Lecture 18 Exotropia

Question 1

Which race is Exotropia more common in?

Answer 1

Asian races

Question 2

How can you classify exotropia?

Answer 2

consecutive
secondary

primary:
constant
intermittent: near, distance, no specific
distance: true simulated
simulated: fusion, AC/A

Question 3

What are the features of primary constant XOT?

Answer 3

-rule out pathology and neurological cause
-onset: less than 2 years old
-refer to HES

Question 4

What are the features of intermittent non-specific XOT?

Answer 4

*Can occur at any viewing distance (sometimes controlled, sometimes manifest)
*Can present in any age group
*Diplopia is unlikely (usually suppression occurs)

Question 5

What are the features of intermittent distance XOT?

Answer 5

*Most common of all intermittent XOT in children
*Suppression normally occurs when manifest (diplopia is rare)
*May close one eye in bright light (sunlight)
-controlled at near, good BSV
-XOT in distance

Question 6

What is a true distance XOT?

Answer 6

-will always be a distance XOT
-good BSV at near

Question 7

What is a simulated distance XOT?

Answer 7

-holding their eyes straight at near so not to be a constant XOT

controlled by accommodation (high AC/A)

controlled by fusion

Question 8

How can you differentiate between accommodation and fusion intermittent distance XOT?

Answer 8

accommodation:
-do PCT with a +3.00 lens R and L on top of their Rx
-if angle is increased at near: simulated by accommodation

fusion:
-45 mins of occlusion
-do PCT after occlusion
-increased angle: simulated by fusion

Question 9

When is surgery considered?

Answer 9

*If an intermittent squint is decompensating
*If there are symptoms- Functional Surgery
*If cosmesis is poor and patient affected- Reconstructive Surgery

Question 10

What is the managment of cosntant XOT?

Answer 10

*Correct any refractive error
*Consider referral under 8 year old to prevent loss of BSV:
-Ocular or neurological associations
-Amblyopia
*Refer HES if adults not happy with appearance or symptomatic or older children with any risk factor that needs further investigation
*Surgery
*Botulinum Toxin

Question 11

What is the management of near XOT?

Answer 11

*Correct any significant refractive error
*Under correct small hypermetropic error
*Refer if under 8 years old-unlikely as usually older
*Refer if unconfident to HES

Base In Prisms

*Orthoptic exercises:
-For deviations measuring less than 20 dioptres
-Emphasise positive fusional amplitude
-Emphasise convergence

*Surgery /Botulinum Toxin

Question 12

What is the management of non-specific XOT?

Answer 12

*Correct significant refractive error
*Under 8 year old refer:
-Amblyopia
-Prevent loss of BSV
*Refer those that are unhappy with appearance HES-often don’t have symptoms
*Surgery
*Botulinum Toxin

Question 13

What is the management of intermittent distance XOT?

Answer 13

*Give any significant refractive error
*Refer under 8 years old to HES and state in referral well controlled at near
*Older than 8 year old ask about appearance

Timing of surgery not rush if good control at near.
Surgery if:
*Risk loss of BSV
*Risk of amblyopia
* Risk of consecutive SOT
*Surgeon won’t rush as measurements not accurate for young children.

*HES will observe to ensure control not deteriorating
*Possible temporary over-minus lenses
*Surgery
*Botulinum Toxin