Fall 2014: Lecture 4: Neuro Visual Fields

Question 1

1. The Cerebral Cortex receives Encoded images of what VF’s of which eyes?

Answer 1

1. of the CONTRALATERAL VFs of BOTH EYES!

Question 2

LGN

1. Dual Blood supply from what 2 Arteries?
   a. HILUM is supplied by what artery?
   b. Medial and Lateral Horns Supplied by what Artery?

Answer 2

1. Anterior and Posterior Choroidal Arteries
   a. Posterior Choroidal Artery
   b. Anterior Choroidal Artery

Question 3

Optic Radiations: Leave the LGN to the Visual Cortex

1. Which Optic Radiations are called the MEYER’s LOOP?
   a. This is carrying info form which part of the VF and which part of the RETINA?
2. Which are called just the Optic Radiations?
   a. this is carry info from what part of the VF and what part of the RETINA?

Answer 3

1. The horizontal ones that go to the TEMPORAL LOBE!
   a. More SUP VF and Inf. Retina
2. The Superior ones that go to the PARIETAL LOBE
   a. (More of an INFERIOR VF and SUPERIOR RETINA)

Question 4

Occipital Lobe

1. What CENTRAL DEGREES occupies a Disproportionate Area of the VISUAL CORTEX (50-60%)?
   a. Where is the Macular Representation located?
   b. The area that Corresponds to the TEMPORAL 30 DEGREES of the VF is LOCATED more where?

Answer 4

1. The CENTRAL 10 DEGREES!
   a. At the TIP of the OCCIPITAL LOBES!!!

b. More ANTERIORLY in the VISUAL CORTEX!!

Question 5

HVF 30-2 vs. Goldmann Full Field

1. How Much VF do we have Superiorly?
2. Inferiorly?
3. Temporally?
4. Nasally?

Answer 5

1. About 70 degrees
2. 60-70 Degrees
3. About 100 Degrees
4. About 60 degrees

Question 6

Evaluating a VF

1. Viewed from Doctor/Pt Perspective?
2. Blind Spot Temporal CORRESPONDS to what?
3. Want to look at these VFs how?

Answer 6

1. PT’s PERSPECTIVE!!
2. To the NASAL LOCATION of the OPTIC NERVE!
3. SIDE by SIDE!!

Question 7

Optic Nerve Defects

1. What do they Follow?
2. What Meridian do they RESPECT?
3. They Originate from what?
4. 3 Types of RNFL Defects?

Answer 7

1. the Distribution of the RNFL
2. HORIZONTAL MERIDIAN
3. From the BLIND SPOT; NOT from FIXATION!!! (However, it doesn’t always go all the way back to the Blind Spot itself)
4. a. Papillomacular Bundle (Dz that affects the Temporal Part of the Nerve will have an AFFECT here)
   b. Arcuate Nerve Fiber Bundles (Dz that affects Sup/Inf Nerve)
   c. Nasal Nerve Fiber Bundles (Nasal part of the nerve)

Question 8

Optic Nerve Defects (2)

1. Papillomacular Bundle
   a. Retinal Nerve Fibers from the MACULA Enter what side of the OPTIC NERVE?
   b. 3 Types of Defects that you will see? (Slide 15)

Answer 8

1. a. The TEMPORAL SIDE

b. CENTRAL; Centrocecal (Goes all the way to the Blind Spot), and Paracentral

Question 9

Optic Nerve Defects (3)

1. Arcuate Nerve Fiber Bundles
   a. Retinal Nerve Fibers from the TEMPORAL RETINA enter where on the OPTIC NERVE?

b. 3 Types of Defects seen?

Answer 9

1. a. Enter the SUP and INF Poles of the OPTIC NERVE

b. Nasal Step; Arcuate Scotoma; Seidel Scotoma (Almost Comma Shaped)

Question 10

Optic Nerve Defects (4)

1. Nasal Nerve Fiber Bundle
   a. Fibers from the Retina NASAL to the Optic Nerve enter what side of the OPTIC NERVE?

b. Defect type?

Answer 10

1. a. the NASAL SIDE!!

b. Temporal Wedge Scotoma, Arising from the Blind Spot

Question 11

1. A VF Defect that goes back to the point of FIXATION is referred to as?

Answer 11

1. As a RETRO-CHIASMATIC

Question 12

Optic Nerve Defects (5)

1. Optic Nerve Defects should ALWAYS CORRESPOND to what?

Answer 12

1. To the APPEARANCE of the OPTIC NERVE!!

Question 13

Characteristics of Lesions at the CHIASM!!!

1. Temporal or Bitemporal Defects?
   a. Due to involvement of what from each eye?
2. When will it look more ASYMMETRIC?
3. A CENTRAL DEFECT in 1 EYE w/a TEMPORAL DEFECT in the OTHER EYE indicates a LESION where?
   a. What is this called?
4. Almost ALWAYS caused by what?

Answer 13

1. BITEMPORAL
   a. of DECUSSATING NASAL FIBERS from each eye.
2. If the LESION extends more to one SIDE!!
3. at the JUNCTION of the OPTIC NERVE and CHIASM!
   a. a JUNCTIONAL SCOTOMA!
4. by a Pituitary TUMOR!!

Question 14

Nasal Hemianopia

1. How common is a True Nasal Hemianopia?
   a. 3 Etiologies…

Answer 14

1. VERY RARE!!
   a. Aneurysm of the ICA!
   b. Neoplasm Compressing the LATERAL Aspect of the OPTIC NERVE
   c. Non-Organic? (i.e….MALINGERING!!) (Probably the most common cause)

Question 15

Characteristics of Lesions POSTERIOR to the Optic Chiasm.

1. Are they Homonymous?
2. Complete or Incomplete?
3. What meridian or midline do they respect?
4. Where MIGHT they originate from?
5. Where will they NOT originate from?
6. Where is the LESION located in relation to the field defect?

Answer 15

1. YES (Bi-left or bi-right)
2. Either
3. VERTICAL
4. May originate from FIXATION
5. from the blindspot
6. It will be CONTRALATERAL to the Field DEFECT!
   * So, Rt. Side Visual Field DEFECTS are from LESIONS on the LEFT side of the BRAIN!!!

Question 16

1. Quadrantanopia (Quadrantanopsia): Define

2. Hemianopia (Hemianopsia): Define

Answer 16

1. Loss of vision in either the Upper or Lower Aspect of one hemifield
2. Loss of vision in 1/2 of the visual field

Question 17

Congruity

1. What is Congruity?
2. It’s determined by what?
3. When does Congruity increase: more anterior or posterior of a lesion?

Answer 17

1. Amt of Similarity b/w the field defects in each eye (Location, shape, size, depth, margins)
2. by how closely adjacent nerve fibers from corresponding retinal points are to one another along the visual pathway.
3. MORE POSTERIOR of a lesion… (Cookie Cutter defects = more similar)

Question 18

Describing Congruity

1. Congruous…where?
2. Incongruous…where?
3. Complete….where?

Answer 18

1. Occipital Lobe
2. Optic Tract or Optic Radiations
3. Can’t tell location…only that it’s somewhere POSTCHIASMAL!!

Question 19

LGN Defects

1. Sector Defect Due to what? (Slide 33)
2. Sector-SPARING Defect due to what? (Slide 33)

Answer 19

1. of the Posterior Choroidal Artery

2. Anterior Choroidal Artery

Question 20

Superior-Inferior Separation

1. After the LGN what RETINAL FIBERS course into the TEMPORAL Lobe forming Meyer’s LOOP?
2. TEMPORAL LOBE LESIONS Affect what FIBERS FIRST?

Answer 20

1. The Inferior Retinal Fibers

2. The INFERIOR FIBERS –> SUPERIOR VF DEFECT!! (“Pie in the SKY)

Question 21

Sup-Inf Separation (2)

1. Superior Retinal Fibers Course where after the LGN?
2. PARIETAL LOBE LESION affects what Fibers first?

Answer 21

1. in the Optic Radiations of the PARIETAL LOBE

2. SUPERIOR FIBERS FIRST –> INF VF DEFECT (“PIE IN THE FLOOR”)

Question 22

PITS

1. PI =?
2. TS
3. If the VF DEFECT is HIGHLY CONGRUOUS, it’s MORE LIKELY due to what KIND OF LESION?

Answer 22

1. Parietal = Inferior VF Defect
2. Temporal = Superior VF Defect
3. More likely due to an OCCIPITAL LOBE LESION, regardless of whether it’s Predominantly Superior or Inferior.

Question 23

Macular Sparing

1. What is it?
2. MACULAR SPARING is due to what reason?

Answer 23

1. A HEMIANOPIA w/SPARING of the CENTRAL area of Vision

2. the DUAL BLOOD SUPPLY to the MACULAR AREA of the VISUAL CORTEX!!

Question 24

Macular Sparing

1. Macular area of the Visual Cortex at the Tip of the occipital lobe is Supplied by TERMINAL BRANCHES of what ARTERIES?
2. Visual Cortex corresponding to the MIDPERIPHERAL and PERIPHERAL VF is supplied only by what artery?
3. When there’s an Obstruction in the PCA, the Macular area of the Visual Cortex may be Spared because of BLOOD SUPPLY from what?

Answer 24

1. Posterior and Middle Cerebral Arteries
2. the PCA ONLY!
3. MCA.

Question 25

Macula Only 1. What is it? 2. Usual cause?

Answer 25

1. Central Homonymous Hemianopia due to a LESION at the TIP of the OCCIPITAL LOBE! 2. NEOPLASM!!

Question 26

Enlarged Blindspot 1. Term reserved for a Blindspot that's enlarged how? a. MOST Commonly associated with what? 2. Extension of the Blindspot: Define.

Answer 26

1. In ALL DIRECTIONS a. with PAPILLEDEMA 2. refers to a blindspot that's EXTENDED in one direction