Eye herpes: Forms, symptoms and causes of ocular herpes
Caused by the type 1 herpes simplex virus, eye herpes (ocular herpes) is a common, recurrent viral infection affecting the eyes. This type of herpes virus can cause inflammation and scarring of the cornea that sometimes is referred to as a cold sore on the eye. Herpes of the eye can be transmitted through close contact with an infected person whose virus is active.
The National Eye Institute (NEI) says an estimated 400,000 Americans have experienced some form of ocular herpes, with close to 50,000 new and recurring cases occurring each year.
Forms of eye herpes
Ranging from a simple infection to a condition that can possibly cause blindness, there are several forms of eye herpes:
Herpes keratitis is the most common form of eye herpes and is a viral corneal infection. Ocular herpes in this form generally affects only the top layer, or the epithelium, of the cornea, and usually heals without scarring.
Stromal keratitis occurs when the infection goes deeper into the layers of the cornea. This can lead to scarring, loss of vision and, occasionally, blindness. Stromal keratitis is thought to be caused by a late immune response to the original infection. According to NEI, about 25% of new and recurring cases of herpes eye infections result in stromal keratitis.
Iridocyclitis is a serious form of eye herpes where the iris and surrounding tissues inside the eye become inflamed, causing severe sensitivity to light, blurred vision, pain and red eyes. Iridocyclitis is a type of uveitis that affects the more frontal portions of the inside of the eye. When this infection occurs in the retina or the inside lining of the back of the eye, it is known as herpes retinitis.
Eye herpes symptoms and signs
Various signs and symptoms are associated with an ocular herpes outbreak. You may experience inflammation of the cornea, which can cause an irritation or sudden and severe ocular pain. Also, the cornea can become cloudy, leading to blurry vision.
Other characteristics of eye herpes include:
Recurrent eye infections
Foreign body sensation
Watery eye discharge
Due to these numerous symptoms, your optician may overlook an initial diagnosis of ocular herpes in its very early stages.
What causes eye herpes?
Eye herpes is transmitted through contact with another person who is having an outbreak, or through self contact and contamination during an active herpes infection (such as a cold sore of the lip).
The herpes simplex virus enters the body through the nose or mouth and travels into the nerves, where it may be inactive. The virus can remain dormant for years and may never wake up.
The exact cause of an outbreak is unknown, but stress-related factors such as fever, sunburn, major dental or surgical procedures and trauma are often associated with incidents.
Once the initial outbreak occurs, the NEI says untreated eye herpes has about a 40% to 50% chance of returning. There is no specific time frame for ocular herpes to reappear; it could be several weeks or even several years following the original occurrence. Although symptoms usually present themselves in only one eye, the virus possibly could affect the other eye as well.
Eye herpes treatment
Treatment for eye herpes depends on where the infection is located in the eye — in the corneal epithelium, corneal stroma, iris, retina, etc. Some ocular herpes treatments could aggravate the outbreak and therefore should be considered on a case-by-case basis.
If the corneal infection is only superficial, it can normally be alleviated by using antiviral eye drops or ointments, or oral antiviral pills.
Zirgan (Sirion Therapeutics) is approved by the United States Food and Drug Administration (FDA) as a topical antiviral treatment for eye herpes. The treatment (ganciclovir ophthalmic gel, 0.15%) involves instilling eye drops five times daily until the related corneal ulcer heals. You should not wear contact lenses while undergoing treatment with Zirgan, which is marketed in Europe as Virgan.
Other treatments for herpes eye infections include Viroptic (trifluridine) eye drops and Vira-A (vidarabine) ointment.
Also, in the Acyclovir Prevention Trial (APT), scientists found that the antiviral drug acyclovir, taken by mouth, reduced by 41% the probability that any form of herpes of the eye would return in patients who had the infection in the previous year. These same researchers also noted a 50% reduction in the rate of return of the more severe form of the disease, stromal keratitis.
Steroid drops can help decrease inflammation and prevent corneal scarring when the infection appears deeper in the corneal layers. Steroid drops are almost always used simultaneously with antiviral drops.
Steroid drops decrease the effectiveness of the eye's immune system. Therefore, people with a history of ocular herpes should use only a steroid drop specifically prescribed by their optician.
Steroid drops have been known to cause a recurrent eye herpes infection in susceptible patients. Also, an antibiotic eye drop along with a therapeutic contact lens may be used to prevent a secondary bacterial infection while the herpes eye infection is being treated.
Surgery may be required if scarring occurs in the cornea and the treatments including the steroids do not help clear the center of the cornea. In cases where corneal scarring is permanent, a corneal transplant may restore vision.
Although eye herpes has no cure, treatment can help control outbreaks.
Incidence, recurrence, and outcomes of herpes simplex virus eye disease in Olmsted County, Minnesota, 1976-2007: the effect of oral antiviral prophylaxis. Archives of Ophthalmology. September 2010.
Acyclovir for the prevention of recurrent herpes simplex virus eye disease. The New England Journal of Medicine. July 1998.
Page published on Tuesday, 23 June, 2020