Bilateral Optic Neuropathy Associated with Acute Inhaled Marijuana Use: Case Report and Review of the Literature

Marijuana is the most commonly used federally illegal drug in the United States. Acute marijuana use is associated with several cardiovascular and neuropsychological adverse effects. Ocular complications of marijuana abuse are very rare. Herein, we present the first report of bilateral optic neuropathy following smoking marijuana. A 28-year-old man presented to the emergency room with sudden onset of bilateral blurring of the inferior visual field 8 h after smoking marijuana. His best-corrected visual acuity was 20/30 in the right eye and 20/20 in the left eye. Fundus examination revealed blurring of the optic disc margins in both eyes and a splinter haemorrhage in the right eye. Bilateral inferior visual field defects were detected with greater severity on the right side. Optical coherence tomography confirmed the diagnosis of bilateral optic neuropathy. A urine drug screen test was positive for tetrahydrocannabinol, which is the primary active ingredient in cannabinoids. The rest of the neurological examination and imaging were normal. The patient was treated with intravenous corticosteroids and an anti-platelet drug. His vision recovered to 20/20 in both eyes, with complete resolution of the field defect over a follow-up of 6 months. Optic neuropathy following marijuana abuse is unusual. The results of our report emphasise the need for awareness of marijuana-associated optic neuropathy as part of ocular adverse effects of marijuana intoxication.