A corneal dendrite is an eye condition affecting the cornea, the clear outer layer at the front of your eye. It is characterized by a distinctive branching, tree-like pattern on the corneal surface, from which the term “dendrite” is derived. When an eye care professional observes this pattern, it strongly indicates a particular underlying cause.
What is a Corneal Dendrite?
A corneal dendrite is a lesion on the cornea, almost exclusively caused by the herpes simplex virus (HSV). HSV-1, the same virus responsible for cold sores around the mouth, is the most common culprit for eye infections. This virus typically enters the body through skin or mucous membrane breaks and can then lie dormant in nerve cells, such as the trigeminal nerve, for extended periods.
Reactivation of the dormant virus can cause it to travel along the nerve pathways, leading to an infection in the eye. While HSV is the overwhelmingly common cause, other less frequent viral infections, such as herpes zoster virus (shingles), can also cause similar branching lesions. The lesions initially appear as small, raised vesicles that coalesce within approximately 24 hours to form the classic dendritic shape as the virus spreads from cell to cell.
Identifying the Symptoms
Symptoms of a corneal dendrite reflect irritation and inflammation. Eye pain is a frequent complaint, often accompanied by redness of the affected eye. Many people describe a gritty sensation or the feeling of having a foreign body in their eye.
Blurred vision is another common symptom, varying in severity with corneal involvement. Sensitivity to light, known as photophobia, is also typical, making bright environments uncomfortable. These symptoms can range from mild discomfort to more intense pain and warrant prompt medical attention.
How Corneal Dendrites Are Diagnosed
Diagnosis of a corneal dendrite begins with a comprehensive eye examination by an eye care professional. A specialized instrument called a slit lamp microscope magnifies the eye’s structures, allowing for a detailed view of the cornea.
A distinguishing technique involves applying fluorescein dye to the eye. This orange dye adheres to damaged or missing corneal cells, making the characteristic branching pattern brightly visible under a cobalt blue light. A thorough medical history, including past cold sores or other viral infections, also aids diagnosis.
Treatment Options
The primary goal of treating a corneal dendrite is to halt viral replication and promote corneal surface healing. Antiviral medications are the primary treatment, administered as eye drops or oral medications. Topical antiviral eye drops, such as ganciclovir or trifluridine, are often prescribed and applied multiple times daily for 7 to 10 days.
Oral antiviral medications, including acyclovir or valacyclovir, may also be prescribed for severe cases or frequent recurrences. Prompt antiviral treatment is important to prevent the infection from worsening and minimize complications. Corticosteroid eye drops are generally avoided during the acute phase of a dendritic ulcer, as they can worsen the viral infection by suppressing the immune response. They might be considered later, under strict medical supervision, to manage inflammation once the active viral infection has resolved.
Long-Term Outlook and Potential Issues
The long-term outlook for a corneal dendrite depends on prompt and effective treatment. If left untreated or if recurrences are frequent, serious complications can arise. One significant potential issue is corneal scarring, which occurs when deeper layers of the cornea are affected. This scarring can cause the normally clear cornea to become cloudy, leading to significant vision impairment or even permanent vision loss.
The herpes simplex virus can remain dormant in the nerves and reactivate periodically, leading to recurrent episodes. Each recurrence contributes to further corneal damage and scarring, potentially necessitating long-term management. Persistent inflammation, even after the active infection subsides, can also contribute to ongoing discomfort and vision problems.