Vision loss after accidental methanol intoxication: a case report

BACKGROUND: Methanol intoxication is a dangerous situation because it often results in permanent problems such as visual deterioration, metabolic disturbances, neurological dysfunction, and even death. We present, to the best of our knowledge, the first case of irreversible bilateral blindness due to methanol intoxication caused by accidental ingestion of rubbing liquid. CASE PRESENTATION: A 49-year-old Greek man developed bilateral irreversible blindness after accidental methanol intoxication. He underwent complete ophthalmological examination, including electroretinogram, visual evoked potentials, multifocal-visual evoked potentials, and optical coherence tomography scan of the optic nerve. Complete laboratory evaluation, urine drug testing, neurological examination, and computed tomography scans were also performed. Visual acuity demonstrated no light perception bilaterally, pupils were semi-dilated and unreactive to light, while the retina was normal in both eyes. Electroretinogram was normal, while visual evoked potentials, multifocal-visual evoked potentials recording, and optical coherence tomography scanning of both optic nerve heads were pathological in both eyes. The neurological examination and the computed tomography scans did not reveal any abnormalities. The laboratory evaluation was normal and the urine drug test was negative for benzodiazepines, opiates, cocaine, amphetamines, salicylates, barbiturates, and phencyclidine. CONCLUSION: This is the first case report of methanol intoxication which documents both anatomical and functional abnormalities by means of optical coherence tomography and electrophysiological tests correspondingly. The ocular findings and the reported electrophysiological changes support the hypothesis that methanol affects photoreceptors, Müller cells, and the retrolaminar portion of the optic nerve.