Strabismus and Ocular Motility

Question 1

What all does the superior rectus muscle do?

Answer 1

elevates (primary action), adducts and intorts

Question 2

What all does the inferior rectus muscle do?

Answer 2

depresses, adducts and excyclotort

Question 3

WHat does the inferior oblique do?

Answer 3

elevates and extorts

Question 4

What is duction?

Answer 4

movement of one eye

Question 5

What is version?

Answer 5

movement of both eyes (conjugate)

Question 6

What is vergences?

Answer 6

disconjugate movement of eyes

Question 7

What is strabismus?

Answer 7

misalignment of visual axes

Question 8

What is phoria?

Answer 8

latent deviation that appears only when fusion is disrupted

sometimes deviated

Question 9

What is tropia?

Answer 9

manifest deviation, beyond the range of fusional control

always deviated

Question 10

What can you use the corneal light reflex for>

Answer 10

to determine if the eye is deviated in a particular direction based on where the light reflex shows up

Question 11

How can you determine if someone has a tropia?

Answer 11

use cover-uncover test and if eye deviates with covering then you have a tropia

Question 12

How can you tell if someone has phoria?

Answer 12

use the cross cover test. You do the cover uncover test and nothing happens but when you cover one eye and then cross horizontally to the other eye, the eye deviates which lets you know that the deviation is there only SOME of the time, thus it is a phoria.i.e when you break fusioN!

Question 13

What is esotropia?

Answer 13

nasalward deviation of eye “crossed eye”

Question 14

What is exotropia?

Answer 14

temporal deviation “wall eyed”

Question 15

What is hypertropia?

Answer 15

vertical deviation, relative to higher eye

Question 16

What is this:
angle of devation remains constant regardless of direction of gaze, range of motion of eyes is full, wihout limitations or restrictions.
When is this most commonly seen?

Answer 16

concomitant deviation

in childhood onset strabismus

Question 17

What is this:
Angle of strabismus varies with gaze diraction; limitation of ocular movements. Patient may exhibit abnormal head posture to maintain binocularity.
Is this congenital or acquired?

Answer 17

incomitant deviation

may be congenital or acquired

Question 18

How do you get comitant deviations?

Answer 18

abnormalities of binocularity, motion processing, poor fusional vergences

Question 19

How do you et incomitant deviations?

Answer 19

developmental (Duanes, Browns), neurological (cranial nerve palsy, myasthenia), restrictive (trauma, thyroid disease)

Question 20

How do you measure the angle of deviation?

Answer 20

with prisms

Question 21

What does the motility evaluation test?

Answer 21

ductions and versions

Question 22

What does sensory testing check out?

Answer 22

assess binocularity

Question 23

What are the different kinds of comitant strabismus (4)?

Answer 23

pseudoesotropia
congenital esotropia
accomodative esotropia
exotropia

Question 24

What is this:

wide flat nasal bridge and epicanthal folds, normal alignment by light reflex and cover tests.

Answer 24

pseudoestropia

common in infants

Question 25

What is this: large angle deviation, cross fixation, limitation of abduction may be confused with congenital 6th nerve palsy, usually requires surgical treatment

Answer 25

congenital esotropia

Question 26

What is this: over-convergence related to accomodation in hyperopia, usual age of onset 2-3 years, usually treated with glasses, bifocals sometimes necessary

Answer 26

accomodative esotropia

Question 27

What is this: Usually intermittent in childhood; normal binocular function when eyes straight; eyes deviate with fatigue or inattention

Answer 27

exotropia

Question 28

What are the three developmental incomitant stabismus?

Answer 28

Duanes' retraction syndrome Mobius Syndrome Brown's Syndrome

Question 29

What is this: absence of 6th nerve nucleus resulting in deficient abduction, miswiring of third nerve result in cocontraction of medial rectus and lateral rectus with globe retraction on adduction.

Answer 29

Duane's Retraction Syndrome

Question 30

What is mobius syndrome?

Answer 30

congenital bilateral 6th and 7th nerve palsies

Question 31

What is brown's syndrome?

Answer 31

abnormality of trochlear pulley, congenital or acquired, deficit of elevation of eye in adduction

Question 32

What are the three types of restrictive strabismus?

Answer 32

congenital fibrosis syndrome grave's disease orbital fractures

Question 33

What can cause this: | autosomal dominant, inelastic muscles and ptosis, positive forced ductions.

Answer 33

congenital fibrosis syndrome

Question 34

What can cause this: lymphocytic infiltration and secondary fibrosis of extraocular muscles in thyroid disease, enlargement of muscles may cause compression of optic nerves and vision loss, IR and MR most commonly affected

Answer 34

graves' disease

Question 35

What can orbital fractures cause?

Answer 35

scarring/entrapment of orbital tissue/extraocular muscles

Question 36

What are the five ways you can get neurologic strabismus?

Answer 36

``` cranial nerve palsies third nerve palsy fourth nerve palsy sixth nerve palsy myasthenia gravis ```

Question 37

What will cause cranial nerve palsies?

Answer 37

microvascular problems, tumor, trauma, aneurysm.

Question 38

What happens if you have third nerve palsy?

Answer 38

``` your eye is down and out Ptosis pupillary involvement (dilation) ```

Question 39

What happens if you have fourth nerve palsy?

Answer 39

oblique diplopia and torsion, bilateral often secondary to trauma (nasal upshoot)

Question 40

What happens if you have 6th nerve palsy?

Answer 40

abduction deficit, face turn to affected side (one eye looks cross eyed)

Question 41

WHat happens with myasthenia gravis? Why? What happens when the patient gets tired?

Answer 41

variable strabismus and ptosis because of acetycholine antibodies that cause muscle weakness it gets worse

Question 42

How do you test for myasthenia gravis?

Answer 42

tensilon test

Question 43

What are the three types of strabismus surgery?

Answer 43

recession resection transposition

Question 44

What surgery will weaken the effect of the muscle operated on?

Answer 44

recession

Question 45

What surgery will enhance the effect of the muscle operated on?

Answer 45

resection

Question 46

What surgery will shift force vectors of muscle?

Answer 46

transposition

Question 47

What is binocular vision?

Answer 47

fusion of images from both eyes

Question 48

What is sterposis?

Answer 48

high grade of fusion that gives depth