INTRODUCTION: Johan Georg Raeder (1889-1959) was the most eminent Norwegian ophthalmologist in the early decades of the last century. Raeder made significant contributions to our current understanding of glaucoma. He is remembered for a syndrome he described, that of trigeminal nerve neuralgia and/or paresis and incomplete Horner's syndrome (oculopupillary sympathetic paresis). DISCUSSION: Here, Raeder's biography, scientific contributions, and a thorough review of his original report on paratrigeminal sympathetic paresis are presented. Raeder's syndrome may reflect a lesion of the middle cranial fossa, which involves oculopupillary sympathetic fibers that originate from the internal carotid artery plexus and travel with the trigeminal and oculomotor nerves.