Related Experiment Video
Updated: Jul 16, 2026
12:23
Dynamic Visual Tests to Identify and Quantify Visual Damage and Repair Following Demyelination in Optic Neuritis Patients
Published on: April 14, 2014
Congruency in homonymous hemianopia.
Sachin Kedar1, Xiaojun Zhang, Michael J Lynn
1Department of Ophthalmology, Emory University, Atlanta, Georgia 30322, USA.
American Journal of Ophthalmology
|March 17, 2007
Summary
Congruent homonymous hemianopia (HH) is often associated with occipital lobe lesions, but can occur with other brain lesion locations, particularly stroke-related ones. Caution is advised when using congruency to localize HH brain lesions.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Homonymous hemianopia (HH) is a visual field defect resulting from damage to the postchiasmal visual pathways.
- The congruency of the visual field defect has been traditionally used as a clinical sign to help localize the site of brain lesions causing HH.
Purpose of the Study:
- To evaluate the diagnostic value of visual field congruency in localizing brain lesions in patients presenting with homonymous hemianopia (HH).
Main Methods:
- A retrospective observational study reviewed 548 cases of incomplete HH over 15 years.
- Patients were categorized into congruent HH and incongruent HH groups based on visual field testing and neuroimaging.
- Demographic, clinical, and radiological characteristics were compared between the groups.
Main Results:
- Of 548 incomplete HH cases, 373 were congruent and 175 were incongruent.
- Stroke was the primary cause for both congruent (75%) and incongruent (55.8%) HH.
- While occipital lobe lesions were more frequently congruent (47.9%), significant proportions of optic radiation (50.6%) and optic tract (16.3%) lesions also presented as congruent HH.
Conclusions:
- Congruent HH is characteristic of occipital lobe lesions but is also frequently observed with lesions in the optic radiations and optic tracts, especially those caused by stroke.
- The clinical rule of using congruency to localize brain lesions in HH should be applied cautiously, as it is not consistently reliable for all lesion locations, particularly the optic tract.
More Related Videos
Related Concept Videos
01:12Visual Agnosia
Visual agnosia is a condition characterized by the inability to recognize visually presented objects despite having normal vision. For instance, a person with visual agnosia can describe the shape and color of an object but cannot identify or name it. This impairment does not affect their visual field, acuity, color vision, brightness discrimination, language, or memory. An example of this condition in a social setting is someone at a dinner party asking for "that silver thing with a round end"...
01:24Prosopagnosia
Prosopagnosia, also known as face blindness, is the inability to recognize faces. In severe cases, individuals with prosopagnosia may not recognize close family members, including parents and spouses, by their faces. For instance, someone with prosopagnosia might walk past their child in a crowd, only realizing their mistake upon noticing their child's distinctive backpack or favorite jacket. Prosopagnosia specifically impairs facial recognition, while the recognition of other objects or...
01:05Cerebral Hemispheres
The human brain, a complex organ, is functionally divided into two cerebral hemispheres—left and right. These hemispheres are interconnected by a structure of paramount importance, the corpus callosum. This substantial bundle of neural fibers is not just a bridge between the hemispheres but a crucial element for the brain's comprehensive functioning. It enables efficient communication between the two hemispheres, allowing each side of the brain to control and receive sensory and motor...
01:28Lateralization
Brain lateralization refers to the division of mental processes and functions between the two hemispheres of the brain, a phenomenon that optimizes neural efficiency and underpins complex abilities in humans. This specialization allows each hemisphere to perform tasks where it has a comparative advantage, facilitating more refined cognitive capabilities across different domains.
01:25Glaucoma: Overview
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...