A 18-year male was presented with diplopia on looking toward the left since five days. There was no headache, vomiting, drooping of eyelid, visual impairment, and pain around the eye, diurnal variation or weakness of limbs. Examination revealed no ptosis, nystagmus; pupils were bilaterally symmetrical in size & reactive to light. Fundus examination was normal. Extra ocular movements on both sides were normal except restriction of adduction of right eye. The rest of the neurological examination was normal. The investigations revealed normal routine hemogram including erythrocyte sedimentation rate and biochemistry. Enzyme-linked immunosorbent assay (ELISA) for cysticercus was positive both in cerebrospinal fluid examination (CSF) and serum. The other parameters of CSF were normal. Computerized tomogram of orbit revealed swollen medial rectus with ring lesion. Patient received albendazole therapy (15mg/kg for 4 weeks) under cover of steroids and started showing improvement in diplopia within a week.

Figure 1

Figure: CT scan of orbit showing cysticercal cyst in medial rectus, which resolved after treatment.

The CT scan was repeated after 8 weeks revealed disappearance of lesion except swollen medial rectus of right eye. A high index of suspicion should be entertained for extra ocular muscle cysticercosis, especially in cases of acquired ocular motility disorder.