Neurophthalmology 2 Flashcards Preview

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Flashcards in Neurophthalmology 2 Deck (19)
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1
Q
The hallmarks of visual field defects:
A
1. The defect respects vertical and horizontal meridian (optic nerve and beyond)
2. Homonymous field loss (optic tract and beyond)
3. The defect is a combination of a homonymous field loss plus respect of the vertical meridian (optic tract and beyond)

exception is optic n defects do not always respect meridian
2
Q
If optic n dysfunction is unilateral:

A
1. monocular vision loss either due to decreased acuity, field loss or both.
2. afferent papillary defect (APD)
3. color vision loss
4. The Lateral Geniculate nucleus sees relatively less light than the other side and dilates.
3
Q
APDs occur when:
A
there is dysfunction prior to the synapse of the retinal ganglion in the thalamus
4
Q
APD is tested
A
by the swinging flashlight test:
if the light is shined at one side and both pupils constrict, then the light is shined in the other eye and it dilates, there is a APD.
5
Q
here are 4 questions that need to be addressed in a diplopia evaluation:
A
1. Is the diplopia binocular?
2. Is the diplopia horizontal or vertical?
3. Is the diplopia worse in any specific position of gaze?
4. Is the diplopia worse at near or distance viewing?
6
Q
Is the diplopia binocular?
A
If yes, then the eyes are misaligned.
7
Q
cause of misaligned eyes
A
This could be due to the NEJM of causes –
1. Nerve (3rd, 4th or 6th palsies)
2. Eye (displaced)
3. Juntion Neuromuscular (myasthenia gravis)
4. Muscle (thyroid or rare myopathies)
8
Q
Is the diplopia horizontal or vertical?
A
helps limit number of pathways involved
9
Q
Is the diplopia worse in any specific position of gaze?
A
localization
10
Q
Is the diplopia worse at near or distance viewing?
A
localization
11
Q
Oscillopia is the
A
appearance of movement in someone’s visual world due to eye movement disturbances.

The most common form is nystagmus, an involuntary rhythmic osccilation.
12
Q
2 phases in nystagmus
A
1. slow
2. fast
13
Q
3 types of oscillopia
A
1. Pendular (slow – slow)
2. Jerk (fast – slow)
3. Mixed (slow – slow and fast – slow)
14
Q
Nystagmus can be
A
1. horizontal
2. vertical
3. torsional
4. mixed
15
Q
Nystagmus is localized to the _____.
A
8th nerve or the CNS.
16
Q
Downbeat nystagmus is localized to the ____
A
cervical-medually junction causes bouncing of the eye up and down.
17
Q
Downbeat nystagmus is caused by:
A
disease of the cerebellar flocculus such as MS, Chiari malformations or tumors.
18
Q
The flocculus normally inhibits the:
A
anterior semicircular canals connections, which causes the eyes to drift upwards and require a rapid downward correction.
19
Q
anterior semicircular canals connections stimulate the eyes to ____
A
move up