from germs, UV rays, and debris.
Its shape can also affect the clarity of your vision, as it is the part of the eye that helps focus light on the retina to produce clear images. If the cornea is misshapen, it can cause refractive errors like nearsightedness, farsightedness, and astigmatism.
How Does the Cornea Work?
The cornea is made up of six layers that work together to help your eye function at its best. The epithelium, or the outermost layer of the cornea, is the first line of defense to protect your eyes from injury or debris.
Underneath, Bowman’s layer and the stroma are there to strengthen the structure of your cornea. The stroma is also the structure that helps your cornea bend light into the retina to make a clear image.
Pre-Descemet’s layer is airtight and contains fluid in your eye. Descemet’s layer helps protect the inside of your eye from infection and injury.
Finally, the endothelium works to maintain the balance of fluid in your stroma so that the eye functions appropriately. All of these layers make up the cornea, a key component in bringing you clear vision.
What are Common Conditions that Affect the Cornea?
Many conditions can affect the cornea, leading to changes in vision, eye irritation, or damage:
Dry Eye
Dry eye is a common eye condition, with symptoms including excessive tearing, burning, stinging, gritty sensation, light sensitivity, redness, and blurred vision. Tear film is made up of three components (mucus, water, and oil) that are secreted from glands around the eye.
A deficiency in one of these components can cause dry eye. Treatment of dry eye varies from patient to patient and depends upon the severity of the condition.
Keratoconus
Often seen in younger patients, keratoconus is an eye condition in which the cornea thins and begins to bulge outward into a cone shape. This can lead to distorted vision, light sensitivity, double vision, irregular astigmatism, or nearsightedness.
Corneal Dystrophies
Primarily caused by genetics, corneal dystrophies are progressive eye conditions that can alter the shape of the cornea, resulting in vision problems. Fuchs’ dystrophy is the most common type of corneal dystrophy, a condition where the cells that make up the endothelium of your cornea begin to die off, causing the layer to eventually stop functioning.
Because this layer is in charge of regulating fluid levels in your cornea, when it stops working correctly, it may swell. It can cause blurry vision, blisters, pain and irritation, scarring, sensitivity to light, and difficulty seeing at night.
Other corneal dystrophies include lattice corneal dystrophy, granular corneal dystrophy, and epithelial basement membrane dystrophy.
Corneal Injuries
Corneal injuries such as abrasions and scars can cause impaired vision, eye pain, and redness. Corneal ulcers can occur due to corneal damage.
If left untreated, they can lead to corneal clouding, perforation, or significant vision loss, so early detection and treatment of corneal ulcers is crucial to preserving your sight.
How Are Corneal Conditions Treated?
Treatment for your corneal condition depends on the condition treated, as well as the level of progression or severity of the condition. Some conditions can be treated at home or quickly remedied with medicine prescribed by your eye doctor, while some may require surgical procedures performed by Dr. Newman at Rockdale Medical Center Outpatient Surgery Department:
PKP (Penetrating Keratoplasty)
PKP, or penetrating keratoplasty, is a full-thickness corneal transplant performed to treat corneal conditions such as keratoconus, injuries, swelling, and scarring. During PKP, Dr. Newman removes the damaged central portion (the button) of the cornea and replaces it with the donor cornea supplied by the local eye bank.
DSEK (Descemet’s Stripping Endothelial Keratoplasty)
Unlike PKP, DSEK (Descemet’s stripping endothelial keratoplasty) replaces the endothelium, the bottom layer of the cornea. Fewer stitches are required for this procedure, there is a lower chance of rejection, and recovery times are typically faster.
DSEK is primarily used to treat Fuchs’ corneal dystrophy.
