Optic Nerve Lesions and Visual Field Defects

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Questions and Answers

What type of visual field defect is seen in a lesion to the center of the chiasm?

  • Central VFD
  • Bitemporal hemianopsia (correct)
  • Homonymous hemianopsia
  • Junctional scotoma

Which of the following lesions causes a central VFD in one eye and a partial temporal VFD in the opposite eye?

  • Lesion to the proximal fibers of an ON and the nasal fibers of the opposite eye (correct)
  • ON lesion
  • Lesion to the optic radiations
  • Lesion to the optic tract

What is the term for a visual field defect that affects one side of the visual field in both eyes?

  • Central VFD
  • Homonymous hemianopsia (correct)
  • Bitemporal hemianopsia
  • Junctional scotoma

Which lobe is associated with an inferior quadrantanopsia?

<p>Parietal lobe (D)</p> Signup and view all the answers

What type of lesion causes a homonymous hemianopsia?

<p>Lesion to the optic radiations (B)</p> Signup and view all the answers

What is the term for a visual field defect that affects the upper quadrant of the visual field?

<p>Superior quadrantanopsia (D)</p> Signup and view all the answers

Which condition is associated with a central VFD?

<p>Optic neuritis (D)</p> Signup and view all the answers

What type of lesion causes a bitemporal hemianopsia?

<p>Chiasm lesion (B)</p> Signup and view all the answers

Which condition is associated with an altitudinal VFD?

<p>Anterior ischemic optic neuropathy (AION) (B)</p> Signup and view all the answers

What type of lesion causes a junctional scotoma?

<p>Lesion to the proximal fibers of an ON and the nasal fibers of the opposite eye (C)</p> Signup and view all the answers

What is the normal range of a single eye's visual field in degrees?

<p>130-145 degrees (D)</p> Signup and view all the answers

Where is the physiological blind spot located in relation to the eye being evaluated?

<p>15 degrees temporal and 5 degrees inferior from central fixation (B)</p> Signup and view all the answers

What is the primary function of the central visual field?

<p>Color vision and details (B)</p> Signup and view all the answers

What is the range of the temporal visual field in degrees?

<p>100-110 degrees (C)</p> Signup and view all the answers

What is the term for the loss or defect of the visual field that may be the only sign of a lesion in the visual pathway?

<p>Visual field defect (A)</p> Signup and view all the answers

What is the primary function of the peripheral visual field?

<p>Detection of motion signals (D)</p> Signup and view all the answers

What is the range of the nasal visual field in degrees?

<p>60 degrees (A)</p> Signup and view all the answers

What is the term for the type of visual field defect that occurs when there is a lesion in the optic nerve?

<p>Central scotoma (D)</p> Signup and view all the answers

What is the range of the superior visual field in degrees?

<p>50-60 degrees (D)</p> Signup and view all the answers

What is the term for the type of visual field defect that occurs when there is a lesion in the chiasm?

<p>Bitemporal hemianopsia (C)</p> Signup and view all the answers

What type of visual field defect is associated with optic nerve lesions?

<p>Monocular ipsilateral defect (D)</p> Signup and view all the answers

What is the common cause of a right complete homonymous hemianopsia?

<p>A stroke in the left side of the brain (D)</p> Signup and view all the answers

What type of visual field defect is often associated with pituitary gland tumors?

<p>Bitemporal hemianopsia (D)</p> Signup and view all the answers

What is the characteristic of a pre-chiasmal altitudinal defect?

<p>It respects the horizontal meridian (A)</p> Signup and view all the answers

What type of lesion would cause a visual field defect in the left side of both eyes?

<p>Post-chiasmal lesion in the left side of the brain (C)</p> Signup and view all the answers

What type of visual field defect is characterized by a loss of half of the visual field in one eye?

<p>Monocular hemianopsia (C)</p> Signup and view all the answers

What is the term for a visual field defect that affects the same half of the visual field in both eyes?

<p>Homonymous hemianopsia (B)</p> Signup and view all the answers

What type of lesion is typically associated with a bitemporal hemianopsia?

<p>Chiasm lesion (B)</p> Signup and view all the answers

What is the term for a circular area of depressed vision surrounding the point of fixation?

<p>Annular scotoma (C)</p> Signup and view all the answers

What is the term for a visual field defect that affects the peripheral vision?

<p>Peripheral scotoma (D)</p> Signup and view all the answers

What is the primary function of the peripheral visual field?

<p>Detection of motion signals (C)</p> Signup and view all the answers

What is the location of the physiological blind spot in relation to the eye being evaluated?

<p>15 degrees temporal and 5 degrees inferior from central fixation (D)</p> Signup and view all the answers

What is the range of the temporal visual field in degrees?

<p>100-110 degrees (B)</p> Signup and view all the answers

What is the primary function of the central visual field?

<p>Recognition of detailed vision and color vision (A)</p> Signup and view all the answers

What is the range of the inferior visual field in degrees?

<p>60-80 degrees (D)</p> Signup and view all the answers

What type of visual field defect is often associated with lesions to the proximal fibers of an optic nerve and the nasal fibers of the opposite eye?

<p>Junctional scotoma (D)</p> Signup and view all the answers

What type of lesion causes a homonymous hemianopsia?

<p>Lesion to the optic tract (B)</p> Signup and view all the answers

What type of visual field defect is seen in patients with retinitis pigmentosa?

<p>Peripheral VFD (C)</p> Signup and view all the answers

What type of lesion causes an inferior quadrantanopsia?

<p>Lesion to the parietal lobe (C)</p> Signup and view all the answers

What type of visual field defect is seen in patients with anterior ischemic optic neuropathy (AION)?

<p>Altitudinal VFD (C)</p> Signup and view all the answers

What type of visual field defect is seen in patients with strokes (CVA) or traumatic brain injury (TBI)?

<p>Any of the above (D)</p> Signup and view all the answers

What is the purpose of confrontation visual fields (CVF) and finger counting fields (FCF)?

<p>To evaluate the extent of visual field defects (B)</p> Signup and view all the answers

What is the term for a visual field defect that affects the same half of the visual field in both eyes?

<p>Homonymous hemianopia (D)</p> Signup and view all the answers

What is the characteristic of a post-chiasmal altitudinal defect?

<p>Respects the vertical meridian (B)</p> Signup and view all the answers

What is the term for a circular area of depressed vision surrounding the point of fixation?

<p>Annular scotoma (B)</p> Signup and view all the answers

What is the term for a visual field defect that affects the upper quadrant of the visual field?

<p>Superior altitudinal defect (D)</p> Signup and view all the answers

What is the characteristic of a congruous visual field defect?

<p>The same size and shape in both eyes (B)</p> Signup and view all the answers

What type of visual field defect is often associated with glaucoma?

<p>Depression or constriction (A)</p> Signup and view all the answers

Flashcards

Visual Field Defect (VFD)

A loss of vision in a specific area of the visual field, caused by damage to the visual pathway.

Central VFD

Loss of vision in the central 30 degrees of vision, often affecting the central part of the visual field.

Peripheral VFD

Loss of vision in the outer parts of the visual field.

Hemianopia

Loss of vision in half of the visual field.

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Quadrantanopia

Loss of vision in a quarter of the visual field.

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Altitudinal VFD

Loss of vision above or below a horizontal line in vision

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Pre-chiasmal lesion

Damage to the optic nerve or pathways before the optic chiasm.

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Chiasmal lesion

Damage to the optic chiasm.

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Post-chiasmal lesion

Damage to the optic pathways after the optic chiasm.

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Scotoma

A small area of impaired vision surrounded by normal vision.

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Congruous VFD

Symmetric loss of vision in both eyes.

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Incongruous VFD

Asymmetric loss of vision in both eyes.

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Study Notes

Visual Field Defects

  • A lesion in the visual pathway can cause visual field defects (VFDs) which can be classified into different types based on their location and shape.

Types of Visual Field Defects

  • Central VFD: a defect in the central 30 degrees of vision, often seen in optic neuritis, macular hole, cone dystrophy, BRAO, and BRVO.
  • Peripheral VFD: a defect in the peripheral vision, often seen in retinitis pigmentosa, BRVO, BRAO, hysterical amblyopia, and Streff Syndrome.
  • Hemianopia: a defect in half of the visual field, often seen in strokes (CVA), traumatic brain injury (TBI), and intracranial mass.
  • Quadrantanopia: a defect in a quarter of the visual field, often seen in strokes (CVA), traumatic brain injury (TBI), and intracranial mass.
  • Altitudinal VFD: a defect above or below the horizontal meridian, often seen in anterior ischemic optic neuropathy (AION), compressive neuropathy, BRAO, BRVO, papilledema, and disc edema.

Visual Pathway Lesions

  • Lesions in the visual pathway can cause different types of VFDs:
    • Pre-chiasmal lesions: monocular ipsilateral defect (e.g., macular hole, retinal detachments, glaucomatous changes, optic atrophy, or optic neuropathy).
    • Chiasmal lesions: bitemporal hemianopsia (e.g., tumor compressing pituitary gland or aneurysm of the anterior communicating artery).
    • Post-chiasmal lesions: homonymous hemianopsia (e.g., stroke, traumatic brain injury, or intracranial mass).

Visual Field Evaluation

  • Confrontation Visual Fields (CVF) and Finger Counting Fields (FCF) are methods used to evaluate the visual field.
  • Automated perimetry and tangent screens are more detailed methods used to evaluate the visual field.
  • Visual field defects can be categorized as congruous (symmetric) or incongruous (asymmetric).

Terminology

  • Depression/Constriction: a general reduction in overall sensitivity of the visual field.
  • Scotoma: an area of depressed vision surrounded by an area of less depressed or normal vision.
  • Shallow or Relative Scotoma: an area of the retina that is not sensitive to relatively dim stimuli but is sensitive to brighter/lighter stimuli.
  • Deep or Absolute Scotoma: no response to a stimulus regardless of brightness or size.

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