Fall 2014: Lecture 4: Neuro Visual Fields Flashcards
1
Q
- The Cerebral Cortex receives Encoded images of what VF’s of which eyes?
A
- of the CONTRALATERAL VFs of BOTH EYES!
2
Q
LGN
- Dual Blood supply from what 2 Arteries?
a. HILUM is supplied by what artery?
b. Medial and Lateral Horns Supplied by what Artery?
A
- Anterior and Posterior Choroidal Arteries
a. Posterior Choroidal Artery
b. Anterior Choroidal Artery
3
Q
Optic Radiations: Leave the LGN to the Visual Cortex
- 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? - Which are called just the Optic Radiations?
a. this is carry info from what part of the VF and what part of the RETINA?
A
- The horizontal ones that go to the TEMPORAL LOBE!
a. More SUP VF and Inf. Retina - The Superior ones that go to the PARIETAL LOBE
a. (More of an INFERIOR VF and SUPERIOR RETINA)
4
Q
Occipital Lobe
- 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?
A
- The CENTRAL 10 DEGREES!
a. At the TIP of the OCCIPITAL LOBES!!!
b. More ANTERIORLY in the VISUAL CORTEX!!
5
Q
HVF 30-2 vs. Goldmann Full Field
- How Much VF do we have Superiorly?
- Inferiorly?
- Temporally?
- Nasally?
A
- About 70 degrees
- 60-70 Degrees
- About 100 Degrees
- About 60 degrees
6
Q
Evaluating a VF
- Viewed from Doctor/Pt Perspective?
- Blind Spot Temporal CORRESPONDS to what?
- Want to look at these VFs how?
A
- PT’s PERSPECTIVE!!
- To the NASAL LOCATION of the OPTIC NERVE!
- SIDE by SIDE!!
7
Q
Optic Nerve Defects
- What do they Follow?
- What Meridian do they RESPECT?
- They Originate from what?
- 3 Types of RNFL Defects?
A
- the Distribution of the RNFL
- HORIZONTAL MERIDIAN
- From the BLIND SPOT; NOT from FIXATION!!! (However, it doesn’t always go all the way back to the Blind Spot itself)
- 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)
8
Q
Optic Nerve Defects (2)
- 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)
A
- a. The TEMPORAL SIDE
b. CENTRAL; Centrocecal (Goes all the way to the Blind Spot), and Paracentral
9
Q
Optic Nerve Defects (3)
- Arcuate Nerve Fiber Bundles
a. Retinal Nerve Fibers from the TEMPORAL RETINA enter where on the OPTIC NERVE?
b. 3 Types of Defects seen?
A
- a. Enter the SUP and INF Poles of the OPTIC NERVE
b. Nasal Step; Arcuate Scotoma; Seidel Scotoma (Almost Comma Shaped)
10
Q
Optic Nerve Defects (4)
- Nasal Nerve Fiber Bundle
a. Fibers from the Retina NASAL to the Optic Nerve enter what side of the OPTIC NERVE?
b. Defect type?
A
- a. the NASAL SIDE!!
b. Temporal Wedge Scotoma, Arising from the Blind Spot
11
Q
- A VF Defect that goes back to the point of FIXATION is referred to as?
A
- As a RETRO-CHIASMATIC
12
Q
Optic Nerve Defects (5)
- Optic Nerve Defects should ALWAYS CORRESPOND to what?
A
- To the APPEARANCE of the OPTIC NERVE!!
13
Q
Characteristics of Lesions at the CHIASM!!!
- Temporal or Bitemporal Defects?
a. Due to involvement of what from each eye? - When will it look more ASYMMETRIC?
- A CENTRAL DEFECT in 1 EYE w/a TEMPORAL DEFECT in the OTHER EYE indicates a LESION where?
a. What is this called? - Almost ALWAYS caused by what?
A
- BITEMPORAL
a. of DECUSSATING NASAL FIBERS from each eye. - If the LESION extends more to one SIDE!!
- at the JUNCTION of the OPTIC NERVE and CHIASM!
a. a JUNCTIONAL SCOTOMA! - by a Pituitary TUMOR!!
14
Q
Nasal Hemianopia
- How common is a True Nasal Hemianopia?
a. 3 Etiologies…
A
- 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)
15
Q
Characteristics of Lesions POSTERIOR to the Optic Chiasm.
- Are they Homonymous?
- Complete or Incomplete?
- What meridian or midline do they respect?
- Where MIGHT they originate from?
- Where will they NOT originate from?
- Where is the LESION located in relation to the field defect?
A
- YES (Bi-left or bi-right)
- Either
- VERTICAL
- May originate from FIXATION
- from the blindspot
- It will be CONTRALATERAL to the Field DEFECT!
* So, Rt. Side Visual Field DEFECTS are from LESIONS on the LEFT side of the BRAIN!!!