Definition

Corneal abrasion is an injury to the eye that involves a shallow scratch on the surface of the cornea, which is the front and transparent part of the eye. This injury occurs when the outer layer of the cornea, called the corneal epithelium, is disrupted. Some potential causes include the use of contact lenses, the presence of foreign objects in the eye, or it can even occur spontaneously.

Causes

The cornea can get scratched due to contact with dust, dirt, sand, wood splinters, metal particles, fingernails, makeup brushes, sports equipment, or even the edge of paper. Damaged contact lenses or prolonged use of contact lenses can also increase the risk of corneal abrasion. Corneal abrasions caused by organic materials such as plants or tree branches usually require special attention as they can lead to delayed inflammation inside the eye (iritis).

Other causes of corneal abrasion include rubbing the eyes and dry eyes.

Risk Factor

Corneal abrasion is a common eye injury that can occur in individuals of all age groups. However, there are several factors that can increase the risk of corneal abrasion, including:

• History of injury
• Use of contact lenses
• Male gender, especially if the occupation involves a high risk of eye injury
• Age between 20-34 years
• Working in construction or manufacturing
• Not using eye protection while working

Symptoms

The symptoms and signs of corneal abrasion include:

• Pain or discomfort in the eye
• Difficulty opening the eye
• Sensation of something foreign in the eye
• Gritty feeling in the eye
• Watery eyes
• Redness in the eye
• Sensitivity to light
• Blurred or hazy vision
• Headache

The cornea has many nerve cells. The cells known as pain receptors transmit pain to inform the brain that there is a potential injury to the surface of the eye. In fact, there are hundreds of times more pain receptors on the cornea compared to the skin.

Diagnosis

To diagnose a corneal abrasion, the doctor will inquire about the events leading up to the abrasion and perform an eye examination using a penlight and a slit lamp. Fluorescein staining is the most helpful diagnostic tool for assessing corneal abrasions. To aid in the eye examination, the doctor may administer anaesthesia eye drops (to alleviate pain during the examination).

This examination involves applying a colored liquid called fluorescein to the surface of the eye. The doctor will then examine the cornea using a device called a slit lamp. The colored liquid will adhere to the location of the abrasion, indicating the presence of scratches or discontinuity on the cornea. The shape of the scratch or abrasion can provide clues about the possible cause.

The doctor will also inspect the undersides and insides of the eyelids by flipping them over. Sometimes, very small wood or metal particles can get stuck under the eyelid and cause damage to the cornea.

Management

If you experience corneal abrasion symptoms, follow these steps for first aid:

• Rinse the eye with clean water or flowing saline solution. Washing the eye can help remove foreign objects on the eye's surface.
• Blink your eyes several times. This can eliminate small particles.
• Pull the upper eyelid towards the lower eyelid. This can make the eye watery, helping to flush out foreign particles. This movement can also assist eyelashes in sweeping out foreign objects.

To avoid further injury, pay attention to the following:

• Do not attempt to remove an object embedded in the eyeball or make it difficult to close the eye.
• Do not rub or scratch the eye after an eye injury. This can slow down the healing process and may worsen the injury.
• Do not touch the eyeball with cotton, tweezers, or other tools.
• If you use contact lenses, do not wear them while the eye is healing. Ask your doctor when you can use contact lenses.

The doctor will try to remove the detected foreign object. If the foreign object is under the eyelid, the doctor will remove it usually by flipping the eyelid. If irrigation or swabbing cannot remove the foreign object, a special tool will be used. This attempt of foreign object removal will be done with anaesthesia eye drops.

After successfully removing the object, the doctor will proceed to treat your eye based on the results of the eye examination. Treatment options for corneal abrasion include:

• The doctor may prescribe antibiotic eye drops or ointment to prevent eye infections. Antibiotic ointment provides lubrication for the injured eye. Additionally, the doctor may prescribe eye drops to dilate the pupil, reducing pain. Both of these therapies are the primary treatment for corneal abrasions, especially for larger abrasions. The duration of treatment varies, usually completed after the eye remains symptom-free for 24 hours.
• Applying an eye patch to the affected eye. This is done to prevent blinking that could worsen the corneal abrasion. However, this is not recommended for routine use. Ask the doctor if you need to cover your eye.
• Using moisturizing eye drops or ointment. These medications help moisture the cornea and prevent further injury.
• You may be given special contact lenses to reduce pain and expedite healing.
• Administration of tetanus vaccine or antitetanic serum is only recommended for penetrating eye injuries, not for a simple corneal scratch.
• The use of corticosteroid eye drops or ointment is not recommended as it can slow down healing and increase the risk of infection.

Small abrasions (less than 4 mm) usually do not require pain relief. Mild to moderate pain can usually be managed with non-steroidal anti-inflammatory drugs (NSAIDs). Small corneal abrasions typically heal within one to two days. Larger corneal abrasions may take up to one week to heal.

Complication

Small corneal abrasions typically heal without complications, but larger abrasions can lead to complications such as:

• Corneal ulcer
• Keratitis
• Recurrent corneal erosion syndrome
• Traumatic iritis

Prevention

Preventive measures that can be taken to avoid corneal abrasion include:

• Use goggles or eye protection when engaging in activities that may pose a risk of eye injury, such as cutting grass, woodworking, extreme sports or welding metal.
• Trim nails carefully, especially for infants and children. They may accidentally scratch the cornea with their fingernails.
• Be cautious when you apply makeup to the eyes. Ensure that there are no ingredients that may cause irritation or injury to the eyes. Use safe makeup products and avoid contact with the eyes using sharp applicators.
• If you wear contact lenses, follow the instructions for proper use and care of contact lenses. 

When to See a Doctor?

If you experience symptoms of corneal abrasion, seek medical attention promptly. Without proper management, it can lead to infection and ultimately result in the formation of corneal ulcers.

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