Herpes Keratitis

Herpes simplex virus, which resides in the body, infects the cornea, causing herpes keratitis. The main symptoms are tearing, glare, a foreign body sensation, difficulty in seeing, and redness of the eye.
It’s important to continue appropriate treatment with antiviral drugs. The disease is prone to recurrence, and in some cases, patients may suffer from vision loss.

This article describes following topics.

・Types and symptoms of herpes keratitis
・How to treat the epithelial and stromal types
・How to prevent herpes keratitis

Infection of the cornea with herpes viruses is called herpes keratitis. There are nine types of herpes viruses,but only two are associated with humans: herpes simplex virus (HSV) and varicella zoster virus (VZV).
Many people are infected with the herpes virus during childhood, and once infected, it has the property of remaining dormant in the body even after the symptoms have disappeared. As shown in the figure, the herpes virus lies dormant in the trigeminal nerve, which is divided into three parts, and when it is reactivated by fever or stress, it forms lesions on the cornea.

Besides herpes keratitis, there are other well-known types of herpes, such as oral herpes, which occurs around the mouth, and genital herpes, which occurs on the genitals, which can be transmitted to others through direct contact with the lesions.
Furthermore, herpes often recurs and can lead to vision loss or blindness, so proper treatment is required every time an outbreak occurs.

Depending on where keratitis occurs, herpes keratitis can be classified into epithelial, stromal, and endothelial types. The most common types are epithelial and stromal.
The main symptoms of herpes keratitis are tearing, glare, a feeling of a foreign body sensation, difficulty in seeing, and redness around the eye. In many cases, symptoms appear in only one eye.

Epithelial type

This type of keratitis causes symptoms in the epithelial layer on the surface of the cornea. It is called dendritic keratitis because it presents with dendritic lesions with terminal bulbs.
A definitive diagnosis is made by swabbing the affected area to check for the presence of the virus, but in many cases the diagnosis can also be made based on the characteristic shape of the ulcer when examined with a slit lamp microscope.

Stromal type

The stromal layer is in the center of the cornea that is more internal than the epithelium. Inflammation occurs as a result of the immune system’s defensive response to viruses and is called disciform keratitis because the cornea in the inflamed area becomes swollen and cloudy.
It’s important to note that superficial herpes keratitis recurs, it may to stromal keratitis, resulting in vision loss due to corneal clouding and other problem.

Herpes keratitis is treated with antiviral and antibacterial medicines. For recovery, it’s important to continue correct treatment according to the ophthalmologist’s prescription.

Treatment of the Epithelial Type

For epithelial herpes, treatment is with the antiviral drug acyclovir eye ointment to suppress the growth of the herpes virus, and antibacterial eye drops are often prescribed to prevent bacterial infection.
Apply the eye ointment to the lower eyelids 5 times a day, close your eyes and wait for the medicine to be distributed throughout the eye. This should be continued for about 2 weeks.

Treatment of Stromal Type

In the stromal type, steroid eye drops are used in addition to antiviral agents to reduce viral proliferation and inflammation. Steroid medications may worsen corneal lesions if not used correctly.
It is important to note that if the cornea remains cloudy, it may be difficult to restore vision, and a corneal transplant may be necessary if vision is severely impaired.

Even after the symptoms have disappeared, the herpes virus remains dormant deep within the nerves, and there have been reported cases of recurrence within 2 to 3 years.
There is no way to completely prevent recurrence. However, there are cases of recurrence due to poor physical condition, so leading a regular lifestyle is considered to be the best way to prevent recurrence.

What is the cause of herpes keratitis?

The direct cause is the infection of the cornea with the herpes simplex virus, which causes an immune response. The herpes virus itself is already present in many people and is normally latent in the body. Stress, fever, or other health problems can trigger the onset of herpes keratitis.

Can herpes keratitis be spread to others?

Although herpes can be spread to others through direct contact with lesions, herpes simplex rarely spreads from person to person to cause eye disease.
A rash in one eye rarely spreads to the other eye, even if you are the victim, and unlike viral conjunctivitis, which is highly contagious, you may not need to miss work or school.

Can herpes keratitis be cured?

Herpes keratitis can be properly treated with antiviral drugs, but the herpes virus remains dormant in the body, so there is a possibility of recurrence. To prevent recurrence, try to lead an orderly life and keep yourself in good health.