VF - Eye Movements 5 - Central & Peripheral Abnormalities - Week 6 Flashcards Preview

OD1 - Integrated Ophthalmic Sciences & Preclinical Optometry > VF - Eye Movements 5 - Central & Peripheral Abnormalities - Week 6 > Flashcards

Flashcards in VF - Eye Movements 5 - Central & Peripheral Abnormalities - Week 6 Deck (26)
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1
Q

What can be a cause of muscular atrophy?

A

Lack of neural innervation to the muscles. Neural diseases may result in atrophy.

2
Q

Name a consequence of orbital/periorbital fat hypertrophy.

A

The eyes bulge out, and the cornea is excessively exposed to air, possibly drying it out.

3
Q

Define proptosis.

A

When the eyes bugle out of their sockets.

4
Q

Name a cause of proptosis.

A

Thyroid eye disease

5
Q

Describe a problem that occurs if extraocular muscles are excessively hypertrophied.

A

Too large and therefore have little room to contract. Can cause proptosis.

6
Q

What neurotransmitter is used at the neuromuscular junction?

A

Acetylcholine

7
Q

Describe myasthenia gravis.

A

The neuron is fine, but the post-synaptic cleft on the muscle is widened, with fewer ACh receptors.
ACh is removed more quickly as well.

8
Q

What is eaton lambert syndrome, what is it associated with, and what is the cause.

A

An autoimmune disease, occuring when axon terminals are attacked, and is associated with carcinoma.

9
Q

Consider eaton lambert syndrome and myasthenia gravis. What does repeated stimulation result in each of these?

A

MG - leads to a fatigued response

ELS - response gets stronger - anti-fatigue effect

10
Q

3rd nerve palsy is a a common secondary complication of what disease?

A

Diabetes

11
Q

Consider an individual with 3rd nerve palsy. How are their saccades affected, what law is involved, what happens when you patch their good and bad eye, and what adjusts the seeing eye to be on target?

A

When their bad eye is patched, the good eye is too far of target, driven by Hering’s law. When the patching is reversed, the cerebellum adjusts the seeing eye to be as on-target as possible.

12
Q

What two diseases are common causes for neuropathies?

A

Diabetes and MS

13
Q

What two regions of the brain are the saccade centres found in?

A

PPRF and RIMLF

14
Q

Consider a patient with SCA2. What is their smooth pursuit like?

A

It appears to be smooth, but in reality, they are making a series of small, side to side saccades.

15
Q

What region of the brain is affected in SCA2?

A

The pons, amongst others.

16
Q

Name three common factors that affect the speed of saccades.

A

Age, sedating drugs, and lack of sleep.

17
Q

What happens when the saccade pulse is normal, but the step isnt?

A

The eyes will drift back to the centre.

18
Q

Define gaze-evoked nystagmus.

A

When a saccade tonic isnt roperly integrated, and the eyes drift back to the centre, the drive to push them out again results in gaze-evoked nystagmus.

19
Q

Name two factors that may cause gaze-evoked nystagmus.

A

Cerebellar disease, excessive alcohol consumption.

20
Q

Describe dysmetria and its cause.

A

If the cerebellum is damaged, saccades of the wrong size may be elicited.

21
Q

Describe how omnipause neurons can result in unwanted saccades.

A

Happens if they inadequately inhibit burst neurons.

Some are normal, but incessant ones are pathological.

22
Q

What effect does anorexia and anxiety have on unwanted saccades?

A

Two conditions not associated with neuropathology that result in higher rates of unwanted saccades.

23
Q

How do unwanted saccades and cognitive problems relate? Give two examples.

A

May result in someone being overly distractible, such that they cant maintain gaze on intended targets.
Includes Alzheimers and ADHD

24
Q

What is unilaterally poor tracking an indicator of?

A

May indicate an ipsilateral disease.

25
Q

Name two conditions in which good pursuit with anticipatory saccades are seen.

A

Alzheimers and schizophrenia

26
Q

Describe what good pursuit with square wave jerks looks like.

A

Actual tracking is smooth, but is incessantly interrupted by the saccadic system.

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