Compressive Optic Nerve Lesions at the Optic Canal: Pathogenesis – Diagnosis – Treatment

1 Introduction.- 2 A Narrow Passage - Anatomic Considerations Topography of the Optic Canal Representing a Predilection of Nerve Compression with Various Pathologic Conditions.- 3 The Clinical Signs and Symptoms of Optic Nerve Compression and Clinical Disease Entities Masking Compressive Lesions.- 3.1 Ophthalmoscopic Findings. Visual Loss, Visual Field Defects, Afferent Pupillary Defect, Color Vision.- 3.2 Visual Evoked Potentials in Optic Nerve Compression.- 4 The Concept of Optic Nerve Compression by Dolichoectatic Arteries Revisited. The Literature and Why It Became Forgotten.- 5 Pneumosinus Dilatans - Rarely Diagnosed and Poorly Understood.- 6 CT Findings of Compressive Lesions at the Optic Canal.- 7 Pterional Approach for Microsurgical Decompression of the Optic Nerve.- 8 Intraoperative Findings in Patients with Intracanalicular Optic Nerve Compression.- 9 Selected Case Reports.- 10 Conclusions.- References.