At the front of the eye is a clear layer of tissue called the cornea. The cornea is the window of your eye and permits light to enter the eye. Tears constitute the natural defense against bacteria, viruses, or fungi for the cornea.
A corneal ulcer is an open sore that forms on the cornea, usually caused by infections. Even small injuries to the eye, or erosion caused by wearing contact lenses too long or while sleeping, can lead to infections.
The main cause of corneal ulcers is infection. Common infections that may lead to corneal ulcers are:
This infection mostly happens to contact lens wearers.
Herpes Simplex Keratitis
Herpes simplex keratitis is a viral infection that causes repeated flare-ups, which involve lesions or sores in the eye. Repeated flare-ups can be triggered by a number of things, including stress, exposure to sunlight, or anything that weakens the immune system.
This is a fungal infection that develops after an injury to the cornea involving a plant or plant material. Fungal keratitis can also develop in people with weakened immune systems.
Other causes of corneal ulcers include:
- dry eye
- eye injury
- inflammatory disorders
- wearing nonsterilized contact lenses
- vitamin A deficiency
People who wear expired soft contact lenses or wear disposable contact lenses for an extended period (including overnight) are at an increased risk for developing corneal ulcers.
You may notice signs of an infection before you are aware of the corneal ulcer. These symptoms include, but are not limited to:
- itchy eye
- watery eye
- pus or eye discharge
- burning or stinging sensation in the eye
- red or pink eye
- sensitivity to light
Symptoms of the corneal ulcer itself include:
- eye inflammation
- sore eye
- excessive tearing
- blurred vision
- white spot on your cornea
- swollen eyelids
- pus or eye discharge
- sensitivity to light
- feeling like something is in your eye
All symptoms of corneal ulcers are severe and should be treated immediately to prevent blindness. A corneal ulcer itself looks like a gray or white area or spot on the usually transparent cornea. Some corneal ulcers will be too small to see without magnification, although you will be able to feel the symptoms.
An eye doctor can diagnose corneal ulcers during an eye exam.
Fluorescein Eye Stain
One test used to check for a corneal ulcer is a fluorescein eye stain. This test is performed by placing a drop of orange dye onto a thin piece of blotting paper. The blotting paper is then lightly touched to the surface of your eye to transfer the dye to your eye. The doctor will then shine a special blue light onto your eye to look for any areas that appear green through a special microscope called a slit-lamp. Corneal damage will show green when the blue light is shined on it.
Scraping the Ulcer
If your doctor spots an ulcer on your cornea, he or she will further investigate to find out what caused it. Your doctor may determine the cause by numbing your eye with eye drops, then gently scraping the ulcer to obtain a sample of it. He will test the sample to find out if it contains bacteria, fungi, or a virus.
Once your eye doctor discovers what caused the corneal ulcer, he or she can prescribe an antibacterial, antifungal, or antiviral eye medication to treat the underlying problem. If the infection is bad, your doctor may put you on antibacterial eye drops while he tests the ulcer scrapings to find out the cause of the infection. In addition, you may have to use corticosteroid eye drops. These drops are normally prescribed in cases where the eye is inflamed and swollen.
During treatment, your doctor will ask you to avoid the following:
- wearing contacts
- wearing makeup
- taking other medications
- touching your eye unnecessarily
In severe cases, the corneal ulcer may warrant a corneal transplant. A corneal transplant involves the surgical removal of the corneal tissue and its replacement with donor tissue. According to the Mayo Clinic, a corneal transplant is a fairly safe procedure. But like any surgical procedure, there are risks. This surgery may cause future health complications such as:
The best way to prevent corneal ulcers is to seek treatment as soon as you develop any symptom of an eye infection, or as soon as you receive an eye injury.
Other helpful preventative measures include:
- avoid sleeping while wearing your contact lenses
- cleaning and sterilizing your contacts before and after wearing them
- rinsing your eyes to remove any foreign objects
- washing your hands before touching your eyes
Although corneal ulcers are treatable, and most people recover quite well after treatment, a reduction in eyesight may occur. Some people may also develop a severe loss of vision along with visual obstruction due to scarring over the retina.
Corneal ulcers can also cause permanent scarring on the eye.
In rare cases, the entire eye may suffer damage.