In 2001, a ten-year-old boy suddenly suffered a severe headache associated with vomiting and refractory to ibuprofen. Fundus examination revealed incipient right papilledema. CT scan showed a right parasagittal occipital haemorrhage.
Subsequent angiographic studies revealed two malformation nests, one in the medial aspect of the right temporal lobe, with a volume of 7.5 cc, and another more posterior, located in the right occipital lobe, with a volume of 8 cc, also demonstrating peripheral angiogenesis in both lobes.
On neurological examination, a left homonymous hemianopsia was found by confrontation without other findings. The fundus examination, now distant from the acute bleeding episode, was normal in both eyes.
Between 2001 and 2005, the child underwent selective embolisation of the two malformation components, reducing the blood flow to the AVM afferents and the size of the AVMs. Subsequently, Gamma Knife radiosurgery was performed.
The patient has not suffered a recurrence of the haemorrhage but presents symptomatic photosensory epileptic seizures under medical treatment with valproic acid.
His electroencephalographic study showed interhemispheric asymmetry at the expense of the right cerebral hemisphere, compatible with right parieto-occipital structural brain involvement where sporadic localised epileptiform abnormalities have been observed in these regions.
Currently, the pharmacological dose of his medical treatment has been increased due to a resurgence of seizures and he comes to our department, referred by the neurology department, for assessment of intermittent diplopia, which has been present for four months, initially attributed to his epileptic seizures but which has not subsided despite the pharmacological increase in valproic acid.
On ophthalmological examination, the patient has VA of 0.6 (OD) and 0.5 (OI). Pupillary reflexes are normal. He has orthophoria, with normal ductions and versions. The Cover Test shows an exophoria of -3º -5º near and -5º -7º far. The fundus of both eyes is apparently normal. The refractive defect shows myopia of -0.75 dioptres in both eyes. A campimetric study was carried out (Humphrey, 24-2 threshold test) showing a highly congruent left homonymous hemianopic defect in both eyes, with a greater density of the defect in the lower left quadrant and macular respect. Optical correction was prescribed to the patient in order to improve his visual acuity and control his phoria.

