Shingles, or herpes zoster, is a viral infection known for its characteristic painful, burning, or itchy rash. This rash appears along a particular affected nerve, for example in a band on one side of the chest or abdomen that extends around to the back. In fact, the name shingles comes from cingulum, the Latin word for girdle, belt, or sash.
Shingles is caused by reactivation of the varicella zoster virus, the virus that causes chickenpox. After the initial chickenpox infection resolves the virus lives on in nerves all over the body, but is kept in check by the immune system. The risk of shingles therefore increases with any process that can weaken the immune system, including age, illness, and immune-suppressing medications. About one million cases of shingles occur in the US each year.
Up to 20% of shingles episodes involve nerves of the head, where the infection can affect various parts of the eye, including the eyelid, the eye surface, and the deeper portions of the eye. Viral infection of the eye can cause pain, drainage, redness, and sensitivity to light. In some cases it can lead to vision impairment, including blindness.
Shingles in the front of the eye
Shingles can affect the cornea, the curved, transparent dome of tissue at the front of the eye. This is called keratitis, and it can occur as a complication of herpes zoster ophthalmicus (HZO), which refers to shingles with a rash that typically involves one side of the upper face, forehead, and scalp. More than half of patients with HZO may have keratitis.
If you have shingles involving the upper face, forehead, or scalp area, it is important to see an ophthalmologist for a formal eye examination, whether or not you notice any eye symptoms. Keratitis usually develops within one month