Squints

Question 1

What is the medical name for a squint

Answer 1

Strabismus

Question 2

What is a squint

Answer 2

A misalignment of the visual axes of the eyes

Question 3

How are squint’s named

Answer 3

If eyes turn in it’s eso-
If eyes turn out it’s exo-
If eyes go up its hyper-
Down its hypo-

Eyes may also be rotated away from each other - excyclotortsion
Towards each other - incyclotortsion

If the squint is manifest (there all the time) you add tropia to the end
If it is latent (only there on testing when binocular vision is disrupted) you add phoria

Question 4

What type of squint is more common - horizontal or vertical

Answer 4

Horizontal

Question 5

How does a squint affect the vision

Answer 5

Often leads to double vision

Question 6

What can cause a squint in children

Answer 6

Most commonly due to them being long sighted (hypermetropic)
Can be congenital
Retinoblastoma
Nerve palsy due to intracranial pathology

Question 7

How do squints present

Answer 7

Usually asymptomatic and picked up by screening

May be noticeable by looking at them but usually subtle

Question 8

What is the main risk of an untreated squint

Answer 8

Amblyopia - loss of vision in the affected eye

The brain prioritizes the good eye to avoid double vision so the proper visual pathways don’t form from the squint eye

Question 9

Squints in children can be treated up until which point

Answer 9

Around age 8

At this stage the vision is fully developed and won’t change

Question 10

How do you treat a childhood squint

Answer 10

Patching of the good eye - stimulates the squinting eye to prevent amblyopia and form the visual pathways

Give them glasses - promotes binocular vision by improving occular alignment and preventing overuse of accommodation reflex

Some may need surgery for ocular alignment - alter the muscles

Question 11

What can cause a squint in adulthood

Answer 11

Missed childhood squint presenting late 
Nerve palsy - 3rd, 4th or 6th
Trauma - eg 
blowout fractures
Muscle pathology - thyroid eye disease, Brown's, Resrtictive Duanes, MG

Question 12

How do squints present in adulthood

Answer 12

Diplopia - often disabling
Eye movement testing usually reveals some reduction in
movement in one or more directions causing the size of the deviation to vary in different
positions of gaze (an incomitant squint).

Question 13

How do you treat a squint in adulthood

Answer 13

Use a patch to eliminate double vision
Can also use a prism
Many need botox to paralyse muscle or surgery
Investigate for underlying cause

Question 14

Do squints run in families

Answer 14

They can do!

Question 15

What examinations would you do to diagnose a squint

Answer 15

Test eye movements
Cover test - when you cover the good eye the squint should correct itself
Cover/uncover test for latent squint -

Question 16

When would a childhood squint require urgent referral

Answer 16

If there are unusual features such as loss of red reflex or incomitance ( worse in certain gaze positions)

Question 17

How does a latent squint present

Answer 17

Typically asymptomatic
Only picked up on testing - interrupt binocular vision by covering one eye (cover/uncover test)
Can become symptomatic if it decompensates to a manifest squint - patient is tired or unwell

Question 18

What is the medical name for a lazy eye

Answer 18

Amblyopia

Question 19

Most convergent squints are corrected by glasses - true or false

Answer 19

True

Question 20

Why does long-sightedness cause squints in children

Answer 20

They get an esotropia (eye turns in) as they try and use the accommodation reflex to correct their vision
Overaccommodation and overconvergence

Question 21

Which squint patients require surgery

Answer 21

Large infantile squints - for aesthetic reasons
Significant residual squints
If there is a chance of restoring binocular vision

Question 22

What are the main types of squint surgery

Answer 22

Recession –reattach muscle posterior to insertion. (weakens muscle)

Resection –Excise a segment of muscle (strengthens muscle)

Question 23

What can cause an opacity in the red reflex of the eye

Answer 23

Cataracts

Question 24

What can cause an alteration in the colour of the red relfex

Answer 24

Pale yellow - asymmetrical camera angle (flash hits differently), retinoblastoma or coloboma
Black/no reflex - retinoblastoma, retinal detachment