Herpes zoster ophthalmicus (HZO) is a form of shingles that affects the eye and the skin around it. It happens when the varicella-zoster virus, the same virus that causes chickenpox, reactivates in a specific branch of the nerve that supplies sensation to your face. Around 50% to 70% of people with shingles in this area develop some form of eye involvement, and roughly 1 in 10 experience permanent vision loss.
How the Virus Reaches the Eye
After you recover from chickenpox, the varicella-zoster virus doesn’t leave your body. It goes dormant in nerve clusters along your spine and skull, where it can remain silent for decades. HZO occurs when the virus reactivates specifically in the ophthalmic division of the trigeminal nerve, the first of three branches that carry sensation from your face to your brain. This branch supplies your forehead, upper eyelid, and the surface of the eye itself.
When the virus wakes up, it travels along this nerve fiber toward the skin and eye tissues it connects to, causing inflammation and damage along the way. That’s why the rash and pain from HZO follow a very specific pattern: they appear on one side of the forehead and around one eye, stopping sharply at the midline of the face. The average age at first episode is 68, though it can occur in adults as young as their late twenties. Older age, immunosuppression, diabetes, and lupus all raise the risk.
What It Feels Like
HZO typically starts with a prodrome, a warning phase before any visible rash appears. You might notice burning pain, tingling, or unusual skin sensitivity on one side of your forehead. Headache on the same side is common. This phase can last one to several days, and during this time, HZO is easy to mistake for a migraine or sinus problem.
Then the rash appears: clusters of small, fluid-filled blisters on the forehead, upper eyelid, and sometimes the side of the nose, always limited to one side. The pain can be intense and often feels disproportionate to how the rash looks. Some people describe it as a deep, burning ache; others feel sharp, stabbing sensations or extreme sensitivity where even a light breeze across the skin hurts.
The Hutchinson Sign
One clue doctors watch for is blisters on the tip or side of the nose. This is called the Hutchinson sign, and it matters because the same nerve branch that supplies the nose tip also supplies the eyeball. Research from the American Academy of Ophthalmology found that this sign carries a six-fold increased likelihood of eye involvement, with 89% specificity. In practical terms, if you have blisters on your nose tip, there’s a very high chance the virus is also affecting your eye. But the absence of this sign doesn’t guarantee safety: about half of people with eye involvement never develop it.
How HZO Damages the Eye
The virus can inflame nearly every structure in and around the eye. The most common complication is keratitis, inflammation of the cornea, which can cause pain, light sensitivity, tearing, and blurred vision. The cornea may develop tiny ulcers or lose sensation entirely, making it vulnerable to further injury because you can’t feel when something is wrong.
Uveitis, inflammation inside the eye, is another frequent problem. It can raise pressure within the eye and, if it persists or recurs, contribute to glaucoma. A study in the American Journal of Ophthalmology found that uveitis was one of the strongest predictors of severe vision loss, increasing the risk nearly fivefold.
Among people who develop HZO, about 9.6% end up with moderate permanent vision loss, and 3.6% experience severe loss. Corneal scarring accounts for 94% of these cases. Corneal perforation and secondary glaucoma make up the rest. Older age, immunosuppression, poor vision at the time of diagnosis, and uveitis all increase the risk of a worse outcome.
Postherpetic Neuralgia
Even after the rash heals and the eye complications are managed, about 1 in 5 people with shingles develop postherpetic neuralgia: chronic nerve pain that persists for months or sometimes years in the area where the rash appeared. With HZO, that means ongoing pain across the forehead, around the eye socket, or along the scalp. Ophthalmic involvement is itself a risk factor for this complication, on top of older age and the severity of the initial episode. The pain can range from a constant dull burn to sharp jolts triggered by light touch.
How It’s Diagnosed
Most cases are diagnosed on sight. The combination of a one-sided forehead rash with blistering, eye redness, and pain in a characteristic nerve pattern is distinctive enough for a clinical diagnosis. When the presentation is unusual or the rash hasn’t fully developed, a PCR test can confirm the virus. This involves swabbing fluid from a blister or cells from the base of a lesion. PCR is the most reliable lab method. Blood tests for antibodies have limited usefulness for confirming active shingles and are generally only used when no suitable skin sample is available.
Because eye involvement is so common with HZO, an eye exam with corneal staining is standard even if your vision seems fine. This exam can reveal subtle corneal damage that isn’t obvious from symptoms alone.
Treatment and What to Expect
Antiviral medication is the cornerstone of treatment, and timing matters. Treatment is most effective when started within 48 hours of the rash appearing. The standard course is an oral antiviral taken three times daily for seven days. Starting treatment quickly reduces the severity of the rash, lowers the risk of eye complications, and may reduce the chance of lingering nerve pain. Beyond 72 hours, the benefit of antivirals is less well established.
If the eye is involved, treatment expands to include anti-inflammatory drops, pressure-lowering drops if needed, and sometimes lubricating drops to protect a cornea that has lost sensation. Some people need ongoing eye care for weeks or months, particularly if uveitis recurs or corneal healing is slow. Follow-up appointments are important because complications like elevated eye pressure can develop quietly, without obvious symptoms, well after the initial infection has cleared.
Prevention With Vaccination
The recombinant shingles vaccine (Shingrix) is the most effective way to prevent HZO. Its overall adjusted effectiveness for preventing herpes zoster ophthalmicus specifically is 89.1%. The vaccine is recommended for adults 50 and older, as well as immunocompromised adults 19 and older, and is given as two doses spaced two to six months apart. Even people who have had shingles before can benefit, since recurrence is possible.
Prior chickenpox infection or an older shingles vaccine does not provide the same level of protection. Given that HZO incidence has been rising steadily over the past two decades, increasing by roughly 1.1 cases per 100,000 person-years annually, vaccination remains the single most impactful step for reducing your risk.