The cornea is the transparent, dome-shaped window on the front of your eye that covers the iris and pupil. Its main purpose is to refract light. It also contributes approximately two-thirds of the eye’s total focusing power, even though its focus is fixed. The cornea consists of three layers:
- The stroma, which makes up most of the cornea.
- The epithelium, consisting of several layers of cells covering the exterior of the stroma.
- The endothelium, which is a single layer of cells lining the interior of the stroma.
Cataracts are usually the condition that’s familiar to most people when they think of eye problems. However, cataracts technically affect not the cornea but the eye’s crystalline lens, which is just behind the pupil and works with the cornea to focus light on the retina. Regardless, the cornea is susceptible to a number of other conditions, including:
Corneal Abrasions and Recurrent Erosions
Abrasions and recurrent erosions are some of the most common conditions affecting the cornea. These are scratches or injuries on the surface layer of the eye caused by foreign objects, like sawdust or fingernails. They can be very painful and cause a number of serious issues, but often heal rapidly when appropriate care is taken.
Recurrent corneal erosions can be caused by a variety of underlying problems, including from a previous abrasion. Typically, these occur when the top layer of the cornea, the epithelium, is not tightly attached to the rest of the cornea and becomes easily peeled off in a very dry environment, such as when patients with severe dry eyes are sleeping. If the epithelium is more tightly attached to the inside of the eyelid, it may peel off when the patient wakes up and opens his or her eyes.
There are a variety of nonsurgical treatments ranging from artificial tear gels or ointments which may prevent the erosions from recurring. Surgical options may be considered when nonsurgical treatments aren’t effective.
Fuchs’ Dystrophy
Fuch’s dystrophy is a relatively common corneal condition that causes the cells in endothelium layer of the cornea to die off. These cells normally pump fluid from the cornea to keep it clear. When these cells die, fluid builds up and the cornea gets swollen and puffy. Vision often becomes cloudy or hazy.
Fuchs’ dystrophy has two stages. In stage 1, you may not notice any symptoms. Vision may be hazy in the morning but improves throughout the day. This is because your eyes normally stay lubricated when they are closed during sleep. But when your eyes are open when you’re awake, the fluid dries normally.
During the later stage 2, vision remains blurry all day because too much fluid builds up during sleep and not enough dries up during the day. In addition, tiny blisters may form in the cornea. The blisters get bigger and eventually break open, causing eye pain.
People in their 30s and 40s may have Fuchs’ dystrophy but not know it, and vision problems may not appear until age 50 or later. Women are more likely than men to develop Fuchs’ dystrophy. Because Fuch’s dystrophy leaves dots on the inside of the cornea and causes swelling of the cornea, the condition can sometimes require surgery.
Infectious Disease
Many types of bacteria, viruses, fungi, and parasites common to other infections can lead to serious eye conditions, including corneal ulcers. These conditions are serious and can lead to serious vision issues or even rapid loss of vision, particularly if left untreated or not properly treated.
Many medical conditions, including infection with bacteria and viruses, and treatment with certain drugs, can adversely affect the health of your eyes. Lyme disease, diabetes, and sexually transmitted diseases like herpes, syphilis, and HIV/Aids can affect the cornea and overall health of the eyes.
Bacterial Keratitis
Bacterial keratitis is an infection of the cornea. It usually develops quickly and can cause blindness if left untreated. There are many different bacteria that cause keratitis, but the two most commonly responsible cornea infections in the U.S. are staphylococcus aureus and pseudomonas aeruginosa.
The two main causes of bacterial keratitis are contact lens use, especially extended-wear lenses, and eye injuries. Wearing contact lenses for too long or not caring for them properly increases the risk of a corneal infection.
Keratoconus
Keratoconus is an abnormal thinning of the cornea, which develops progressively in both eyes. The thinning starts in the center of the cornea and bulges forward in a conical fashion. This thinning creates an irregular astigmatism that cannot be corrected with eyeglasses, but can be corrected with rigid contact lenses or keratoplasty (corneal transplant) depending on the levels of irregular astigmatism.
Pterygium
Pterygium is a fibrous, fleshy growth on the that extends from the conjunctiva to the surface of the cornea. They typically begin forming on the inner portion of the eye and are slowly progressive. They can become significant enough to affect vision if they grow to the center of the cornea.
Dryness and ultraviolet light exposure are contributing factors to their development, which is why they are most common in patients who are exposed to lots of sun, wind, dust, or harsh climates. We recommend patients wear sunglasses when outdoors, use artificial tear lubricating drops (but not drops that “get the red out”), and limit exposure to irritants in the environment.
Trichiasis
Trichiasis is when the eyelashes point toward the eye and scratch the cornea. This uncomfortable condition can lead to chronic inflammation or infections. Trichiasis treatment involves either redirecting eyelash growth or removing the eyelash, follicle, or both.
If the trichiasis is limited to a single eyelash or just a few eyelashes, your ophthalmologist may remove the problem-causing lash with forceps. However, this may only be a temporary solution if the eyelash grows back again in the wrong direction. If this happens, or if you have multiple lashes growing toward your eye, your ophthalmologist may recommend surgery to have them removed permanently.
Diagnosis and Treatment of Cornea Conditions
In order to ensure your corneal condition is properly diagnosed, it is important that a complete eye examination is performed. The exam will allow the ophthalmologist to fully understand and diagnose your condition. Depending on the results of your exam, you’ll be given recommendations for treatments.
If the cornea has become swollen, misshapen, or scarred, it’s most likely affecting your vision. In many cases, the only way to restore the function of the cornea is to remove damaged or unhealthy cornea tissue and replace it with clear cornea tissue from a donor. This procedure is called a cornea transplant.
Our skilled surgeons specialize in the medical and surgical treatment of cornea and external eye disease. From routine medical treatments to corneal transplants, our specialists are well-versed in a number of interventions.
Baptist Eye Surgeons is an ophthalmological practice dedicated to providing quality eye care to patients whose needs range from routine comprehensive eye examinations to complex eye surgeries. To request an appointment or get directions to our Knoxville and Morristown locations, visit our website. Call us at 865-579-3920 for more information, or visit us online to schedule an appointment.
