A corneal ulcer is an an inflammatory and potentially infective condition of the cornea involving a disruption of its topmost epithelial layer down through its middle or stromal layer. The cornea is the clear, protective covering at the front of the eye and is the first part of the eye to focus light. A corneal ulcer can often be the result of an untreated corneal abrasion (a scratch on the cornea). Once an injury or scratch occurs, bacteria immediately begin invading the wound, which leads to infection and corneal ulcers.
Corneal ulcers occur in people of all ages. Typically the ulcer is infectious, but some corneal ulcers are not. Pain, redness, and vision problems are usually associated with ulcers that contain bacteria. Still, all corneal ulcers should be looked at by an eye care professional to ensure that there is no infection and to help craft an appropriate treatment plan.
Corneal Ulcer Symptoms
Symptoms of corneal ulcers vary from person to person, depending on such factors as the location and size of the ulcer. If the ulcer is caused by bacteria, it may be visible to the naked eye in the form of a white patch on the cornea. Not all corneal ulcers are visible without a microscope, however, especially if they are caused by the herpes simplex virus (discussed further in the causes section of this article). Typically, corneal ulcers cause symptoms such as:
- Pain ranging from mild to severe, but typically severe
- Redness of the sclera and conjunctiva (the white part of eye and its clear cover)
- Photophobia (sensitivity to light)
- Impaired and/or blurred vision
- Watering of the eye
- Clouding of the eye
- Discharge from the eye
- Feeling of foreign body in eye
What Causes Corneal Ulcers?
In most cases, corneal ulcers are caused by germs that enter through a previous injury or scratch to the cornea. The germs may be viral, bacterial, or fungal, or there may be a parasitic infection. If the ulcer is caused by the herpes simplex virus it is called a dendritic ulcer, and it may not be visible to the naked eye. The herpes simplex virus is a common viral infection that many people contract during childhood. Symptoms of this virus typically include cold sores, sore throat, and swollen glands. Rarely does this virus spread to other parts of the body, but this can occur if you touch an infected area and then touch your eye.
Corneal ulcers are more common in contact lens wearers, possibly due to the rubbing of a dirty or defective lens against the surface of the eye. If enough rubbing occurs, the corneal surface can become weak and break, which enables bacteria to enter the eye and begin reproducing and spreading. Contact lens wearers who do not practice proper hygiene also increase their risk of developing corneal ulcers. For example, leaving soft contact lenses in while sleeping, or practicing poor hygiene while removing or adjusting the lenses increases the exposure to bacteria that can lead to infection. Studies have shown that overnight wear of contact lenses is the biggest risk factor for serious corneal infection.
Acanthamoebae (acanthamoeba keratitis) are common eye parasites. Contact lens wearers who fail to remove their lenses before swimming can contract this parasitic infection. Fungal keratitis can also occur after an injury to the cornea involving plant material, or if your immune system is suppressed.
Additional causes of corneal ulcers may include:
- Eye allergies
- Corneal abrasions
- Eyelids that do not close all the way, such as with Bell’s palsy
- Dry eyes
- Immune system disorder
- Inflammatory diseases such as multiple sclerosis and psoriasis
Diagnosing Corneal Ulcers
If you experience symptoms of corneal ulcers, you should contact an eye care professional immediately for a complete eye exam. Untreated corneal ulcers can lead to permanent eye damage and vision loss. During the eye exam your eye doctor will look for signs of infection. In cases in which an ulcer is not visible, eye drops that temporarily stain the eye may be used to identify the ulcer. Typically your eye doctor will use a slit lamp (eye microscope) to look into your eye. Regardless of the visibility of the ulcer, a yellow dye may be used to see the affected area more easily. Visual acuity tests and corneal scrapings may be used to determine the cause of the ulcer. Blood tests may be needed to rule out specific disorders and diseases.
Corneal Ulcer Treatment
In order to treat corneal ulcers, doctors must first determine the cause of the ulcer. Treatment should not be delayed when corneal ulcers develop. If the cause is unknown, antibiotics are prescribed to fight any bacterial infection that may be present. The antibiotics are usually administered in the form of eye drops, sometimes as often as one drop per hour. In some cases, corticosteroid eye drops are prescribed to reduce swelling and inflammation.
If the corneal ulcer is severe, a cornea transplant (keratoplasty) may be needed. During this procedure the diseased or damaged cornea is removed. A new cornea is then grafted onto the eye with tiny sutures (stitches). The sutures are removed after healing is complete, usually several weeks after surgery. Most people see an improvement in their vision within days after the surgery. In some cases, hospital stays as long as two days are required.
Your eye doctor may also recommend you:
- Wear protective glasses
- Take pain medications
- Avoid eye makeup
- Avoid sharing makeup, towels, or eye-drops with others
- Avoid wearing contact lenses during treatment
- Discontinue wearing contact lenses while sleeping
- Wear an eye patch to avoid symptoms such as sensitivity to light
- If a corneal transplant is performed, do not allow water to enter your eye
In some cases, minor but permanent vision changes occur, but most people completely heal from corneal ulcers. Follow-up visits with your eye doctor are typically recommended, regardless of the severity of the ulcer.
Corneal Ulcer Risk Factors
If you had a corneal ulcer in the past, you are considered to be prone to long-term damage to the cornea and may experience noticeable changes in your vision in the future. Other factors that increase your risk of developing ulcers include:
- Wearing contact lenses, especially soft lenses, while you sleep
- Severe dry eye
- Recent infection or injury to eye
- Severe allergies
- Eyelids that do not close completely
- Failure to wear eye protection during athletic activities
- Weakened immune system, such can be caused by HIV
- Work or hobbies that use pointed tools or produce dust, such as farming or construction work
Complications of Corneal Ulcers
Most complications from corneal ulcers occur because the ulcer has been left untreated. Typically, treatment can prevent complications such as:
- Loss of vision
- Scarring on the cornea
- Loss of affected eye due to cataracts or glaucoma
- Spread of infection to other parts of eye and body
When to See Your Eye Doctor
Corneal ulcers should not be ignored. If you are experiencing symptoms of a corneal ulcer, you should seek medical attention immediately. Signs of a corneal ulcer include:
- Severe pain
- Any change in vision
- Feeling of foreign body in eye
- History of scratches to the eye
- History of exposure to chemicals or flying particles
- Excessive discharge draining from eye
Preventing a Corneal Ulcer
If you have an eye infection or injure your eye, you should seek medical attention immediately from an ophthalmologist or optometrist. Early treatment can prevent the ulcer from developing. Symptoms of corneal ulcers should not be ignored. Contact lens wearers should wash their hands before handling contact lenses in order to prevent the transmission of bacteria and foreign objects. Discontinue wearing contact lenses while you sleep. Talk with your eye-care professional about prevention measures you should take during your normal daily activities.
Never let a corneal abrasion turn into a corneal ulcer.
- J. DiGirolamo, MD “The Big Book of Family Eye Care” (Basic Health Publications, 2011) 173-174
- WebMD, Corneal Ulcer, http://www.webmd.com/eye-health/corneal-ulcer