Shingles in the Eye: Herpes Zoster Ophthalmicus Explained

A one-sided, blistering rash on your forehead is never just a rash. If shingles appears anywhere near the eye, it has a name of its own, herpes zoster ophthalmicus (HZO), and it earns that name by being one of the few rashes that can threaten your sight. I treat the eye complications of shingles regularly at the Queensland Eye Institute, and the difference between a smooth recovery and months of trouble often comes down to how quickly treatment starts.

What is herpes zoster (shingles)?

Herpes zoster is the medical name for shingles. If you’ve had chickenpox, the varicella zoster virus never truly left: it has been lying dormant in your nerves ever since, and years or decades later it can reactivate, typically as immunity dips with age, illness or stress. When it wakes, it travels along a single nerve and erupts as a painful, blistering rash in that nerve’s territory, almost always on one side of the body.

Despite the confusingly similar names, shingles is not the same as herpes simplex, the cold-sore virus, although both can affect the eye. I’ve written a separate guide to the difference between shingles and herpes if you want that untangled properly.

What is herpes zoster ophthalmicus?

Herpes zoster ophthalmicus is shingles picking the wrong nerve. Studies suggest between one in ten and one in five cases of shingles involve the nerve that supplies the forehead, upper eyelid and eye. It usually announces itself before the rash arrives: a day or two of burning, tingling or one-sided headache over the brow, sometimes with fever or fatigue. Then come the blisters, scattered across one side of the forehead and scalp, stopping sharply at the midline, often with a puffy upper lid.

The rash itself will heal. The reason HZO deserves respect is what can happen behind it: in published series, roughly half of cases develop involvement of the eye itself without prompt antiviral treatment.

Hutchinson’s sign: the blister on the nose

One small detail changes the risk calculation considerably. The nerve branch that supplies the tip and side of the nose also supplies the eye itself, so a blister on the nose, called Hutchinson’s sign, is a strong signal that the eye is likely to become involved. It’s one of the first things I look for when a patient walks in with a facial rash. Spots on the nose mean an eye examination is needed promptly, even if the eye still feels normal.

What shingles can do to the eye

The virus and the inflammation that follows it can affect almost every structure at the front of the eye:

• The cornea (keratitis): inflammation and swirling surface changes that blur vision and can scar if untreated
• The iris (uveitis): deep ache, light sensitivity and redness from inflammation inside the eye
• Eye pressure: inflammation can push the pressure up, which needs its own treatment
• The corneal nerves: shingles can leave the cornea numb (a neurotrophic cornea), and a numb cornea heals poorly and needs long-term care
• Rarely, the retina or optic nerve, which is sight-threatening and treated urgently

Severe corneal scarring from HZO is one of the conditions that can eventually need corneal transplant surgery, which is precisely the outcome early treatment aims to avoid. Many patients also experience lingering nerve pain after the rash settles, called postherpetic neuralgia.

Why the first 72 hours matter

Antiviral tablets (such as valaciclovir or famciclovir) substantially reduce the eye complications of shingles, and they work best when started within 72 hours of the rash appearing. That makes the plan simple: a one-sided forehead rash means seeing your GP that day, not next week. If the eye becomes involved, treatment is tailored to which structures are inflamed, and may include anti-inflammatory drops. Those drops do real good in the right setting and real harm in the wrong one, so they belong under ophthalmic supervision rather than guesswork.

HZO also plays a long game: eye inflammation can flare again months or even years after the rash has gone, so if your eye was involved, some ongoing monitoring is part of proper care.

Can shingles in the eye be prevented?

Largely, yes. The shingles vaccine (Shingrix) substantially reduces the risk of shingles and of postherpetic neuralgia, and in Australia it is free under the National Immunisation Program for eligible groups, including people aged 65 and over. If shingles isn’t something you’ve discussed with your GP, it’s a conversation worth having, because the best case of HZO is the one that never happens.

A rash near your eye? Act today

If you develop a one-sided blistering rash on your forehead or nose, see your GP the same day for antivirals. And if your eye becomes red, achy, watery, light-sensitive or blurry, or there are blisters on your nose, you need an eye examination promptly. If you need to be seen the same day, phone the clinic on (07) 3239 5000 rather than waiting on the online form, and outside clinic hours a hospital emergency department is the right place. Caught early, shingles in the eye is very manageable, and that’s exactly how I’d like to keep it.