What is it?
Herpetic keratitis is an inflammation of the cornea caused by the herpes viral infection group, Herpes Simplex type I being the most common. It can affect other ocular tissues such as the conjunctiva, the retina, and skin of the eyelids.
The human body is the only place where Herpes virus can reproduce and stay alive. Therefore, the disease is spread by physical contact or by saliva. Typically it setles in a latent way through the nervous system, without giving any symptoms.
Several factors and stimulating agents can cause activation of the virus. Menstruation, fever, exposure to ultraviolet light, mild corneal trauma, instillations of some eyedrops, are examples. Atopic or immunocompromised patients are prone to the virus activation.
There are several types of herpetic keratitis. Among these, the epithelial type has an incubation period ranging between 1 and 28 days. The first infection usually goes unnoticed and without symptoms. If the clinical frame is made, a conjunctivitis appears, resembling one that could be caused by any virus. In half of these cases, the virus affects the corneal epithelium, causing small branched wounds in a dendritic or linear form. The patient presents eye pain, tearing, red eye and photophobia. Vision loss occurs when the central area is affected. If left untreated, the disease will progress to larger and deeper corneal ulcers, which are shaped in the form of a geographical map. In most cases only one eye is affected.
Immune herpetic stromal keratitis is another form of involvement. It is an inflammatory reaction to the virus particles in a deeper layer of the cornea. It may appear as a first relapse, or in patients who have already had several recurrences. The patient presents blurred vision, red eye, photophobia and tearing.
Necrotizing stromal keratitis is the most severe form of the viral infection. The virus destroys the corneal tissue and causes an inflammatory reaction. This form of involvement usually occurs in patients who have had repeated recurrences at the corneal epithelium level. In these cases, the virus can damage the cornea very severely, possibly even causing perforation.
The diagnosis of herpetic keratitis is based on clinical examination. In doubtful cases, it can be complemented with the identification of the virus by a test known as PCR.
We must identify each case, as a topical treatment may be necessary using ointments or gel with or without antiviral anti-inflammatory eye drops, or systemic antiviral treatment taken orally.
When the disease process ends with corneal scars and with a significant loss of vision, corneal transplantation is the best option. Still, the virus is latent in neural ganglia, and may be activated in the new transplanted cornea. For this reason, during the first year, an antiviral is administered orally as a prophylactic during the postoperative period.
It is very important for those patients who have been diagnosed with ocular herpes simplex to note that the virus is still in the neural ganglion.They always run the risk of the virus being active, so if any minimal symptom is noticed, they must immediately visit their ophthalmologist in order to be diagnosed and treated as soon as possible.