ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
A form of BLINDNESS caused by destruction or DENERVATION of the PRIMARY VISUAL CORTEX. Vascular, traumatic, and neoplastic lesions that affect the primary visual cortex (also called STRIATE CORTEX; BRODMANN'S AREA 17; V1) directly or by destroying its afferents, are the most common causes of cortical blindness. As the right visual HEMIFIELDS of both eyes are represented in the LEFT HEMISPHERE, and vice versa, destruction of primary visual cortex in one hemisphere causes a partial cortical blindness restricted to the contralateral visual hemifield, while bilateral destruction causes a complete cortical blindness. The strict TOPOGRAPHY of the representation in V1 accounts for the precise location of the different types of visual field defects that include HEMIANOPIA and QUADRANTANOPIA, with or without MACULAR SPARING, and central, paracentral, or peripheral SCOTOMAs. The extent, position in the field, and density of the defects is assessed with dynamic and/or static PERIMETRY; density refers to the depth or completeness of the visual loss in the defect. While a relative defect allows some residual visual perception, an absolute one is characterized by an absence of all conscious vision. Zones of relative loss often surround absolute scotomata. Even in absolute cortical blindness, unconscious residual visual functions (see BLINDSIGHT) remain.
Postoperative blindness
Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor in Manual of Neuroanesthesia, 2017
Cortical blindness: The causes of cortical blindness include global or focal ischemia, cardiac arrest, hypoxemia, vascular occlusion, intracranial hypertension, exsanguinating hemorrhage, and emboli.3 Patients may present with the signs of stroke in the parieto-occipital region and agnosia, that is, inability to interpret sensory stimuli. The vision might recover within days, but impairment in spatial perception and in the relationship between sizes and distances may remain for a longer period.20
Visual cortex
Fiona Rowe in Visual Fields via the Visual Pathway, 2016
A small minority of patients with cortical blindness behaves as though they are not aware of their deficit and insist that they can see (Hartmann et al. 1991). This is termed Anton’s syndrome. Patients have normal optic disc appearance, pupil function and extraocular muscle movement but no response from the lid reflex in response to light or danger.
Bilateral occipital lobe infarct neglect deficit (BLIND) syndrome
Published in Journal of Community Hospital Internal Medicine Perspectives, 2021
S Shanmugam, HL Haver, SM Knecht, R Rajjoub, O Ali, R Chow
Aldrich et al. notes that cortical blindness can be caused by multiple etiologies, including cerebrovascular infarct, surgery such as coronary artery bypass, aortic valve replacement, laryngeal surgery, craniotomy and cerebral angiography [1]. Mechanisms of cerebral dysfunction during surgery or angiography are usually described as an event of anoxia, hypoperfusion, or hemorrhage leading to infarction of the cerebral tissue [1]. Post-traumatic contusions, progressive multifocal leukoencephalopathy, adrenoleukodystrophy and seizures are nonvascular etiologies of cortical blindness that can present with findings consistent with Anton Syndrome [2]. For management, it is essential to distinguish vascular from nonvascular etiologies in patients with suspected Anton Syndrome. Vascular causes usually imply poor prognosis, while visual anosognosia and vision deficits due to nonvascular causes may improve and sometimes resolve completely [1,2,5].
A Scoping Review of Intervention for Pediatric Cerebral Visual Impairment: Calling All Pediatric Occupational Therapists
Published in Occupational Therapy In Health Care, 2023
Kathleen Weden, Dawn K. DeCarlo, Elizabeth Barstow
A pilot search was first conducted and terms that were never used (neurological visual impairment, occipital blindness, central blindness, central visual impairment, occipital visual impairment) were removed in subsequent search compositions. The remaining diagnostic terms that were used included: cerebral visual impairment, cortical visual impairment, and central visual impairment (Table 1). One search term that required unique consideration was the term “cortical blindness”. We initially included cortical blindness because this was an early term used for cerebral visual impairment. But beginning in the 1980s cortical blindness was differentiated as a term to indicate a total loss of vision (Drymalski, 1980), a condition different from cerebral visual impairment. Therefore, we chose to remove the term cortical blindness from our search terms.
Consent for post-operative visual loss in prone spinal surgery: aligning clinical practice with legal standards
Published in British Journal of Neurosurgery, 2018
Fay Greenway, Isabel Tulloch, James Laban
Cortical blindness is due to ischaemia or extreme hypoperfusion resulting in occipital lobe infarction in the visual cortex. It usually manifests as bilateral visual loss, ranging from bilateral homonymous hemianopia to complete visual loss. It is thought to be the rarest cause of POVL in spine patients. The prognosis is better than the other causes of POVL, with most patients recovering vision to some degree.
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