Shingles are the second presentation of the varicella zoster virus that causes chicken pox. The disease results from reactivation of the virus within sensory nerve roots called dorsal root ganglia. According to Mayo Clinic ophthalmologist Dr. Thomas J. Liesegang, eye shingles occur when the virus strikes the ophthalmic division of cranial nerve V, the trigeminal nerve. Eye shingles produce symptoms of variable severity, ranging from eye irritation to blindness that may be permanent without prompt initiation of antiviral drugs.
Prevalence
According to a 2008 report in the journal "Opthalmology," 20 to 30 percent of people infected with chicken pox will eventually develop shingles. About half of people who do not take antiviral drugs develop some degree of eye involvement. Ten to 20 percent of people develop symptoms of full-blown zoster ophthalmicus.
Anatomy
The ophthalmic division of cranial nerve V divides into three branches: the nasociliary, frontal and lacrimal branches. According to Liesegang, the frontal nerve is most commonly involved, usually signaled by the presence of forehead lesions. The nasociliary nerve supplies the sinuses, the skin of the eye lids, the conjunctiva, the sclera, cornea, iris and choroids plexus, as well as the skin of the bridge, tip and side of the nose. Nasociliary involvement predicts vision loss, including corneal denervation, says Liesegant. The lacrimal branch mainly affects eye lubrication.
Course
The symptoms of eye shingles exhibit an acute, chronic or relapsing course, depending on the mechanism involved. Acute symptoms, as the name implies, occur during the acute episode of shingles and results from active inflammation of the affected nerves. Chronic symptoms persist for months, years or may even be permanent. They result from sensitization and scarring within affected nerves. Relapsing symptoms occur in people with recurrent shingles. Recurrent shingles rarely occur, except in people with immune system problems such as AIDS, certain kinds of cancers and those who take immune suppressing drugs such as organ transplant recipients and people with autoimmune diseases like rheumatoid arthritis.
Clinical Features
Symptoms of eye shingles include 5mm to 10 mm blisters on a base of red, raised skin on the skin of the forehead and scalp, around the eye, the eye lids or the tip, side and bridge of the nose, depending on the nerve branches involved. Tingling, itching, burning or soreness typically precedes the appearance of lesions by one to five days, says the Centers for Disease Control and Prevention. Some people develop an eyelid droop or prominent swelling around the eyes. Other complaints, according to the American Academy of Family Physicians, include eye pain that may be extreme, eye redness, sensitivity to light and eyelid swelling. While shingles usually affect just one side of the body, with eye shingles, both eyes may be involved because of the anatomy of the cranial nerves.
Complications
As acute shingles subside, many patients experience residual lid droop, lid scarring, deep pits on the forehead and scalp and loss of eye pigmentation, says Liesegang. The lids may contract due to scar tissue, turning either inward or outward. Doctors refer to inward lids as entropion and outward lids as ectropion. Entropion lids cause eye irritation due to lash abrasion. Ectropion lids initially cause constant tearing, followed later by dry eyes and the formation of scar tissue. Eye shingles can also cause blindness or less severe vision loss by a variety of mechanisms, warns Liesegang.
Treatment
Eye shingles respond to drugs that control the replication of the varicella zoster virus, including acyclovir, valacylovir and famciclovir. According to a 2008 report in the "American Journal of Emergency Medicine," initiation of antiviral drugs within 72 hours of the appearance of symptoms appears to reduce the risk of complications due to eye shingles from 50 percent to between 20 and 30 percent. The addition of oral or topical steroids further reduces the risk of complications and may decrease or prevent the worsening of acute pain.
References
- "Opthalmology;" Herpes Zoster Ophthalmicus; T.J. Liesegang; 2008
- American Academy of Family Physicians: Herpes Zoster Ophthalmicus
- "American Journal of Emergency Medicine;" Herpes Zoster Ophthalmicus; W.P. Carter et al.; 2008
- Centers for Disease Control and Prevention: Shingles: Disease FAQs for Providers
