quadrantanopia


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quadrantanopia

 [kwod″ran-tah-no´pe-ah]
defective vision or blindness in one fourth of the visual field.

qua·drant·an·o·pi·a

(kwah'drant-an-ō'pē-ă),
Loss of vision in a quarter section of the visual field of one or both eyes; if bilateral, it may be homonymous or heteronymous, binasal or bitemporal, or crossed, for example, involving the upper quadrant in one eye and the lower quadrant in the other.

quadrantanopia 

Visual field loss in a quarter of the visual field of the eye. The defect is usually bilateral, as it is caused by a lesion past the optic chiasma. It may be homonymous (binasal, bitemporal, upper or lower), crossed (one upper and the other lower), congruous (equal size of the defects), or incongruous (unequal size of the defects) (Fig. Q1). Syn. quadrantanopsia; quadrantic anopsia; quadrantic hemianopia. See hemianopia.
Fig. Q1 Complete, right, superior homonymous quadrantanopia due to a lesion of the optic radiations in the left temporal lobeenlarge picture
Fig. Q1 Complete, right, superior homonymous quadrantanopia due to a lesion of the optic radiations in the left temporal lobe
References in periodicals archive ?
(16) Patients with hemianopia and quadrantanopia (especially inferior quadrantic defects) were noted to have difficulty with lane position/lane change, steering steadiness, and gap judgment compared to normal controls.
Visual defects vary from sector shaped defects, quadrantanopias to total hemianopia.
Age (years) 12 (i) at seizure onset/ 0,2/6; 9/still present (ii) at last seizure Birth and delivery Hypoglycemia (neonatal convulsions) Visual field Bilateral inferior quadrantanopia Interictal EEG Left abnormalities temporoparietooccipital spikes and slow waves with contralateral spread Ictal EEG NA Seizure semiology Unresponsiveness, head deviation to the left, hypotonia, and falls Treatment VPA + ESM + TPM G.
Caption: Figure 2A Visual representation of a left hemianopic defect; (13) 2B Perimetric data showing a left hemianopia; 2C Perimetric data showing a left superior quadrantanopia
This study was part of a larger study investigating the driving performance and safety of individuals with homonymous hemianopia and quadrantanopia [2, 3,12, 13].
Exclusion criteria were Parkinson's disease, multiple sclerosis, Alzheimer's disease, hemiparesis, ocular or neurological conditions resulting in visual field defects (other than hemianopia or quadrantanopia), and lateral spatial neglect as defined by the Stars test [14].
For the participants with quadrantanopia, half had left-sided loss and half right-sided loss, with two with superior loss and two with inferior field loss.
The findings of this study suggest that clinical information on neuroimaging, as is available in standard clinical practice in managing patients with hemianopia and quadrantanopia, is not sufficient for neuroophthalmologists to predict driving safety.
Unilateral infarcts cause contralateral visual field abnormalities such as inferior and/or superior quadrantanopia. Contralateral hemianopia results when both regions are involved.
Lesions which occur after the LGN produce more congruent quadrantanopias (optic radiations), respecting the midlines, or hemianopic defects if the whole optic radiation is affected.
A centrocaecal scotoma in one eye accompanied by a superior temporal quadrantanopia in the other eye, termed a 'junctional' scotoma, is suggestive of a prechiasmal lesion close to where the optic nerve meets the chiasm (Figure 3 C).
(c) A contralateral, homonymous, inferior quadrantanopia arises from damage to the inferior fibres of the optic radiations.