Infections

Corneal Ulcer

A corneal ulcer is an open sore on the cornea, the clear structure overlying the iris, which is the colored part of your eye.

Causes

  • Most corneal ulcers are caused by infections.
    • Bacterial infections cause corneal ulcers and are common in people who wear contact lenses.
    • Viral infections are also possible causes of corneal ulcers. Such viruses include the herpes simplex virus (the virus that causes cold sores) or the varicella virus (the virus that causes chickenpox and shingles).
    • Fungal infections can cause corneal ulcers and may develop with improper care of contact lenses or the overuse of eyedrops that contain steroids.
  • Tiny tears to the corneal surface may become infected and lead to corneal ulcers. These tears can come from direct trauma by scratches or metallic or glass particles striking the cornea. Such injuries damage the corneal surface and make it easier for bacteria to invade and cause a corneal ulcer.
  • Disorders that cause dry eyes can leave your eye without the germ-fighting protection of tears and cause ulcers.
  • Disorders that affect the eyelid and prevent your eye from closing completely, such as Bell’s palsy, can dry your cornea and make it more vulnerable to ulcers.
  • Any condition which causes loss of sensation of the corneal surface may increase the risk of corneal ulceration.
  • Chemical burns or other caustic (damaging) solution splashes can injure the cornea and lead to corneal ulceration.
  • People who wear contact lenses are at an increased risk of corneal ulcers. The risk of corneal ulcerations increases tenfold when using extended-wear soft contact lenses. Extended-wear contact lenses refer to those contact lenses that are worn for several days without removing them at night. Contact lenses may damage your cornea in many ways:
    • Scratches on the edge of your contact lens can scrape the cornea’s surface and make it more vulnerable to bacterial infections.
    • Similarly, tiny particles of dirt trapped underneath the contact lens can scratch the cornea.
    • Bacteria may be on the improperly cleaned lens and get trapped on the undersurface of the lens. If your lenses are left in your eyes for long periods of time, these bacteria can multiply and cause damage to the cornea.
    • Wearing lenses for extended periods of time can also block oxygen to the cornea, making it more susceptible to infections.

Symptoms:

  • Red eye.
  • Pain in the eye.
  • Feeling that something is in your eye.
  • Tearing.
  • Pus or thick discharge draining from your eye.
  • Blurry vision.
  • Pain when looking at bright lights.
  • Swollen eyelids.
  • A white or gray round spot on the cornea that is visible with the naked eye if the ulcer is large.

When to Seek Medical Care

See your doctor if you experience the following signs or symptoms:

  • A change in vision
  • Severe pain
  • Feeling that there is something in your eye
  • Obvious discharge draining from your eye
  • If you have a history of scratches to the eye or exposure to chemicals or flying particles.

Exams and Tests

Because corneal ulcers are a serious problem, you should see your ophthalmologist (a medical doctor who specializes in eye care and surgery).

  • Your ophthalmologist will be able to detect if you have an ulcer by using a special eye microscope, known as a slit lamp. To make the ulcer easier to see, he or she will put a drop containing the dye fluorescein into your eye.
  • If your ophthalmologist thinks that an infection is responsible for the ulcer, he or she may then get samples of the ulcer to send to the laboratory for identification.

Corneal Ulcer Treatment

Self-Care at Home

  • If you wear contact lenses, remove them immediately.
  • Apply cool compresses to the affected eye.
  • Do not touch or rub your eye with your fingers.
  • Limit spread of infection by washing your hands often and drying them with a clean towel.
  • Take over-the-counter pain medications, such as acetaminophen (Tylenol) or ibuprofen (Motrin).

Medical Treatment

  • Your ophthalmologist will remove your contact lenses if you are wearing them.
  • Your ophthalmologist will generally not place a patch over your eye if he or she suspects that you have a bacterial infection. Patching creates a warm dark environment that allows bacterial growth.
  • Hospitalization may be required if the ulcer is severe.

Medications

  • Because infection is a common occurrence in corneal ulcers, your ophthalmologist will prescribe antibiotic eyedrops. If the infection appears very large, you may need to use these drops as often as one drop an hour.
  • Oral pain medications will be prescribed to control the pain. Pain can also be controlled with special eyedrops that keep your pupil dilated.

Surgery

  • If the ulcer cannot be controlled with medications or if it threatens to perforate the cornea, you may require an emergency surgical procedure known as corneal transplant.

Prevention

Seek medical attention from your ophthalmologist immediately for any eye symptoms. Even seemingly minor injuries to your cornea can lead to an ulcer and have devastating consequences, including blindness or loss of the eye.

  • Wear eye protection when exposed to small particles that can enter your eye.
  • If you have dry eyes or if your eyelids do not close completely, use artificial teardrops to keep your eyes lubricated.
  • If you wear contact lenses, be extremely careful about the way you clean and wear your lenses.
    • Always wash your hands before handling the lenses. Never use saliva to lubricate your lenses because your mouth contains bacteria that can harm your cornea.
    • Remove your lenses from your eyes every evening and carefully clean them. Never use tap water to clean the lenses.
    • Never sleep with your contact lenses in your eyes.
    • Store the lenses in disinfecting solutions overnight.
    • Remove your lenses whenever your eyes are irritated and leave them out until your eyes feel better.
    • Regularly clean your contact lens case.

Amniotic membrane has been used for both infectious and sterile ulcers with thinning and perforation. For ulcers with significant tissue loss, amniotic membrane may be applied in layers to build thickness to the defect. Such an intervention is intended to retard protease activity and to provide bulk for the defect in the hopes of promoting faster healing and avoiding cornea transplantation. It can provide a temporizing measure before cornea transplantation or possibly suffice as a permanent treatment.

Treatments of corneal disorders include medicines, corneal transplantation and corneal laser surgery.

Amniotic Membrane & Limbal Stem Cell Transplant

The first amniotic membrane transplant in ophthalmology was performed in 1940 with partial success in the treatment for conjunctival epithelial defect. There with little else done with amniotic membranes until the 1990s. Amniotic membranes were used for the ocular surface reconstruction on severely damaged corneas in a rabbit model. Since then amniotic membranes have been used for a number of different conditions.

The normal ocular surface is made up of corneal, limbal and conjunctival epithelial cells. The limbal stem cells are important in that they are necessary to maintain a smooth and clear corneal surface. These cells in combination with the tear film work together to make the ocular surface healthy which allows for strong visual acuity.

Damage to these cells from diseases or trauma may cause trauma to the normal corneal epithelial. The results can cause a number of conditions on the cornea which eventually will lead to poor visual acuity. The exact mechanisms used by the amniotic membrane to treat the ocular surface are still largely unknown. Doctors are still trying to evaluate if the amniotic membranes are related to limbal stem cell proliferation or epithelialization of the corneal surface. The structure and presence of growth helps to grow the epithelial tissue on the cornea.

When it comes to having an amniotic membrane transplant there are two types of techniques used to perform the procedure. The Inlay technique plays the amniotic membrane graft into the corneal ulcer, then is secured by sutures without extending past the defect in the epithelial. Studies have shown that when this type of technique is used the amniotic membrane acts a basement membrane. However, using this technique may limit corneal transparency for several months after surgery and could affect the vision.

The overlay technique involves the entire corneal surface including the limbus being covered with the amniotic membrane graft. The amniotic membrane functions as a contact lens. The graft will protect the epithelium that is regenerating from the friction caused by the eyelid and palpebral conjunctiva but it will still allow oxygen and moisture reach the epithelium. The transparency of the corneal will remain when the graft eventually detaches or dissolves. Both the inlay and overlay techniques may be used together for medical treatments.

In the field of ophthalmology the used of amniotic membrane for transplants are many. The rediscovery of its use can greatly improve the treatment of ocular surface diseases. Studies are continually being performed to determine new uses for the amniotic membrane on the corneal surface. Amniotic membrane transplants may be the answer to cure for a number of ocular diseases.