Herpes zoster, commonly known as shingles, is caused by the same virus responsible for chicken pox. After the initial exposure, herpes zoster lies dormant in certain nerve fibres. It may become active as a result of many factors such as: aging, stress, suppression of the immune system, and certain medications.
Because of the layout of the nerves that herpes zoster resides in, it only affects one side of the body or face during an outbreak. It begins as a rash that lead to blisters and sores on the skin. When the nerve branch that supplies the eye is involved, the forehead, nose, and eyelids may also be affected. Sores on the nose are a key signal of possible eye involvement.
Herpes zoster can cause several problems with the eye and surrounding skin that may have long term effects. Inflammation and scarring of the cornea, along with conjunctivitis (inflammation of the conjunctiva) and iritis (inflammation of the iris) are typical problems that require treatment. In some cases, the retina and optic nerve are involved. Eye problems caused by severe or chronic outbreaks of herpes zoster may include: glaucoma, cataract, double vision, and scarring of the cornea and eyelids.
Many who experience this infection find it extremely painful. This acutely painful phase usually lasts several weeks; however, some continue to experience pain or neuralgia long after the outbreak has cleared. This is known as post-herpetic neuralgia.
Signs and Symptoms
Herpes zoster causes a wide range of problems affecting the skin and the eye. They range in severity depending on the extent of the outbreak. Some problems listed occur indirectly from the inflammation caused by the disease.
Problems affecting the body
- Flu-like symptoms (fever, headache, fatigue)
- Red, sensitive, sore skin
- Blisters and sores on the skin
- Pain (may be burning or throbbing), itching and tingling
Problems affecting the eye
- Light sensitivity
- Swollen eyelids
- Dry eyes
- Blurred vision (depending on how the eye is affected)
- Corneal inflammation that may lead to scarring
- Inflammation inside the eye and optic nerve
- Double vision
- Loss of sensation
Detection and Diagnosis
When the eye is affected, the eye care practitioner will perform a thorough examination with a slit lamp microscope and an ophthalmoscope. Visual acuity and intraocular pressure are also monitored. Signs of breakout on the face and body are noted.
Herpes zoster is treated with anti-viral, pain and anti-inflammatory medications. Eye drops and ointments may be prescribed to treat ocular problems. In some cases, secondary conditions caused by herpes zoster may require surgery.
Those who are infected should avoid contact with people who may be more susceptible to contracting the disease such as: the elderly, children, pregnant women, or anyone with a compromised immune system.
Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.