Pneumosinus Dilatans: Two Rare Cases of Primary Bilateral Compressive Optic Neuropathy

Pneumosinus Dilatans is a rare phenomenon characterized by hyper-pneumatization of one or more paranasal sinuses without erosion of sinus bone walls. It most commonly involves the frontal sinus, followed by the sphenoid sinus. Patients may be asymptomatic; however, when the sphenoid sinus is involved, visual symptoms can occur. In this report, we present two rare cases of bilateral optic atrophy in young individuals caused by hyperpneumatisation of the sphenoid sinus, leading to bilateral compressive optic neuropathy. This report highlights the importance of a thorough approach to progressive optic neuropathy, including appropriate neuroimaging, in diagnosing this rare cause of compressive neuropathy.