What causes visual field defects?
Causes of visual field defects are numerous and include glaucoma, vascular disease, tumours, retinal disease, hereditary disease, optic neuritis and other inflammatory processes, nutritional deficiencies, toxins, and drugs. Certain patterns of visual field loss help to establish a possible underlying cause.
What causes visual field neglect and what are some of its symptoms?
The most common causes of damage to the retina or optic nerve of the eye include glaucoma, coloboma, a toxoplasma infection, tumors, and age-related macular degeneration. If any of these conditions damage the center of the retina (the macula), the individual will most likely experience blurred vision.
What conditions may affect the visual field of the eye?
High blood pressure. Age-related macular degeneration (eye disorder that slowly destroys sharp, central vision) Multiple sclerosis (disorder that affects the CNS) Optic glioma (tumor of the optic nerve)
What causes sudden loss of peripheral vision in one eye?
Causes of peripheral vision loss can be as mild as an ocular migraine or a vitreous floater, to more serious, like a retinal detachment or a pituitary tumour. Other causes include glaucoma, stroke, retinitis pigmentosa, and brain aneurysms.
What causes gradual loss of vision?
Cataracts, refractive error, corneal blindness and early diabetic macular oedema are generally reversible. Optic atrophy, glaucoma, retinal degeneration and age-related macular degeneration usually cause permanent loss of vision. Most of these conditions are briefly discussed in this article.
What is Hemifield defect?
Disease. The retinal hemifield slide phenomenon occurs when heteronymous hemianopic defects result in visual fields that can not be easily fused and therefore disassociate from one another, causing a nonparetic diplopia.
Why is there macular sparing in PCA infarct?
The second theory holds that macular sparing arises because the occipital pole, where the macula is represented, remains perfused after occlusion of the posterior cerebral artery because it receives collateral flow from the middle cerebral artery.
What causes a nasal step visual field defect?
Nasal step defects are caused by optic nerve disorders that affect the long, arching axons that originate temporal to the macula, entering the disc superiorly or inferiorly. A nasal step may begin as a small depression above or below (and respecting) the horizontal meridian in the nasal visual field (see Figure 3–8A).
What causes homonymous visual field defects in retrochiasmal lesions?
Retrochiasmal lesions normally cause homonymous visual field defects; the only exception is the ‘temporal crescent’ or ‘half moon syndrome’, caused by a lesion in the anterior part of the contralateral parieto-occipital sulcus.
How are visual field defects used in diagnosis?
Diagnostic: Visual field defects indicate involvement of the visual pathways and the pattern of visual field defects help in localizing site of the lesion. Follow-up: Visual fields provide an excellent tool to monitor resolution and/or recurrence of disease processes affecting the visual pathways.
When does tilted disc syndrome cause visual field defects?
Visual field defects. When tilted disc is found bilaterally, the visual field defects may mimic optic chiasm disorders. 1 Axonal dysgenesis causes the visual field defects that occur with tilted disc syndrome. 2 These defects generally involve the temporal and superior visual field but may appear as an enlarged blind spot.
What causes unusual visual fields in brain injury?
Unusual Visual Fields from Bilateral Occipital Lobe Lesion Checkerboard Visual Field Defect: Bilateral quadranopsia caused by two separate lesions one above the calcarine fissure on one side of the brain and one below on the opposite side can produce a checkerboard pattern. This can occur from two simultaneous events or events separated in time.