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  • Updated 03.02.2026
  • Released 07.14.1997
  • Expires For CME 03.02.2029

Cortical blindness

Author
Sangeeta Khanna MD
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Editor
Jonathan D Trobe MD
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Cite this article

Introduction

Overview

Cortical blindness is often used to refer to visual loss due to bilateral lesions of the geniculocalcarine pathways. It is used interchangeably with the term “cerebral blindness” in this article. Patients are often unaware of the extent of their visual loss (often confabulating their responses), a phenomenon called “Anton syndrome.” Etiologies of cortical blindness are numerous and diverse.

Key points

• Cortical blindness can be confused with nonorganic visual loss because the eye examination, including pupillary responses, is normal. Nonorganic (ie, psychogenic, functional) visual loss should be considered as a diagnosis of exclusion but can be suggested by examination findings that violate physiological patterns of visual loss.

• Cortical blindness may be overlooked because symptoms of visual loss may not be expressed or may even be denied by the patient.

• Brain MRI is an important diagnostic test to determine the cause of cortical blindness, but not all causes produce MRI abnormalities.

Historical note and terminology

"Cortical blindness" refers to visual loss due to bilateral dysfunction of the occipital visual cortex (“striate cortex” or V1). Some patients will exhibit a lack of awareness of the extent of visual loss. This remarkable clinical state is termed "Anton syndrome" in reference to Gabriel Anton, who described this phenomenon in 1899. Anosognosia, first used by Babinski in 1914, defines a lack of knowledge of the disease. Anton syndrome (sometimes referred to as Anton-Babinski syndrome) is a form of visual anosognosia. For lesions not isolated to the cortex, including the subcortical visual pathways, the term "cerebral blindness" may be more appropriate. In strictest terms, cortical blindness is a specific subtype of cerebral blindness. The term "cortical visual impairment" has been applied in the pediatric population when visual deficits are incomplete. Because the term "cortical blindness" continues to be in common use, it is retained in this article to include vision loss caused by any insult to the geniculocalcarine visual pathway.

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