Clinical Examination of Vision

Question 1

Right visual field is seen in the ____ side of brain

Answer 1

Right visual field is seen in the LEFT side of brain

in occipital cortex

Question 2

The inferior retina sees _____ portion of the visual field

Answer 2

The inferior retina sees UPPER portion of the visual field

Question 3

The superior retina sees _____ portion of the visual field

Answer 3

The superior retina sees LOWER portion of the visual field

Question 4

The temporal retina sees _____ portion of the visual field

Answer 4

The temporal retina sees NASAL portion of the visual field

Question 5

The nasal retina sees _____ portion of the visual field

Answer 5

The nasal retina sees TEMPORAL portion of the visual field

Question 6

Which pt of the retina allows for visual acuity?

Answer 6

Center of retina

Question 7

Small objects are only seen closer or farther to center of visual field?

Answer 7

CLOSER

Question 8

What is the implication of the optic nerve’s nasal location?

Answer 8

Creates a blind spot over temporal vision

Question 9

There is an absence of ___________ where the optic nerve leaves the eye.

Answer 9

There is an absence of RODS/CONES where the optic nerve leaves the eye (area of optic nerve head).

Question 10

The optic nerve head (cup) receives retinal ganglion cell axons as they arch from above/below the __________________

Answer 10

The optic nerve head (cup) receives retinal ganglion cell axons as they arch from above/below the HORIZONTAL MERIDIAN OF THE RETINA

Question 11

Where do most visual field defects begin and why?

Answer 11

Most begin in CENTER of vision and move out towards periphery.

(bc 90% of fibers in optic n. carry info from central 30 degrees of the visual field and lose their arcuate distribution as they travel through the orbit towards the optic chiasm)

Question 12

Relative afferent pupillary defect can occur with minimal damage to the _______

Answer 12

Relative afferent pupillary defect can occur with minimal damage to the OPTIC N.
(Rarely w/ retinal damage, would need “ancient and devastating” level of damage)

Question 13

Relative afferent pupillary defect, explain positive test

Answer 13

If optic n. is damaged, when light is shined in that eye, both pupils will DILATE.

Question 14

Which retinal axons cross at chiasm? What is the implication of this?

Answer 14

Axons from nasal retina.

Chiasmal visual field defects are typically bitemporal.

Question 15

Each optic tract carries info from contralateral hemifield of both eyes to the lateral geniculate bodies. What does this imply for optic tract disease?

Answer 15

Optic tract disease causes hemianopic defects affecting the same (homonymous) contralateral visual field of each eye.

Question 16

After leaving lateral geniculate body, visual radiations carry info from the lower retina (upper visual field) to where?

Answer 16

These fibers loop down into temporal lobe (Meyer’s loop).

Question 17

After leaving lateral geniculate body, visual radiations carry info from the upper retina (lower visual field) to where?

Answer 17

These fibers pass up directly through the parietal lobe.

Question 18

A temporal lobe lesion picking off Meyer’s loop will cause what type of defect?

Answer 18

An upper field defect in both eyes.

Question 19

Most of the occipital lobe is concerned with the _____ field of vision and information from corresponding points from the visual fields of each eye is processed by neurons which are _______.

Answer 19

Most of the occipital lobe is concerned with CENTRAL field of vision and information from corresponding points from the visual fields of each eye is processed by neurons which are CLOSE TO EACHOTHER.

Question 20

Occipital lobe disease causes which type of defects?

Answer 20

Occipital lobe disease causes central, homonymous visual field defects, which are identical (congruous).

Question 21

Visual field testing methods

Answer 21

• Confrontation
• Grid
• Tangent screen
• Manual perimeter
• Automated visual field
• Multifocal visual evoked potential

Question 22

Multifocal visual evoked potential

Answer 22

Visual field test where brain waves are recorded from occipital lobe in response to checks flashing in visual field. Problem with visual field will show noisy signal indicating poor transmission.

Question 23

Which part of occipital lobe does peripheral info come into?

Answer 23

Anterior tip of occipital cortex

Question 24

Which part of occipital lobe does central info come into?

Answer 24

Posterior portion of occipital cortex

Question 25

If discreet area is missing in one eye and no afferent pupillary defect is present, suspect which type of damage?

Answer 25

Retinal damage

Question 26

If a visual field deficit is superior and temporal, describe the retinal lesion.

Answer 26

The retinal lesion should be nasal and inferior.

Question 27

You observe a visual field deficit that is inferior and respects the horizontal meridian (immediately after crossing horizontal meridian, can’t see). Describe the lesion.

Answer 27

Lesion must be superior, close to or at the OPTIC NERVE HEAD.
Lesion is preventing ganglion cell axons from entering the optic nerve.

Question 28

Optic Nerve Damage findings

Answer 28

• Loss of central vision in visual field
• Relative afferent pupillary defect
• Retina appears normal
• Imaging shows optic nerve inflammation

Question 29

bitemporal hemianopia

Answer 29

• bilateral temporal fields of vision missing
• info from temporal fields enters nasal retina but can’t cross in chiasm
• most common cause: pituitary adenoma putting pressure on chiasm

Question 30

Observe small paracentral defects in both eyes, not quite identical

Nasal field defect on R, temporal on L.

Describe lesion.

Answer 30

“Optic tracitis”
- inflammatory, can be caused by demyelinating plaques.

Lesion in R tract causing homonymous (L side) hemianopic scotomas.

Question 31

Visual loss to both R, upper fields.

Defects are similar (quadrantic shape) but not quite identical.

Describe lesion.

Answer 31

Damage to meyers loop in L temporal lobe
- Defects are similar but not quite identical, so fibers are affected after crossing but not yet where they come together (neurons in occipital lobe).

• Commonly causes: tumor, stroke.
• Lower fibers carry info from superior visual field.
• -> Causes homonymous “pie in the sky” defect (quadrantic shape).

Question 32

Entire field of vision is lost on R side in both eyes (complete hemianopia).

Answer 32

L-sided lesion is likely in the radiations, affecting all fibers coming from the R visual field in both eyes.
- Common cause: infarct in MCA.

(Unlikely to be an occipital lobe lesion, which spares the area near center, doesn’t split down middle.)

Question 33

Observe almost superimposable visual field defects. What does this suggest?

Answer 33

Neurons receiving info from visual fields on each side are situated near each other in OCCIPITAL lobe.

Lesion: possible arteriovenous (AVM) malformation in L occipital lobe causing R congruous, homonymous hemianopia.

Often lg area of occipital lobe that sees in center of vision is spared.

Question 34

Observe arching pattern of vision loss that respects the horizontal meridian. Where is the lesion?

Answer 34

At or near optic n. head.

• glaucoma
• ischemic optic neuropathy

Question 35

Observe blob shape visual defect on one eye.

Retina appears normal.

Where is lesion?

Answer 35

Lesion is behind eye, likely along optic n. (especially if relevant pupillary defect).

Question 36

junctional scotoma

Answer 36

Temporal field of vision loss on one side, optic n. defects on other side.

Lesion where optic n. comes into chiasm as they cross.