The term “corneal disease” refers to a variety of conditions that affect mainly the cornea. Some types of corneal disease include:
Keratitis is an inflammation of the cornea. It occurs sometimes when infections from viruses, bacteria or fungi enter the cornea. This may cause inflammation, infection and/or ulceration of the eye. Though uncommon, this type of infection can arise after injury from wearing contact lenses.
Symptoms of keratitis include:
- Blurred vision
- Extreme sensitivity to light
- Treatment most commonly includes antibiotic or anti-inflammatory eye drops.
Ocular Herpes (Herpes of the Eye)
This is a viral infection of the eye. The most common cause of ocular herpes is the virus HSV1, the same virus that causes cold sores. It can also result from the sexually transmitted herpes virus, HSV2, the same viral infection that causes genital herpes.
Ocular herpes causes sores to develop on the surface of the cornea. Over time, the inflammation can spread deeper into the cornea and eye. While there is no cure for ocular herpes, it can often be controlled with the use of antiviral drugs.
Herpes Zoster (Shingles)
Shingles is a recurrence of the chickenpox virus in people who have already had the disease. After having chickenpox, the virus usually remains inactive within the nerves of the body. Herpes zoster occurs when it travels down these nerves, infecting specific parts of the body, like the eye.
Herpes zoster can cause painful blisters or lesions on the cornea and can cause uveitis, inflammation inside the eye. Corneal lesions can usually heal by themselves, but antiviral treatment and/or topical steroid eye drops may be prescribed to reduce the inflammation.
Shingles can occur in anyone exposed to the chickenpox virus, but there is an increased risk in:
- Older adults, especially over age 80
- People with a weakened immune system
One of the most common types of corneal degeneration is Keratoconus. It is a progressive disease where the cornea thins and changes shape. Changing the curvature of the cornea, Keratoconus causes either mild or severe distortion, called astigmatism, and usually nearsightedness. This type of degeneration may also result in swelling and scarring of the cornea as well as vision loss.
Possible causes of keratoconus include:
- Eye diseases
- Other conditions such as Down’s Syndrome, osteogenesis imperfecta, Addison’s disease, Leber’s congenital amaurosis, and Ehlers-Danlos Syndrome
Initially, the condition is correctable with glasses or soft contact lenses. Keratoconus is progressive however, and rigid gas-permeable lenses may become necessary. In approximately 10-15% of patients with keratoconus, a corneal transplant may also be necessary.
Map-dot-fingerprint dystrophy is the abnormal appearance of the basement membrane of the epithelium of the cornea. This dystrophy is named for the forms that appear resembling maps, dots and fingerprints, where the membrane grows irregularly.
This corneal condition occurs most often in adults between the ages of 40 and 70. It can also occur in children as a result of heredity. In most cases, the condition is painless and causes no vision loss. However, in some cases it can cause severe epithelial erosion, exposing nerves lining the cornea and causing:
- Moderate to severe pain
- Increased sensitivity to light
- Excessive tearing
- A feeling of foreign object in the eye
Treatment may include eye patching, bandage, soft contact lenses, eye drops and ointments. Occasionally, corneal scraping may be required to treat the problem.
Fuchs’ dystrophy is the gradual deterioration of endothelial (inner) cells. While the causes of the deterioration are yet unknown, it can begin to appear in people in people ages 30 to 40, but vision often does not become impaired until roughly 20 years later. In addition, it is more commonly found in women than men. As endothelial cells thin over time, the cornea is less capable of removing water from the stroma, causing it to swell and distort vision. Haze and small blisters on the corneal surface may also appear.
An early sign of Fuchs’ dystrophy includes awakening with blurred vision that clears up during the day. As the disease worsens, swelling becomes more consistent and vision blurs.
Treatment for Fuchs’ dystrophy may include:
- Soft contact lenses
- Drying of blisters
- Corneal transplant
- DSAEK, a new form of endothelial transplant
Lattice dystrophy is characterized by abnormal protein fibers found throughout the stroma, making the cornea cloudy and reducing vision. In some people, these proteins can cause epithelial erosion. Although this condition can occur at any age, early changes can be seen in childhood.
Treatment of lattice dystrophy includes:
- Prescription eye drops
- Eye patching
- Corneal transplant