What is altitudinal visual field defect?
Altitudinal visual field defect (VFD), which involves the loss of visual sensation in the horizontal half of the visual field, is caused mainly by anterior ischemic optic neuropathy (AION),1,2,3 or rarely by compressive neuropathy due to a tumor or aneurysm.
What is Binasal hemianopia?
Binasal hemianopsia is the medical description of a type of partial blindness where vision is missing in the inner half of both the right and left visual field. It is associated with certain lesions of the eye and of the central nervous system, such as congenital hydrocephalus.
What visual field defects indicate glaucoma?
Relatively specific glaucomatous visual field defects (see Figure 3 for examples) include:
- a nasal step defect obeying the horizontal meridian.
- a temporal wedge defect.
- the classic arcuate defect, which is a comma-shaped extension of the blind spot.
- a paracentral defect 10–20° from the blind spot.
What is an arcuate visual field defect?
Arcuate (Arc): Significant visual field loss in the nerve fiber bundle region. Extends across contiguous abnormal points from the blind spot to at least 1 point outside 15° adjacent to the nasal meridian.
What are the two types of visual fields?
The monocular visual field consists of central vision, which includes the inner 30 degrees of vision and central fixation, and the peripheral visual field, which extends 100 degrees laterally, 60 degrees medially, 60 degrees upward, and 75 degrees downward (Figure 116.1) A vertical line bisects central fixation and …
What can causes a Binasal visual field defect?
Organic causes of this unusual field defect include brain space occupying lesions, keratoconus, bilateral internal carotid aneurysms, neurosyphilis, optic neuropathy, optic disc drusen and optic nerve pits, retinitis pigmentosa sine pigmento, as well as pneumosinus dilatans of the sphenoid sinuses.
What causes a visual field defect?
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.