What is a Corneal Abrasion?
A corneal abrasion is a scratch to the epithelium. The cornea is made up of 5 layers, and the epithelium is the outermost layer of the cornea that is exposed to the environment. You may think of the epithelium as equivalent to the skin on our body.
What Causes a Corneal Abrasion?
Most corneal abrasions occur after minor trauma to the eye. Causes include a fingernail, walking into a tree branch, or contact lenses (during their placement or removal), although something as small as a grain of sand can also cause an abrasion!
How Does a Corneal Abrasion Feel?
A corneal abrasion can be extremely painful! The cornea is the most densely innervated part of the human body. Just as a comparison, the cornea is about 500 times more densely innervated than the skin. That means that even a relatively small abrasion can cause significant discomfort. Other common symptoms include redness, light sensitivity, feeling a foreign body in the eye, and blurry vision.
How is a Corneal Abrasion Treated?
When you see an eye doctor for a corneal abrasion, he or she will perform a slit lamp examination using fluorescein dye – a special drop used to identify abrasions. The doctor will also carefully examine the eye for any hidden foreign bodies and evaluate for infections. You will typically be prescribed an antibiotic drop, not necessarily because the doctor thinks the eye is infected, but to prevent any new infection while there is an “opening” on the eye. The abrasion is an open door to infection, and it is important to keep the eye clean while the abrasion heals. Sometimes an antibiotic ointment will be prescribed (instead of or in addition to drops), which plays the additional role of providing a “soothing” surface while the abrasion heals. Every time you blink, your eyelids rub against the abrasion, and this can be quite painful. Placing an ointment or gel onto the cornea will soften the impact of the eyelids, and make you overall more comfortable. This is similar to a scratch on the skin – any time your clothes rub against the scratch, it is painful. But an ointment or cream can lessen that pain.
In cases where the corneal abrasion is related to a contact lens, your doctor may prescribe a slightly stronger antibiotic because contact lens wearers are at higher risk of infection with abrasions. You should not wear your contact lens until after the abrasion has completely healed.
It typically takes 1-5 days for a corneal abrasion to heal. When your eye doctor examines your cornea, he or she may place a numbing drop to make the examination more comfortable. These numbing drops should only be used once or twice in the context of an eye examination, and used in excess may actually prevent the cornea from healing or may make the cornea sicker!
What are Possible Complications of a Corneal Abrasion?
The primary concern after a corneal abrasion is to prevent the development of an infection. Although pretty rare, this is still the most common complication after a corneal abrasion. Another possible complication is that the new epithelium (once healed) may not sit tightly on the underlying layer of the cornea, giving rise to recurrent corneal abrasions with minimal trauma. There are strategies and procedures your doctor may use to treat this situation, if it were to occur.