The nasal retina receives visual information from the temporal field, and the temporal retina receives visual information from the nasal field.
Where is the temporal retina?
The right and left halves of each visual field are reversed in their projection onto the retina so that the temporal (lateral) retina looks at the nasal (medial) half of the visual field. The nasal retina looks at the temporal half of the visual field.
What is temporal field of vision?
Your field of vision can be measured in terms of degrees from the center. With a healthy and normal eye, you should be able to see approximately 95 degrees temporally (towards your ear) and approximately 60 degrees nasally (towards your nose) from the center.
What is nasal Hemiretina?
The fibers of the optic nerve that originate from ganglion cells in the nasal half of the retina (i.e., the nasal hemiretina) decussate in the optic chiasm to the opposite optic tract (Figure 15.1). Consequently, each optic tract has within it axons representing the contralateral half of the visual field.
What is Retinotopic representation?
Retinotopy (from Greek τόπος, place) is the mapping of visual input from the retina to neurons, particularly those neurons within the visual stream. In general, these complex maps are referred to as second-order representations of the visual field, as opposed to first-order (continuous) representations such as V1.
Is the macula nasal or temporal?
The avascular, dusky area two disk diameters due temporal to the disk is the macula. This is the area of greatest visual acuity.
What are the 3 fields of vision?
Using your Eyes Effectively
- Central vision.
- Peripheral or side vision.
What is horizontal field of vision?
Horizontal field of view –The central field of vision for most people covers an angle of between 50o and 60o. The visual impact of a development will vary according to the proportion in which a development impacts on the central field of vision.
What is a temporal defect?
Lesions of nasal retinal axons cause temporal field defects. If the nasal axons nearest the macula are spared, the resulting field defect shows sparing of the parafixational temporal hemifield (Figure 116.6).
What is monocular temporal hemianopia?
Monocular hemianopia is defined as the loss of the temporal or nasal visual field in one eye, which usually involves a specific lesion anterior to the optic chiasm (prechiasmal). Additionally, a lesion at the right lateral geniculate nucleus (postchiasmal) is expected to cause a binocular homonymous left hemianopia.
What is the optical lobe?
The occipital lobes sit at the back of the head and are responsible for visual perception, including colour, form and motion. Damage to the occipital lobe can include: Difficulty with locating objects in environment.
What is temporal retina?
The half of the retina that is nearest to the temple and from which nerve fibres are projected to the ipsilateral (same-side) cerebral hemisphere after passing through the optic chiasm. Compare nasal retina. From: temporal retina in A Dictionary of Psychology »
What is the difference between bitemporal and homonymous hemianopia?
Hemianopia usually affects corresponding halves of the visual fields of both eyes as it is usually due to damage to the optical nerve tracts behind the eyes that contain fibres from both eyes. In homonymous hemianopia there is loss of corresponding halves of the field of each eye. In bitemporal hemianopia both outer halves are lost.
What is the meaning of the word hemianopia?
/hemi·an·o·pia/ (-an-o´pe-ah) defective vision or blindness in half of the visual field of one or both eyes; loosely, scotoma in less than half of the visual field of one or both eyes.hemianop´ic. absolute hemianopia blindness to light, color, and form in half of the visual field.
What is contralateral hemianopsia?
A lesion of the right optic tract causes a complete loss of vision in the left hemifield: contralateral “homonymous ” hemianopsia . A lesion of the right optic radiation just after the LGN also causes a loss of vision in the left
