Visual evoked potentials in a diagnosis of a visual pathway dysfunction of a child with an arachnoid cyst

The aim of this case report was to demonstrate the usefulness of the flash visual evoked potentials in monitoring the effects of intracranial hypertension in a preterm-born child with a congenital arachnoid cyst. At baseline, abnormalities were found in the right eye: exotropia and lack of foveal fixation. Visual acuity was not achieved. Pupillary responses were normal in both eyes. There was no evidence of nystagmus. Flash visual evoked potentials were normal and equal in both eyes. When repeated one year later the signal had deteriorated in both eyes; the peak times of N2 and P2 had increased. The increased VEP latencies were the only ocular signs noted. After referral to neurosurgery, intracranial hypertension was found and a shunt was performed. Flash visual evoked potentials may be a valuable test in monitoring patients with arachnoid cysts.