Visual Fields Explained

Question 1

Upper nasal visual quadrant

Answer 1

Upper nasal visual quadrant projects to the lower temporal retinal quadrant

Question 2

Lower nasal visual quadrant

Answer 2

Lower nasal visual quadrant projects to the upper temporal retinal quadrant

Question 3

Upper temporal visual quadrant

Answer 3

Upper temporal visual quadrant projects to the lower nasal retinal quadrant

Question 4

Lower temporal visual quadrant

Answer 4

Lower temporal visual quadrant projects to the upper nasal retinal quadrant

Question 5

Retinogeniculostriate System

Answer 5

Fibers from the temporal hemiretina do not cross in the optic chiasma; fibers from the nasal hemiretina cross in the optic chiasma.

Rule of L’s

Information from the Lower hemiretina projects to the Lateral part of the
Lateral geniculate body, the Loop of Meyer, and the Lingual gyrus.

Retinotopic organization is maintained throughout the
system from the retina to visual cortex.

Question 6

A blindness of one-half of the visual field

Answer 6

Heminopia: A blindness (-anopia or -anopsia) of one-half of the visual field. In clinical terms, a nasal hemianopia of the left eye indicates a lesion of the temporal hemiretina of the left eye, or somewhere along the length of the retinogeniculocalcarine pathway, which conveys that specific information.

Question 7

A blindness of a quadrant of the visual field.

Answer 7

Quadrantanopia: A blindness of a quadrant of the visual field.

The most common quadrantanopia involves the upper nasal quadrant of one eye + the upper temporal quadrant of the other eye.

This pattern is called a superior quadrantanopia, a homonymous condition.

Question 8

heteronymous blindness in the nasal fields of each eye.

Answer 8

Binasal hemianopia:

due to a bilateral lesion of the lateral aspect of the optic chiasma that results in a heteronymous blindness in the nasal fields of each eye. It may also be only unilateral, since

Question 9

a nasal hemianopia of one eye

Answer 9

A unilateral lesion of the lateral aspect of the optic chiasma results in a nasal hemianopia of the ipsilateral eye. Below is an example of a lesion of the temporal retina of the left eye that would result in a (right) nasal hemianopia of the left eye.

Question 10

blindness in the temporal fields of both eyes

Answer 10

Bitemporal hemianopia may be due to a midline lesion of the medial portion of the optic chiasma. This heteronymous deficit is usually caused by pituitary tumors.

Question 11

Unilateral lesions of the lateral geniculate body

Answer 11

Contralateral homonymous hemianopia.

Unilateral lesions of the lateral geniculate body, complete optic radiations or visual cortex result in a contralateral homonymous hemianopsia. Below is an example of a left homonymous hemianopia, which would indicate a lesion on right visual pathway, i.e., optic tract, lateral geniculate body or complete optic radiations.

Question 12

Unilateral lesions of the complete optic radiations

Answer 12

Contralateral homonymous hemianopia.

Unilateral lesions of the lateral geniculate body, complete optic radiations or visual cortex result in a contralateral homonymous hemianopsia. Below is an example of a left homonymous hemianopia, which would indicate a lesion on right visual pathway, i.e., optic tract, lateral geniculate body or complete optic radiations.

Question 13

Unilateral lesions of the visual cortex

Answer 13

Contralateral homonymous hemianopia.

Unilateral lesions of the lateral geniculate body, complete optic radiations or visual cortex result in a contralateral homonymous hemianopsia. Below is an example of a left homonymous hemianopia, which would indicate a lesion on right visual pathway, i.e., optic tract, lateral geniculate body or complete optic radiations.

Question 14

Incongruent contralateral homonymous hemianopia with macular sparing

Answer 14

Incongruent contralateral homonymous hemianopia with macular sparing is usually indicative of a unilateral lesion of the visual cortex.

may be due to obstruction of the posterior cerebral artery.

Lesions of the visual cortex are usually incongruous (asymmetrical)

lesions of the LGB or optic radiations are congruous in their visual field deficits.

Question 15

Lesions of the pathway from the lateral geniculate body and the primary visual

Answer 15

Lesions of the pathway from the lateral geniculate body and the primary visual, inclusive, may leave the visual reflexes intact

Question 16

Infarction of the left occipital lobe and posterior corpus callosum secondary to occlusion of the posterior cerebral artery

Answer 16

Associative visual agnosia

. Infarction of the left occipital lobe and posterior corpus callosum secondary to occlusion of the posterior cerebral artery may disconnect the language area from the visual association cortex.

Question 17

the patient cannot name or describe an object in the visual field but correctly recognized and demonstrated its use.

Answer 17

Associative visual agnosia. Infarction of the left occipital lobe and posterior corpus callosum secondary to occlusion of the posterior cerebral artery may disconnect the language area from the visual association cortex.

Although the patient cannot name or describe an object in the visual field, he can recognize and demonstrate its use. Visual perception is intact. Most of these patients are also alexic (unable to read), and writing ability may be affected (agraphia).