Exotropia — COMPLETE

Question 1

Exophoria decompensates gradually to…

Answer 1

IXT and then eventually CXT

Question 2

TRUE/FALSE: XT has a genetic/familial component

Answer 2

TRUE

Question 3

Infantile XT onset

Answer 3

Before 1 yr

Question 4

Non-Infantile XT onset

Answer 4

1.5 - 8 yrs

Question 5

Prevalence of XT, compared to ET

Answer 5

ET>XT
(XT: 1/4 of ET)

Question 6

Describe the RE of XT patients

Answer 6

Vary just as much as general population

Question 7

General Symptoms of XT (2)

Answer 7

1. Close one eye c sun exposure
2. Head turn

Question 8

Symptoms of CXT

Answer 8

Usually asymptomatic
Complaints typically cosmetic

Question 9

Symptoms of IXT (3)

Answer 9

1. Ocular discomfort (e.g. eyes pullin, HAs)
2. Blur
3. Diplopia

if asymptomatic, likely suppression or task avoidance

Question 10

Differential Diagnosis of XT (6)

Answer 10

1. Pseudo-XT
2. CN 3 Palsy (c MR weakness)
3. Orbital Disease (Medial Wall Tumor)
4. MG (affecting MR)
5. Duane Type 2 (bc can’t aDduct)
6. Consecutive XT

Question 11

Size of Micro-XT

Answer 11

1-5 PD

Question 12

Size of Small-XT

Answer 12

6-20 PD

Question 13

Size of Moderate-XT

Answer 13

21-40 PD

Question 14

Size of Large-XT

Answer 14

> 40 PD

Question 15

Vision Therapy is the treatment of choice for pts with ______ PD of XT

Answer 15

25 or less

Question 16

What is more common: CXT vs IXT

Answer 16

IXT

CXT is very rare

Question 17

DEXT accounts for ___% of XT’s and Distance Deviation is ____ (less than, more than, equal to) Near Deviation

Answer 17

25%
More Than

Question 18

BXT accounts for ___% of XT’s and Distance Deviation is ____ (less than, more than, equal to) Near Deviation

Answer 18

50%
Equal to

Question 19

CIXT accounts for ___% of XT’s and Distance Deviation is ____ (less than, more than, equal to) Near Deviation

Answer 19

25%
Less Than

Question 20

Describe the AC/A in a DEXT

Answer 20

HIGH

Remember: the distance is wayyy more than near, so each D of accommodation accounts for a lot of convergence

Question 21

Why are patients often misdiagnosed as Pseudo-DEXT?

Answer 21

Fusional Vergence Spasm

Question 22

How do you differentiate between a DEXT and Pseudo XT

Answer 22

Patch one eye for 30 min to break fusional vergence spasm, retest near CT. If near doesn’t change (still smaller than distance), True DEXT. If changes from initial measurement (becomes more equal to distance deviation), PseudoXT/BXT

Question 23

If XT non-comitant, expect…

(etiologies)

Answer 23

Trauma (obstetric, blunt trauma, etc.), muscle anomalies, or pathology (vascular, neoplasm, viral, or chronic)

Question 24

Most common etiologies for adult onset XT

Answer 24

1. Trauma
2. Vascular
3. Neoplasm

Question 25

Most common etiologies for *childhood* onset XT

Answer 25

1. Congenital 2. Trauma 3. Acute Viral Infection

Question 26

Typical age of onset for XT

Answer 26

18-28 months

Question 27

Intermittent divergent position is common in early infancy, but stabilizes by _____ months

Answer 27

2-4 months

Question 28

Most frequently seen sensory anomaly in XT patients

Answer 28

Suppression

Question 29

Which of the sensory anomalies is the most limiting?

Answer 29

Amblyopia

Question 30

Post-Surgical XT vs. Consecutive XT

Answer 30

Post-Surgical: uncorrected XT Consecutive: over-corrected ET

Question 31

Why are Consecutive XTs difficult to treat?

Answer 31

Usually have Paradoxical Anomalous Correspondence

Question 32

Why is pre-surgical convergence therapy controversial?

Answer 32

Some surgeons think it can overcorrect XT (to ET)

Question 33

What is the tolerance level for a patient > 10 yr old?

Answer 33

1% of the time

Question 34

What is the tolerance level for a patient < 10 yr old?

Answer 34

10% of the time, without losing visual skills

Question 35

True/False: The larger the deviation of XT, the more frequent the intermittent episodes

Answer 35

TRUE

Question 36

Best possible optical correction provides ______ for binocular vision

Answer 36

Sensorimotor stimulation

Question 37

Why is undercorrecting hyperopia/overcorrecting myopia sometimes used as an IXT treatment? What are the drawbacks of this treatment?

Answer 37

Stimulates convergence Increases risk of myopic shift :(

Question 38

T/F: Overminusing treatment for IXT does not persist after being weaned off of overcorrection.

Answer 38

TRUE; effect wears off **(overminus therapy may be limited)**

Question 39

What is the purpose of PT occlusion for XT treatment?

Answer 39

Disrupt suppression and create diplopia awareness

Question 40

Explain how increased instances of diplopia can promote alignment

Answer 40

Increased diplopia —> stimulates PFV for fusion —> promotes alignment

Question 41

What demographic of XT patients can benefit most from PT occlusion as part of their therapy?

Answer 41

Patients too young for VT or during early VT to break suppression

Question 42

Which type of XT is difficult to treat with surgery?

Answer 42

CIXT

Question 43

What is considered **cosmetic** success after XT surgery?

Answer 43

ET or XT < 15 PD

Question 44

What is considered **functional** success after XT surgery?

Answer 44

Constant tropia < 10 PD w/ peripheral fusion or small residual IXT

Question 45

Which treatment plan has the best outcome for XT?

Answer 45

Surgery + VT

Question 46

What is the “glue” that prevents post-surgical drift?

Answer 46

Sensory fusion