Leber's hereditary optic neuropathy precipitated by tadalafil use for erectile dysfunction.

Leber's hereditary optic neuropathy (LHON) is an inherited condition leading to bilateral centrocaecal scotoma. Phosphodiesterase type-5 (PDE5) inhibitors such as tadalafil are widely used for male erectile dysfunction. We present a case of a middle-aged male whose LHON presented acutely following tadalafil use. It is postulated that this is due to alteration in the optic nerve head perfusion.