Blindness following hydrogen peroxide ingestion and recovery with hyperbaric oxygen therapy.

Hydrogen peroxide (HP) poisoning is rare but potentially life-threatening. It can cause tissue damage through oxygen emboli and reactive oxygen species (ROS). This is the first reported case of blindness caused by cerebral infarctions involving the visual pathway due to oxygen emboli from HP ingestion. A monocular patient presented with profound vision loss and no apparent pharyngeal mucosal injury following ingestion of commercial-grade (35 %) HP. CT imaging revealed gastric wall edema and gas in the portal venous system, suggesting gas emboli. Post-treatment MRI of the brain and orbits with and without contrast confirmed multifocal embolic infarcts along the visual pathway, and transcranial doppler studies identified moderate right-to-left shunting to explain the paradoxical emboli. The patient received hyperbaric oxygen therapy, resulting in a rapid improvement in visual acuity from hand motion to 20/20 and near-total resolution of visual field loss. Remarkably, this recovery occurred despite treatment initiation more than 24 h after symptom onset. This case emphasizes the importance of timely recognition and management of HP poisoning. In the authors' minds it also raised questions about the routine use of 100 % oxygen in hyperbaric therapy due to potential additional oxidative stress. It is the authors' opinion that further research should be done to validate treatment protocols and further interrogate possible risks associated with reactive oxygen species and oxygen toxicity.