The Herpes Simplex Virus, known as HSV, is occasionally responsible for the development of herpes of the eye, with epithelial keratitis being the most common variation. There are a number of herpes eye variations depending on where in the eye the herpes itself decides to initiate its inflammatory action. This can be in the cornea (epithelium or stroma), iris or retina.
Herpes keratitis is the most common of the eye herpes and also goes by the name herpetic epithelial keratitis – it affects the cornea on the top superficial layer of the surface of the cornea, and since this layer is called the epithelium the adjective epithelial is applied to it.
(If the herpes virus attacks the eye deeper than the epithelial layer and enters into the stroma, then things become more serious and a new name is given to the disease – herpetic stromal keratitis).
Eye herpes, or ocular herpes as it’s sometimes called, normally comes from type 1 herpes – the cold sore type – but on rare occasions it can come from type 2 herpes which affects the genital area and is far more serious.
Whilst herpes cold sores can be treated by oneself without resort to a visit to the doctor, any kind of eye herpes needs to be brought to the attention of therapeutic optometrist or an ophthalmologist for urgent attention.
Great care needs to be taken by the eye-care professional in determining which variation is present as treatments are specific and an inappropriate treatment can lead to aggravation.
A past symptom is the occurrence at some time or other of type 1 herpes – cold sores on the lips.
Eye pain, sensitivity to light, blurred vision and “pink eye” are regular symptoms with excessive tearing being an additional discomfort. All of these symptoms are indications of other eye diseases and infections, particularly conjunctivitis, so an accurate diagnosis for epithelial keratitis is often fraught with difficulty.
Diagnosis requires careful examination with a microscope specific for eyes called a biomicroscope. This is not a diagnosis that a general practitioner can make and it is certainly not something that you would go to the pharmacist for over the counter drops.
Very often a patient has recurring bouts of the disease. It is essential in such cases that the services of an eye-care specialist such as an optometrist are sought early as loss of vision might be a long term outcome.
How prevalent is the disease?
Millions of people have a dormant herpes virus inside them from being unintentionally infected by family members kissing them as a young child on the lips.
Fortunately less than 1% of those people will ever have an episode of general herpes, and then less than 1% of those will suffer from epithelial keratitis.
Over the years the disease has become more frequently diagnosed and it’s thought that the increased acceptance and wearing of contact lenses is postulated to contribute. In thirty years of practice I (Dr Jim Kokkinakis) have consulted with thousands and thousands of patients wearing contact lenses. Of all the cases of epithelial keratitis that I have seen, to date I cannot remember seeing one case that has coincided with contact lens wear. Even though this could be just a sheer coincidence it is unlikely that contact lenses a definte trigger for herpes keratitis.
As mentioned earlier, care is needed in accurately identifying the particular epithelial keratitis as treatment is specific.
An antiviral topical ointment (Zovirax) or alternatively eye drops should be applied – not to eradicate the virus entirely but to slow its growth until nature takes its course and the infection clears up – a sound way to do things!
It’s important then that the full course of treatment is followed – many eye-care specialists complain that patients do not do this, thinking that their condition has cleared up when this is simply not the case.
The ultimate objective of any treatment is to prevent any long term damage that may occur in the cornea. Recurrent cases are particularly dangerous to a favourable long term outcome. In these cases oral Acyclovir or related oral antiviral called Famvir are prescribed ongoing as a prophylactic to recurrence.