herpes zoster ophthalmicus ( hzo ) is a disease in which varicella - zoster virus ( vzv ) replicates and produces neural inflammation and epidermal facial lesions in areas supplied by sensory branches of the ophthalmic division of the trigeminal nerve . extraocular muscle palsies are rare complications occurring in seven to 31% of hzo , usually seen in elderly patients and characterized by self - limited resolution . we present herein a case of hzo complicated by sixth nerve palsy and we discuss the etiology of this complication . treatment commenced with oral acyclovir ( 2 g daily ) 1 week following symptom onset . on physical examination , cicatricial lesions were observed with crusts involving the left hemiface , and limited left eye abduction [ figure 1 ] . visual acuity was 4/10 with conjunctival hyperemia , superior superficial punctuate keratitis ( spk ) , and normal intraocular pressure ( iop ) . pupil size was 5 mm , with prompt pupillary light reflex , a posterior intraocular lens , and a normal fundus of the left eye . in the right eye , corrected visual acuity along with unremarkable examination of the anterior and posterior segments . cicatricial lesions on the left hemiface and limited abduction the hess chart demonstrated that abduction of the left eye was severely limited [ figure 2 ] . severely limited abduction on the hess chart vesicular eruptions resolved within 1 week , although diplopia was still present . six weeks later , abducens nerve palsy had improved without additional treatment [ figures 3 and 4 ] . clinical improvement of the abducens nerve palsy improvement of the abducens nerve palsy on the hess chart herpes zoster ( hz ) is a common disease mainly affecting elderly patients due to reduction in the level of t - cell immunity to vzv following initial infection and senescence . hz occurs by reactivation of latent virus in ganglions following primary infection with varicella zoster ( chicken pox ) and occurs mostly in thoracic and cranial sensory ganglia . in addition to sensory neurons , hz may also affect motor neurons in rare cases . when the ophthalmic division of the trigeminal nerve is affected , the condition is referred to as hzo which occurs in 10 - 25% of hz with 50% of these cases infecting the eye . ocular signs can be acute , chronic , and relapsing ; and include conjunctivitis , keratitis ( commonly epithelial followed by nummular and disciform ) , episcleritis , scleritis , uveitis , secondary glaucoma , cataract , and retinal necrosis . hzo may cause extraocular muscle palsies of the third , fourth , and sixth cranial nerves in 7 - 31% of patients . the third nerve is the most common site among them and the fourth the least . complete ophthalmoplegia is a very rare complication of hzo ; only few cases have been reported in the literature . the extraocular muscle palsies usually appear 2 - 4 weeks after the rash , but sometimes occurs simultaneously with the rash or more than 4 weeks later . the pathogenesis of ophthalmoplegia is controversial and several mechanisms have been postulated : the first is a direct cytopathic effect from the virus itself on the surrounding neural tissue . a fourth theory suggests that the vzv activates another latent neuropathic virus within the brain . kreibig et al . , postulated that the extraocular palsies were due to perivasculitis - myositis , rather than to a neural origin . muscle ischemia remains a strong possibility , as does a combination of cortical nerve and muscle inflammation . therefore , isolated abducens nerve palsy might be caused by circumscribed orbital myositis or a lymphocytic cranial motor neuropathy . the therapeutic goal is to limit the severity of acute and chronic pain , hasten the healing process , and reduce the chances of dissemination . treatment consists of administration of an antiviral agent that crosses the blood - brain barrier ( acyclovir , famciclovir , valacyclovir ) . antiviral therapy is substantially more effective if begun within the first 72 h of rash onset . antiviral treatment induces prompt resolution of skin lesions , diminishes viral shedding , lessens lesion formation , and decreases corneal and uveal involvement . treatment with nucleotide analogues may prevent the direct cytotoxic effect of the virus , the immune response of the surrounding neural tissue , and the initiation of a secondary vasculitis by inhibiting initial viral replication limiting duration and severity of infection . the use of systemic corticosteroids may be effective to prevent occlusive vasculitis , but there is a risk of suppressing the immune system in viral infections with corticosteroid use . there are different suggestions about treatment of paralytic lesions that complicate hz . some authors have examined the effectiveness of antiviral therapy and adrenal cortex hormones . as the paralytic lesions tend to resolve spontaneously , effects of specific treatment are unclear . a live attenuated hz vaccine for individuals older than 60 years has recently been proposed . the efficacy of the vaccine in preventing hz is 70% for subjects 50 - 59 years of age , 64% for persons 60 - 69 years of age , 41% in subjects aged 70 - 79 years , and 18% in individuals aged > 80 years . however , there is a risk of developing hz in patients who receive the vaccine who have never been infected with vzv . it was reported that duration of diplopia associated with ocular motor palsy was between 2 and 23 months . ophthalmoplegia as a complication of hzo may have various origins ; the efficacy of antiviral agents and corticosteroids in treating the oculomotor palsy remains controversial since the spontaneous recovery of palsy has been reported .
the extraocular muscle palsies associated with herpes zoster ophthalmicus ( hzo ) are transient , self - limiting conditions , usually seen in elderly patients . 
 there are different treatment recommendations for paralytic complications , but prognosis has generally reported to be favorable . a 75-year - old male patient presented with diplopia . 
 clinical history revealed left facial vesicular eruptions and pain treated by oral aciclovir 1 week following symptom onset . on examination , we observed cicatricial lesions with crusts involving left hemiface , a limitation in abduction of the left eye , and a superficial punctuate keratitis ( spk ) with decreased visual acuity ( 4/10 ) . examination of the right eye was unremarkable . 
 hess screen test confirmed left six nerve palsy .