Herpes Zoster Ophthalmicus (HZO) is a serious condition resulting from the reactivation of the varicella-zoster virus (VZV), the same virus that causes chickenpox and shingles. This specific form of shingles occurs when the virus travels along the ophthalmic division of the trigeminal nerve, which supplies sensation to the eye, eyelid, forehead, and nose. The proximity of this viral activity to the eye makes it a potentially sight-threatening disease, accounting for up to 10% of all shingles cases. While a rash is the most visible sign, the condition is defined by this viral involvement of the nerve pathway.
Early Warning Signs and Sensations
Shingles around the eye often begins with a distinct feeling of discomfort known as the prodromal phase, occurring two to five days before any visible rash. Systemic symptoms like fatigue, malaise, or a low-grade fever may also be present.
The primary early symptom is an intense, localized neurological sensation along one side of the forehead, scalp, or upper eyelid. Patients describe this as a burning, throbbing, shooting, or tingling pain. This pain is strictly unilateral, confined to one half of the face following the path of the affected nerve.
The Characteristic Skin Rash Appearance
The definitive visual sign is the characteristic dermatological rash, which follows a predictable progression confined to the ophthalmic nerve’s distribution. Initial signs are patches of redness (erythematous macules) that quickly develop into raised bumps (papules). Within days, these progress into clusters of clear, fluid-filled blisters (vesicles) on the forehead, scalp, or upper eyelid.
The rash remains strictly unilateral, respecting the midline of the face, and often causes significant swelling of the eyelid and surrounding periorbital tissue. Over about a week, the vesicles become cloudy and pustular before rupturing, weeping, and crusting over. The presence of vesicles on the tip or side of the nose, known as Hutchinson sign, is a significant indicator. Because the nasociliary nerve supplies both the nose tip and internal eye structures, this sign signals a higher risk of internal ocular involvement.
Signs of Internal Ocular Complications
The most dangerous aspect is the spread of the virus to internal eye structures, occurring in up to 50% of untreated cases. Signs of internal spread include severe, persistent eye redness, often due to inflammation of the conjunctiva or sclera. Inflammation of the iris and ciliary body (uveitis or iritis) is a serious complication causing pain, light sensitivity (photophobia), and blurred vision.
The cornea, the clear front surface of the eye, is frequently affected, leading to keratitis. This manifests as clouding, swelling, or lesions on the corneal surface, causing a foreign body sensation and decreased visual acuity. Other signs include a sudden increase in intraocular pressure, which can lead to secondary glaucoma, or, rarely, inflammation extending to the retina (acute retinal necrosis). These complications threaten long-term vision and require specialized management.
Immediate Medical Consultation and Treatment
Immediate medical attention is necessary upon suspecting shingles near the eye due to the high risk of serious and permanent vision loss. Prompt treatment involves oral antiviral medication (e.g., acyclovir, valacyclovir, or famciclovir). To maximize effectiveness and reduce ocular complications, antiviral therapy should be initiated within 72 hours of the rash’s first appearance.
An ophthalmologist must be consulted urgently, even if the external rash appears mild or the patient reports no visual symptoms. This specialized consultation is required to examine the internal structures of the eye for subtle signs of viral spread, such as inflammation or elevated eye pressure. Early treatment significantly reduces the rate of ocular complications, potentially lowering the risk of eye involvement from 29% to as low as 2%.