neurocysticercosis is not only the most common parasitic disease in developing countries , but all over the world . patients present with varied manifestations depending on the location and stage of the parasites and the degree of parasitemia . we report a rare patient with combined ocular and cerebral neurocysticercosis who presented with acute painless monocular blindness prior to treatment with any antihelminthic drugs ( ahd ) . a 41-year - old chronic alcoholic and smoker male patient residing in western india presented with history of acute painless monocular vision loss in right eye over seconds while drinking at home . the symptoms were non - progressive since onset , and the patient sought consultation after 4 days due to lack of any improvement in symptoms . the patient was diagnosed as being hypertensive since 5 years , but was not compliant with his medications and reported bilateral parieto - occipital mild heaviness - type of evening headache since 5 years without any other symptom . there was no early morning worsening of his headache or any associated complaints of vomiting or visual blurring over the last few years . there was no previous history of any focal neurological deficits , transient ischemic attacks , amaurosis fugax , ischemic heart disease or diabetes , or similar history in family members . he was able to count fingers at 1 m by the right eye , and acuity was 6/12 in the left eye . color vision was normal in the left eye and was decreased appropriate to loss of acuity in the right eye . fundus examination revealed focal anterior displacement of retina in right macula suggestive of a cystic lesion . subsequently , full thickness retinal mapping was done which was suggestive of subretinal choroidal neurocysticercosis with greatly diminished visual field and retinal pigment epithelium / choroid disruption [ figure 1 ] . a brain magnetic resonance imaging ( mri ) was done which revealed multiple intracerebral neurocysticercosis in both hemispheres without any significant mass effect or hydrocephalus [ figures 2 and 3 ] while mri of the entire spinal cord was normal . the patient was advised surgical evacuation of the cyst followed by albendazole regime , but refused for surgery . ahd use in patients with ocular cysticercosis is associated with inflammatory response and retinal detachment leading to vision loss . he was thus started on treatment with only oral steroids given at 1 mg / kg dose and tapered off over 4 weeks . his visual acuity was static at 16 weeks of follow - up and is still not willing for surgical intervention . the patient does not report of any seizures till date and his electroencephalogram is repeatedly normal . ( a ) full retina thickness map showing disruption of the right ( od ) retina - choroid layers , and normal finding on left side ( os ) . ( b ) global rpe / choroid disruption map showing significantly impaired right side and normal left side magnetic resonance imaging ( mri ) brain axial view fluid attenuated inversion recovery ( flair ) images showing multiple cysts of neurocysticercosis in varying stages of development mri brain axial view post - gadolinium contrast images showing multiple cysts of neurocysticercosis in varying stages of development cysticercosis was previously seen primarily in developing countries with poor hygiene , sanitation and slaughterhouse facilities . it is now also seen in many western countries due to immigration from endemic areas and travel of local population to endemic areas . man is the definitive host and pigs are the intermediate host . human feces contain proglottids of the tapeworm , which contain the eggs within them . humans may accidentally become intermediate hosts by ingesting these eggs via feco - oral contamination and subsequent hematogeneous spread of the cysticercii leads to their dissemination in the body . brain , eyes , muscles and subcutaneous tissue are most commonly involved , and accordingly the symptoms vary . similarly , the cysts reach the highly vascular choroid via the hematogeneous route and there it grows in size in the subretinal space . ultimately it enters the vitreous to become an intra - vitreous cyst . overall , the most common presenting symptom of cysticercosis is seizures ( 79% ) , followed by headache ( 38% ) , focal deficits ( 16% ) and signs of raised intracranial tension ( 12% ) . . cerebral involvement may be either parenchymal or extra - parenchymal , with the former presenting most commonly as seizures . ocular cysticercii are intravitreal , subretinal , within the anterior chamber , or subconjunctival . among patients with orbital and ocular cysticercosis , most common presentation is proptosis , followed by subconjunctival cyst , subretinal cyst , papilledema , atypical optic neuritis , lid nodule and lastly intraretinal cyst . vision loss may be either due to intraocular cysts , due to chiasmal lesions causing optic nerve compression , due to retrochiasmal lesions like large parenchymal cysts or vasculitic cerebral infarcts , or due to hydrocephalus . the standard of care for cerebral neurocysticercosis is ahd ( albendazole or praziquantel ) with steroids and anticonvulsants . however , intraocular cysts if any should be removed prior to starting ahd , or else the tissue reaction to the dying parasite may lead to vitritis , retinal detachment and scarring leading to irreversible blindness . extraocular muscle cysticercosis also responds very well to ahd . in cases of isolated intraocular cysticercosis , timely surgical removal has been the treatment since the past 35 years or more . it is rare ( 10% ) for patients with ocular cysticercosis to have concomitant cerebral parenchymal cysts . disseminated neurocysticercosis presenting for the first time with acute monocular painless vision loss without any symptoms or signs suggestive of raised intracranial tension is extremely rare . there have been reports of post - ahd treatment acute monocular blindness , but we could not find any with such a presentation prior to treatment initiation in the literature till date . the vision loss in our patient was due to the retinal pigment epithelium / choroid disruption secondary to a submacular cysticercus . thus , in spite of having all risk factors for a vascular event and history suggestive of central retinal artery occlusion , we found a cause not thought of previously . thus , it is important to rule out ocular causes of vision loss , as also consider cysticercosis in all such cases in spite of no other history suggestive of the disease . also , the absence of seizures in spite of multiple cerebral parenchymal cysticercii is also uncommon considering that the most common presenting feature of neurocysticercosis is seizures .
neurocysticercosis , the most common parasitic infection of the nervous system , is known to affect the brain , eyes , muscular tissues and subcutaneous tissues . however , it is very rare for patients with ocular cysts to have concomitant cerebral cysts . also , the dominant clinical manifestation of patients with cerebral cysts is either seizures or headache . 
 we report a patient who presented with acute monocular painless vision loss due to intraocular submacular cysticercosis , who on investigation had multiple cerebral parenchymal cysticercal cysts , but never had any seizures . 
 although such a vision loss after initiation of antiparasitic treatment has been mentioned previously , acute monocular vision loss as the presenting feature of ocular cysticercosis is rare . 
 we present a brief review of literature along with this case report .