Orbital infection in association with sinusitis is an emergency. It may cause visual disturbances, and in rare cases even permanent blindness by affecting the optic nerve. We report an unusual case of acute sinusitis that was complicated by irreversible visual loss in a young patient. As there is increasing evidence that respiratory viruses play an important role in the pathogenesis of acute community acquired sinusitis and spontaneous healing with only symptomatic treatment is common, the use of antibiotics in the treatment of acute sinusitis may not be needed in all cases. If the general policy to use antibiotics in acute sinusitis will be changed to more restrained and expectant, we have to be even more aware of these nowadays rare complications.