Archive | February 2011

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Chapter 197 – Disorders of Supranuclear Control of Ocular Motility

Chapter 197 – Disorders of Supranuclear Control of Ocular Motility   PATRICK J.M. LAVIN SEAN P. DONAHUE           DEFINITION • Loss of voluntary saccades (fast) and pursuit (slow) eye movements may result from interruption of neural pathways that carry commands from the cerebral cortex to the ocular motor nuclei in the […]

Chapter 196 – Retrochiasmal Pathways, Higher Cortical Function, and Nonorganic Visual Loss

Chapter 196 – Retrochiasmal Pathways, Higher Cortical Function, and Nonorganic Visual Loss   ANDREW W. LAWTON           DEFINITION • The retrochiasmal pathways consist of parallel streams of information diverted to appropriate areas of the brain for identification, storage, and retrieval.   KEY FEATURES • Lesions of numerous areas of the brain […]

Chapter 195 – Optic Chiasm, Parasellar Region, and Pituitary Fossa

Chapter 195 – Optic Chiasm, Parasellar Region, and Pituitary Fossa   RICHARD M. RUBIN ALFREDO A. SADUN ALFIO PAVA           DEFINITION • Loss of vision and visual field related to involvement of the chiasm itself, its blood supply, or adjacent optic nerve or optic tract by tumor or other processes.   […]

Chapter 194 – Traumatic Optic Neuropathies

Chapter 194 – Traumatic Optic Neuropathies   THOMAS C. SPOOR           DEFINITION • Optic nerve damage after cranio-orbital trauma.   KEY FEATURES • Decreased visual acuity. • Relative afferent pupillary defect. • Visual field defects.   ASSOCIATED FEATURES • Optic nerve infarction. • Orbital or optic nerve sheath hematoma. • Central […]

Chapter 193 – Prechiasmal Pathways—Compression by Optic Nerve and Sheath Tumors

Chapter 193 – Prechiasmal Pathways—Compression by Optic Nerve and Sheath Tumors   THOMAS C. SPOOR           DEFINITION • Optic nerve dysfunction as a result of compression by tumor or aneurysm anywhere along the nerve’s course from globe to chiasm.   KEY FEATURES • Progressive visual field loss. • Relative afferent pupillary […]

Chapter 192 – Hereditary, Nutritional, and Toxic Optic Atrophies

Chapter 192 – Hereditary, Nutritional, and Toxic Optic Atrophies   ALFREDO A. SADUN SEVGI GURKAN           DEFINITION • Leber’s hereditary optic neuropathy, which arises from an inherited point mutation in mitochondrial DNA, manifests in young adulthood as a distinctive heredodegenerative optic neuropathy. • Nutritional deficiency states, particularly those that involve the […]

Chapter 191 – Ischemic Optic Neuropathy, Diabetic Papillopathy, and Papillophlebitis

Chapter 191 – Ischemic Optic Neuropathy, Diabetic Papillopathy, and Papillophlebitis   ANTHONY C. ARNOLD           DEFINITION • Acute, painless optic neuropathy occurring predominantly in patients over 50 years of age. • Additional acute pathologies of the optic disc may be associated with diabetes and venous congestion.   KEY FEATURES • Optic […]

Chapter 190 – Inflammatory Optic Neuropathies and Neuroretinitis

Chapter 190 – Inflammatory Optic Neuropathies and Neuroretinitis   LAURA J. BALCER ROY W. BECK           DEFINITION • Optic neuritis refers to inflammation of the optic nerve. Such inflammation may spare the optic disc (retrobulbar optic neuritis) or may cause optic disc swelling (papillitis).   KEY FEATURES • Abrupt vision loss. […]

Chapter 189 – Papilledema and Raised Intracranial Pressure

Chapter 189 – Papilledema and Raised Intracranial Pressure   ALFREDO A. SADUN           DEFINITION • Optic disc edema, usually bilateral, that results from increased intracranial pressure.   KEY FEATURES • Blurring of the optic disc margins. • Anterior extension of the nerve head. • Venous congestion of arcuate and peripapillary vessels. […]

Chapter 188 – Congenital Optic Disc Anomalies

Chapter 188 – Congenital Optic Disc Anomalies   MICHAEL C. BRODSKY           DEFINITION • Unusual configurations of the optic disc(s) typically present since birth.   KEY FEATURE • Small, pale, or unusually shaped optic discs may reflect mere curiosities or significant anomalies associated with visual defects.   ASSOCIATED FEATURE • Abnormalities […]