Herpes Zoster Ophthalmicus

Herpes zoster ophthalmicus  HZO, also known as Ocular Shingles, is a painful dermatomal rash around the eye region and forehead caused by the reactivation of the Varicella Zoster Virus (VZV). It affects the trigeminal nerve of the ophthalmic division and eventually spreads to the other structures of the eye. The first division of the trigeminal nerve is the most common site for the development of acute herpes zoster.

Varicella-zoster virus manifests at two different stages in humans. At primary level the virus causes chicken pox after which it remains dormant for several years and reappears as herpes zoster later in the patient’s life. Aging, poor nutrition and low immunity are some of the risk factors that leads to the outbreak of Herpes zoster ophthalmic us (HZO).

Symptoms

HZO begins with flu-like symptoms including fever, Myalgia, and malaise for nearly a week. Typically, patients then develop tingling sensation and painful rash on the forehead and ocular symptoms such as eyelid edema; conjunctival, episcleral and circumcorneal conjunctival hyperemia; corneal edema and light sensitivity. All these symptoms are unilateral - occurring on one side of the face. 

Diagnosis

Herpes zoster ophthalmicus (HZO) is diagnosed clinically by mere observation of the symptoms. During a clinical visit, the ophthalmologist conducts a detailed examination of  visual acuity, visual fields, extra ocular movements, pupillary response, corneal function, Intraocular Pressure and anterior chamber. Doctor also makes a note of past history of chicken pox infection along with clinical examination. Viral culture, direct immunofluorescence assay, or Polymerase chain reaction (PCR) may also be used to confirm the diagnosis. Any signs of Hutchinson disease strongly indicates ocular complications such as inflammation and corneal denervation and forms the basis for diagnosis of herpes zoster ophthalmicus.

Treatment

Herpes zoster ophthalmicus is a medical emergency and should be treated promptly to avoid vision loss. The disease leads to many ocular conditions such as dermatitis, corneal pseudo-dendrites, uveitis, retinitis, and in rare cases it also causes cranial nerve palsies. Oral anti viral medicines like Acyclovir and Famcyclovir play a major role in treating herpes zoster ophthalmicus. Atropine eye drops are also prescribed to alleviate the painful symptoms. In case keratitis develops, Corticosteroid drops along with Cycloplegics (eye drops to induce ciliary muscle paralysis) may also be considered.