Uveitis is an inflammation of the middle layer of the eye which extends from the iris at the front, to the ciliary body holding the lens and then to the choroid to the rear. Depending on the location of the inflammation, the uveitis is described as being anterior (at the front), intermediate or posterior (at the back).
Since 90% of cases of Uveitis are anterior they are often called by another name “iritis”, and eye-care specialists use the terms interchangeably.
Although it’s not certain what causes the various types of uveitis, if the herpes simplex virus (HSV) is thought to be responsible, then the inflammation will be given the specific description “herpetic uveitis”.
In line with most cases of uveitis being of the anterior type, accordingly most cases of herpetic uveitis are the same – anterior type.
The disease is quite rare with an incidence of only 1 in 200,000 of population.
How does the herpes virus figure in uveitis?
There are two types of herpes simplex virus – type 1 is the one that lies dormant in millions of people and gives rise to cold sores or lip blisters, and is probably contracted from being kissed as a child by family members.
The herpes virus in this case can either stimulate uveitis by itself or be contracted through firstly touching the lips and then the eyes. The vast majority of cases of herpetic uveitis stem from the type 1 virus.
The type 2 herpes simplex virus is centred in the genital area and it is quite rare for it to migrate to the eyes. Cases of transfer have been noted with babies born from mothers with the type 2 disease.
It’s fortunate that herpetic uveitis comes from the type 1 as it is readily treatable – when from type 2 the treatment is more complicated as the disease is more serious.
Signs and symptoms
General symptoms include quite a few of those found in many other eye diseases, so diagnosis is difficult without tests and examinations as there are none that point directly to the herpes association.
• Light sensitivity
• Migraine-like eye pain
• “Pink eye”
• Vision is blurry
• Repeated infections
Symptoms found upon examination:
• Intra ocular pressure – usually with standard uveitis it is low, but with herpes it may be higher than normal
• Pupils may be dilated even though no dilating drops have been introduced
• If an anaesthetic is introduced to carry out the examination and the pain associated with the general symptoms persists, then the presence of anterior uveitis itself is not probable.
Topical corticosteroid eye drops such as prednisolone are applied, together with acyclovir taken orally (a brand name being Zovirax) and used to treat herpes. In severe cases oral prednisolone might be required.
Care has to be taken with the use of steroids since they are used in many auto-immune deficiency situations and too quick a reduction in dosage is liable to cause recurrence or complications; a programme of tiered withdrawal needs to be drawn up.