Corneal Ulcer

What is corneal ulcer?

A corneal ulcer is an open sore on the cornea, the clear, dome-shaped window at the front of the eye. The cornea covers the colored part of the eye (the iris) and the pupil, and it plays a major role in focusing light so you can see clearly. When the surface of the cornea breaks down and the tissue underneath becomes damaged or infected, doctors describe this open wound as a corneal ulcer. In medical coding systems, the condition is listed under ICD-10 code H16.0.

Understanding what is corneal ulcer, and why it matters, starts with recognizing that the cornea has no blood vessels of its own. It relies on tears and the fluid inside the eye for nourishment and protection. Because of this, an infection or injury on the cornea can progress quickly and, without treatment, may lead to scarring, permanent vision loss, or in severe cases, loss of the eye. For this reason, a corneal ulcer is generally treated as an urgent eye problem rather than a condition that can safely wait.

Corneal ulcers can affect people of any age. However, they are more common in people who wear contact lenses, especially those who sleep in their lenses or do not clean them properly. Other groups at higher risk include people with severe dry eye, those who have had an eye injury, people with eyelid problems that prevent the eye from closing fully, and individuals with weakened immune systems. In many parts of the world, agricultural injuries — such as a scratch from a plant or a splash of soil — are also a common starting point for corneal ulcers.

Symptoms of a corneal ulcer

Corneal ulcer symptoms often come on quickly and tend to affect one eye. Because the cornea is one of the most sensitive tissues in the body, even a small ulcer can cause significant discomfort. Common signs and symptoms include:

• Eye pain, which can range from a gritty, foreign-body sensation to severe, deep aching
• Redness of the eye, often most intense around the edge of the cornea
• Excessive tearing (watery eye)
• Discharge from the eye, which may be watery or thick and pus-like
• Sensitivity to light (photophobia), making bright rooms or sunlight uncomfortable
• Blurred or decreased vision in the affected eye
• A visible white or gray spot on the cornea, which may be seen in a mirror if the ulcer is large enough
• Swelling of the eyelids or difficulty keeping the eye open
• The feeling that something is stuck in the eye, even when nothing can be seen

Symptoms can vary depending on the cause and stage of the ulcer. In the early stages, a person may only notice mild irritation and redness that resembles ordinary eye strain or conjunctivitis (inflammation of the membrane covering the white of the eye). As the ulcer deepens, pain, light sensitivity, and blurred vision usually become more pronounced, and a whitish spot may appear on the cornea.

The type of infection can also influence how symptoms behave. Bacterial ulcers often progress rapidly, sometimes over a day or two, with heavy discharge and intense pain. Fungal ulcers, which frequently follow injuries involving plant material, tend to develop more slowly and may cause less dramatic symptoms at first, which can delay diagnosis. Ulcers related to the herpes simplex virus may come and go, causing repeated episodes of irritation, redness, and blurred vision in the same eye. Ulcers caused by severe dry eye or an eyelid that does not close properly may build up gradually with burning and a persistent gritty feeling.

It is worth noting that some people, particularly those with reduced corneal sensation from previous viral infections, diabetes, or long-term contact lens wear, may feel less pain than expected. A relatively quiet eye does not always mean the problem is minor.

Causes and risk factors

Corneal ulcer causes fall into two broad groups: infections and non-infectious damage to the corneal surface. In practice, the two often overlap, because a break in the surface of the cornea gives germs an entry point.

Infectious causes

• Bacteria: Bacterial infection is one of the most common causes, particularly in contact lens wearers. Bacteria can multiply on lenses, in lens cases, or in contaminated solutions and then invade a cornea whose surface has been weakened.
• Viruses: The herpes simplex virus (the same family of viruses that causes cold sores) can infect the cornea and cause recurrent ulcers. The varicella-zoster virus, which causes chickenpox and shingles, can also affect the eye.
• Fungi: Fungal ulcers often follow an eye injury involving plants, wood, or soil, and can also occur in people who use steroid eye drops for long periods or who wear contact lenses.
• Parasites: Acanthamoeba is a microscopic organism found in water and soil. It can cause a severe, painful, and hard-to-treat ulcer, most often in contact lens wearers exposed to tap water, swimming pools, or hot tubs while wearing lenses.

Non-infectious causes

• Injury: Scratches (abrasions), foreign bodies, chemical splashes, and burns can damage the corneal surface and allow an ulcer to form.
• Severe dry eye: When the eye does not produce enough tears, or the tears are of poor quality, the corneal surface can break down over time.
• Eyelid and lash problems: Conditions that prevent complete eyelid closure (such as facial nerve weakness), inward-turning eyelids, or lashes that rub against the eye can repeatedly injure the cornea.
• Immune and inflammatory conditions: Some autoimmune diseases (conditions in which the immune system attacks the body’s own tissues), such as rheumatoid arthritis, can cause corneal thinning and ulceration without infection.
• Vitamin A deficiency: Severe lack of vitamin A can weaken the corneal surface, especially in malnourished children.

Risk factors

• Wearing contact lenses, especially sleeping in them, wearing them longer than recommended, or exposing them to water
• Poor contact lens hygiene, such as reusing solution or not cleaning the lens case
• Recent eye injury or eye surgery
• Previous herpes infection of the eye
• Chronic dry eye or eyelid disorders
• Long-term use of steroid eye drops without supervision
• Diabetes or a weakened immune system
• Occupations or activities with a high risk of eye injury, such as farming and construction

Diagnosis

Corneal ulcer diagnosis is made by an eye doctor through a detailed examination, usually supported by laboratory tests when infection is suspected. Because early treatment matters, doctors typically examine the eye on the same day symptoms are reported.

The main steps often include:

• Medical history: The doctor asks about contact lens use, recent injuries, previous eye problems, general health conditions, and any eye drops or medicines being used.
• Vision testing: Reading an eye chart helps document how much the ulcer is affecting sight in each eye.
• Slit-lamp examination: A slit lamp is a special microscope with a bright light that lets the doctor examine the cornea in fine detail. Most corneal ulcers can be seen directly with this instrument as a whitish or gray area on the cornea.
• Fluorescein staining: A drop of harmless orange-yellow dye called fluorescein is placed on the eye. Under blue light, the dye highlights any break in the corneal surface, making the size and shape of the ulcer easier to see.
• Corneal scraping and cultures: If an infection is suspected, the doctor may gently scrape a small sample from the ulcer after numbing the eye with anesthetic drops. The sample is sent to a laboratory to identify the bacteria, fungus, virus, or parasite responsible and, where relevant, to test which medicines are likely to work against it.
• Additional tests: In some cases, doctors may use imaging of the cornea, measure corneal sensation, examine the eyelids and tear film, or order blood tests if an underlying immune condition is suspected. Contact lenses and lens cases may also be sent for testing.

The results of these tests help the doctor distinguish a corneal ulcer from other conditions that can look similar, such as a simple corneal abrasion, conjunctivitis, or inflammation inside the eye, and guide the choice of treatment.

Treatment options for corneal ulcer

Corneal ulcer treatment depends on the cause, the size and depth of the ulcer, and how much the vision is affected. Because an untreated ulcer can scar the cornea or perforate (create a hole in) the eye, watchful waiting is generally not appropriate for a suspected corneal ulcer; treatment usually begins promptly, sometimes even before laboratory results are available. Care is typically provided by an ophthalmologist, a doctor who specializes in eye diseases and surgery. Within hospital settings such as Acibadem, this condition is managed by the ophthalmology department.

Medications

• Antibiotic eye drops are the mainstay of treatment for bacterial ulcers. For severe ulcers, drops may need to be applied very frequently at first — in some cases every hour, including at night — and the schedule is gradually reduced as the eye improves.
• Antifungal eye drops or tablets are used for fungal ulcers. These infections often respond more slowly and may require weeks of treatment.
• Antiviral medicines, given as eye drops, ointment, or tablets, are used for ulcers caused by herpes viruses.
• Anti-parasitic drops are used for Acanthamoeba infection, usually over a prolonged course.
• Pain relief may include oral pain medicine and drops that relax the muscles inside the eye to reduce aching and light sensitivity.
• Steroid eye drops reduce inflammation and scarring but can worsen certain infections, so they are used cautiously, only under close medical supervision, and usually only after the infection is clearly responding to treatment.

People being treated for a corneal ulcer are generally told to stop wearing contact lenses in both eyes until the doctor confirms it is safe, and to avoid eye makeup and rubbing the eye. Some patients with severe ulcers are admitted to the hospital so that drops can be given on schedule and the eye can be monitored closely.

Procedures and surgery

• Debridement: The doctor may gently remove loose or infected tissue from the ulcer surface to help medicines penetrate and to obtain samples for the laboratory.
• Tissue adhesive (medical glue): If the cornea becomes very thin or develops a small perforation, a special glue may be applied to seal the area temporarily.
• Amniotic membrane grafting: A thin layer of donated placental tissue can be placed on the eye to promote healing in ulcers that are not closing on their own.
• Tarsorrhaphy: In ulcers related to poor eyelid closure, the eyelids may be partially sewn together temporarily to protect the cornea while it heals.
• Corneal transplantation (keratoplasty): If the ulcer perforates the eye or leaves a dense scar in the center of the cornea that significantly reduces vision, surgeons may replace the damaged cornea with healthy donor tissue. Transplantation may be done urgently to save the eye or later, once the infection has resolved, to improve sight.

Follow-up is an essential part of treatment. Doctors usually re-examine the eye frequently, sometimes daily at first, to confirm that the ulcer is shrinking and to adjust medicines if it is not.

Living with corneal ulcer and outlook

The outlook after a corneal ulcer depends largely on its cause, size, depth, location on the cornea, and how quickly treatment began. Small ulcers near the edge of the cornea that are treated early often heal within one to a few weeks, in many cases with little or no lasting effect on vision. Larger, deeper, or centrally located ulcers, and those caused by fungi or Acanthamoeba, tend to take longer to heal and carry a higher risk of scarring.

When an ulcer heals, it may leave a scar on the cornea. A scar at the edge of the cornea may have no noticeable effect, while a scar in the center — directly over the pupil — can blur vision permanently. In such cases, glasses, special contact lenses fitted after full healing, or corneal transplantation may be considered to improve sight. Your doctor can explain which options are realistic in your individual situation.

During recovery, most people are advised to take their drops exactly as prescribed, attend all follow-up visits, protect the eye from dust and injury, and avoid contact lenses and swimming until cleared by the doctor. Light sensitivity often improves gradually; sunglasses can make daily activities more comfortable in the meantime.

Prevention matters for anyone who has had a corneal ulcer, particularly contact lens wearers. Helpful habits include washing hands before handling lenses, never sleeping or swimming in lenses unless specifically approved by an eye doctor, replacing lenses and cases as recommended, using fresh solution every time, and never rinsing lenses with tap water. People with dry eye, eyelid problems, or a history of herpes eye infections may need ongoing care to reduce the risk of another ulcer.

Frequently asked questions

What is a corneal ulcer in simple terms?

A corneal ulcer is an open sore on the clear front window of the eye, most often caused by an infection or an injury to the eye’s surface. Because the cornea is essential for clear vision and can be damaged quickly, doctors treat a corneal ulcer as an urgent problem that needs prompt examination and, in most cases, immediate treatment.

Can a corneal ulcer heal on its own?

Very small surface defects can sometimes close without treatment, but a true corneal ulcer — especially an infected one — generally should not be left to heal on its own. Without appropriate medicine, an ulcer can deepen, scar the cornea, or even perforate the eye. If you suspect a corneal ulcer, it is safest to have the eye examined by an eye doctor as soon as possible rather than waiting to see if it improves.

How serious is a corneal ulcer?

A corneal ulcer is considered a potentially sight-threatening condition. Many ulcers heal well when treated early, but delayed or inadequate treatment can lead to permanent scarring, reduced vision, or, in severe cases, loss of the eye. The seriousness depends on the cause, how deep and large the ulcer is, and where it sits on the cornea, which is why an early, accurate diagnosis matters.

How long does a corneal ulcer take to heal?

Healing time varies widely. A small bacterial ulcer treated early may improve noticeably within days and heal over one to a few weeks. Fungal and parasitic ulcers often take considerably longer, sometimes many weeks or months of treatment. Your doctor will monitor the ulcer at regular follow-up visits and can give you a more realistic timeline based on how your eye responds.

Will a corneal ulcer affect my vision permanently?

Not always. Many people recover good vision, particularly when the ulcer is small, located away from the center of the cornea, and treated promptly. However, ulcers can leave scars, and a scar over the pupil may cause lasting blur. If a significant scar remains after healing, options such as glasses, specially fitted contact lenses, or corneal transplantation may be discussed with your ophthalmologist.

Can I wear contact lenses again after a corneal ulcer?

Often yes, but only after the eye has fully healed and your eye doctor confirms it is safe. Because contact lens wear is one of the main risk factors for corneal ulcers, your doctor may recommend changes such as switching to daily disposable lenses, stricter hygiene routines, or shorter wearing times. Some people with severe or recurrent ulcers may be advised to stop lens wear altogether.

What is the difference between a corneal ulcer and a corneal abrasion?

A corneal abrasion is a scratch on the surface of the cornea, similar to a graze on the skin, and it usually heals quickly with simple care. A corneal ulcer is a deeper, open sore that often involves infection and inflammation of the underlying tissue. An abrasion can turn into an ulcer if germs enter the wound, which is one reason eye scratches — especially in contact lens wearers — should be checked by a doctor.

When to see a doctor

A suspected corneal ulcer is an eye emergency. Seek medical care promptly — ideally the same day — if you notice any of the following warning signs, especially if you wear contact lenses or have recently injured your eye:

• Sudden or worsening eye pain that does not settle within a few hours
• A white or gray spot visible on the cornea
• Blurred or decreasing vision in one eye
• Marked redness with discharge or crusting
• Severe sensitivity to light or difficulty keeping the eye open
• Pain or irritation that continues after removing a contact lens
• Symptoms following an eye injury, chemical splash, or contact with plant material or soil
• Fever, spreading eyelid swelling, or a generally unwell feeling together with a painful red eye

If you wear contact lenses and develop a painful red eye, remove the lenses immediately, keep them and the case for possible testing, and do not put lenses back in until a doctor has examined your eye. Avoid using leftover eye drops from previous problems, particularly steroid drops, as these can make some infections worse. Early examination and treatment give the best chance of protecting your sight.