Cornea

There are many diseases that can affect the cornea, causing pain or loss of vision. Disease, infection or injury can cause the cornea to swell (called "edema") or degrade (become cloudy and reduce vision). Common diseases and disorders that affect the cornea include:

• Allergies
• Bullous Keratopathy
• Conjunctivitis ("Pink Eye")
• Dry Eye
• Corneal Dystrophies including Fuchs' Dystrophy and Lattice Dystrophy
• Glaucoma (High Eye Pressure)
• Infections (Viral, Bacterial, Fungal, Other)
• Keratitis (Non-infectious disorders))
• Keratoconus
• Ocular Herpes
• Pterygium
• Stevens-Johnson Syndrome

Treatment for corneal disease can take many forms, depending on the underlying problem as well as the patient's preferences. Some conditions resolve on their own and many can be treated with medication. If the cornea is severely damaged or if there is a risk of blindness, a corneal transplant may be recommended to preserve vision.

Learn more about the cornea and corneal disease from the National Eye Institute

Keratoconus is a progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape. The cornea is the clear, central part of the surface of the eye. In patients with keratoconus, the cone-shaped cornea deflects light and causes distorted vision.

Keratoconus often begins to develop between the teen years and the early 20s, although it can develop at any age. Changes in the shape of the cornea occur gradually, usually over several years. Patients with keratoconus often experience blurred and distorted vision, nearsightedness, and a glaring sensitivity to light.

Early stages of keratoconus can be treated with eyeglasses or soft contact lenses. For progressive keratoconus, treatment methods include rigid gas-permeable contact lenses, INTACS (plastic implants that flatten the cornea), and collagen cross-linking (light-activated vitamin eye drops). If keratoconus persists, corneal transplant surgery can be performed to correct the condition. 

Pterygium is a benign growth of the conjunctiva (lining of the white part of the eye) that grows into the cornea, which covers the iris (colored part of the eye). It can eventually lead to impaired vision.

Patients with pterygium often first notice the condition because of the appearance of a lesion on their eye or because of dry, itchy irritation. Other symptoms include dryness, redness, irritation, inflammation, and tearing. In more severe cases, the pterygium grows over the pupil and limits vision.

The most common pterygium treatment is eye drops (artificial tears) and use of sunglasses. In more severe cases when vision is impaired, surgery may be recommended. 

A corneal abrasion is a scratch or scrape on the cornea, the clear surface covering the front of the eye. This condition occurs when something hits the eye, such as small particles blown by the wind or foreign bodies such as a piece of sand or wood. Abrasions may also be caused by wearing a contact lens for too long or from a fingernail scratch.

Patients with a corneal abrasion may experience:

• Tearing
• Blurred vision
• Eye pain
• Redness
• Muscle spasms causing squinting
• Feeling that there is something in the eye

Corneal abrasions can often be treated at home while washing the eye with clean water and removing a visible particle by blinking or with a soft tissue or cotton swab. If the particle cannot be removed, patients should seek medical attention for this condition. Your doctor may prescribe antibiotic eyedrops or ointment.

Patients can help prevent corneal abrasions and other eye injuries by wearing protective eyegear during sports or physical activity and wearing sunglasses in the sun.

A corneal ulcer is an open sore on the surface of the cornea, the clear tissue that covers the front of the eye. This condition is usually caused by an infection, which may be bacterial, viral or fungal. Some corneal ulcers are also caused by tiny tears in the cornea that may be a result of a scratch or tiny particle.

Patients with a corneal ulcer may experience:

• Redness
• Severe eye pain
• Tearing
• Pus or discharge from the eye
• Blurred vision
• Swollen eyelids
• Sensitivity to light

If you suspect you have a corneal ulcer, you should remove contact lenses and apply a cool compress to your eye and then seek medical attention for this condition. Your doctor will likely prescribe antibiotic eyedrops since this condition is caused by infection. Oral medication may also be prescribed to manage pain. If medication is unsuccessful, an emergency corneal transplant procedure may be performed to prevent perforation of the cornea.

Corneal ulcers can be prevented by wearing eye protection, using artificial tears and washing your hands before handling contact lenses or touching your eyes.