Incomitant Deviations (M2)

Question 1

What is it called when the angle of deviation of the visual axes is approximately the same throughout all positions of gaze and/or with each eye fixation?

Answer 1

comitant

Question 2

What is it called when the angle of deviation is not the same throughout all positions of gaze and/or with each eye fixating (variation of at least 5pd)?

Answer 2

noncomitant

Question 3

What do noncomitant presentations suggest the presence of?

Answer 3

1. overactions and/or underactions of the EOM’s

2. lesion at the nucleus, nerve, neuromuscular junction, EOM

Question 4

What are the etiologies of EOM underactions?

Answer 4

1. trauma, weakness of muscle

2. mechanical

Question 5

What are the etiologies of EOM overactions?

Answer 5

1. mechanical - faulty insertion, contracture
2. Hering’s law of equal innervation with paresis
3. idiopathic or primary

Question 6

What are the most common etiologies of noncomitant presentations in adults?

Answer 6

1. trauma
2. vascular
3. neoplasm

Question 7

What are the most common etiologies of noncomitant presentations in children?

Answer 7

1. congenital
2. trauma
3. viral
4. neoplasm

Question 8

Are children more or less likely to show symptoms for noncomitant presentations?

Answer 8

less likely

Question 9

What should be done on evaluation of a patient with noncomitant presentations?

Answer 9

1. head posture
2. versions and ductions (with or without penlight)
3. CT in different positions of gaze
4. three-step test
5. diplopia fields (red lens test)
6. Hess-Lancaster test
7. test for cyclotorsion
8. sensory fusion testing in different positions of gaze

Question 10

When there is a muscle restriction, how do ductions compare to versions?

Answer 10

same

Question 11

When there is a muscle paresis, how do ductions compare to versions?

Answer 11

more movement on ductions than versions

Question 12

Is a increase in IOP in field of gaze seen in restriction or paresis? 1. When is the IOP greatest? 2

Answer 12

1. restriction

2. direction of limited motility

Question 13

Is the saccadic velocity testing different in restriction or paresis? 1. Does it increase or decrease? 2

Answer 13

1. paresis

2. decrease velocity in filed of limited motility

Question 14

What is the movement that can occur when one eye is occluded ad neutral density filter in front of uncovered and then eye behind occluder will gradually move down in proportion to the attenuation of light reaching the open eye?

Answer 14

Bielschowsky phenomenon

Question 15

What is the affect of DVD on ductions and versions?

Answer 15

none

Question 16

What must the difference in prism diopters be in order to have an A or V pattern?

Answer 16

10 to 15pd

Question 17

Which A and V patterns with strabismics are the most symptomatic?

Answer 17

1. V eso

2. A exo (both because inc in downgaze)