BVP - Optometric Management of Esotropic Strabismus - Week 5

Question 1

List six differential diagnoses for esotropia.

Answer 1

Accommodative esotropia
-including partially accommodative esotropia and accommodative excess
Non-accommodative esotropia
Pseudotropia
Infantile esotropia
Duane's syndrome
Pathological syndrome
-6th nerve palsy
-other pathological esotropia

Question 2

What is the most common strabismus?

Answer 2

Accommodative esotropia

Question 3

What are three choices a child with significant hyperopia (+3D OD, +4D OS) can make regarding their accommodative esotropia? What do children with this Rx typically choose?

Answer 3

-Relax accommodation and blurred binocular vision
-Exert accommodation by 3D and have clear vision RE
-Exert accommodayion by 4D and have clear vision LE
Typically choose to accommodate by 3D or less - clear vision with minimal effort

Question 4

With a child with the Rx +3D OD, +4D OS, who chooses to accommodate by 3D or less, what effect will the accommodation have on their fusion? what effect will this have on their left eye and what is a possible outcome?

Answer 4

The accommodation causes convergence, so she will have increased demand on fusion (divergence)
The left eye will have a blurred retinal image, causing amblyopia, decreasion fusion quality
Possible outcome is left eye esotropia driven by accommodative convergence, facilitated by left eye amblyopia

Question 5

When should spectacles be prescribed for esotropia (3)?

Answer 5

Hyperopia is over +2.00D
If esotropia responds to plus lenses (positive Raab +3.00D test)
Hyperopia is less than +2.00D, but a high AC/A ratio
-convergence excess

Question 6

What is the most important prognostic sign for optometric management of esotropia? Is this true even for hyperopia

Answer 6

Response to plus lenses

True even if hyperopia is less than +2.00D

Question 7

Are you looking for a complete accommodative component when assessing esotropia response to plus lenses?

Answer 7

No, just a significant one

Question 8

What is a way of checking esotropia response to plus lenses?

Answer 8

Raab +3.00D test

Question 9

List three complications in diagnosing accommodative esotropia at the first visit.

Answer 9

You will not necessarily find all the hyperopia at the first visit
-25-35% will show more hyperopia after wearing hyperopic spectacles for a few weeks
The esotropia may respond better to the plus after a few weeks
The motor examination is done before the cycloplegic and cannot be reliably repeated as accommodation is paralysed

Question 10

What is the gold standard cycloplegic in children under 4 and children with esotropia? List the dosage for under 6 months and older than 6 months.

Answer 10

Cyclopentolate
Under 6 months - 0.5%
Over 6 months - 1%

Question 11

Compare the effects of 2x1% cyclopentolate with 1x1%.

Answer 11

About the same

Question 12

How long do you need to wait after instilling cyclopentolate to do retinoscopy?

Answer 12

40 minutes

Question 13

Compared to cyclopentolate, how much more plus does atropine reveal?

Answer 13

0 - 0.50D

Question 14

What is a way of checking if you have found the maximum plus in a high hyperopia esotropia case?

Answer 14

Check that +0.50D over Rx reduces VA at least a line

+1.00D should bur by 3 lines

Question 15

Can maximum plus be measured on a three year old?

Answer 15

Yes

Question 16

Where should plus be put in accommodative esotropia? Explain why.

Answer 16

Accommodative esotropia has its origin in the fixating eye

Plus in front of the fixating eye will keep the strabismic eye straight

Question 17

What causes the strabismic eye to turn in accommodative esotropia? What is the implication here in terms of prescribing?

Answer 17

The accommodative effort of the fixating eye

Prescribe the full plus to the sominant eye to treat the strabismus

Question 18

In simple terms, what is happening with accommodative esotropia?

Answer 18

the child has learned to accommodate and break fusion to make the retinal image clearer in the dominant eye

Question 19

What happens to accommodative esotropia if left untreated, and how long does it take? What develops in the first few days/weeks (2)?

Answer 19

Esotropia changes from intermittent to constant over weeks/months
Suppression develops in the first few days to weeks
Amblyopia develops in the first few weeks

Question 20

What happens to the extraocular muscles (note which two) in untreated accommodative esotropia? After how long?

Answer 20

A decrease in the number and size of sarcomeres of the medial and lateral rectus muscles in the first 6-12 months

Question 21

How long does it take for anomalous retinal correspondence to develop in peripherally and centrally with untreated accommodative esotropia?

Answer 21

Peripherally in the first few weeks

Centrally after 1-2 years

Question 22

Consider a patient with changes to their extraocular muscles and anomalous retinal correspondence with untreated esotropia. How will the esotropia respond to plus lenses (2)? Explain.

Answer 22

Either:
Completely (non-accommodative esotropia)
Partially (partially accommodative esotropia)

Question 23

Can subjective refraction be done in children under 8?

Answer 23

No, not really

Question 24

In what four cases is dry retinoscopy recommended at the first visit?

Answer 24

If they have esotropia
If they are under 3 years old
If they have plus over 2.50D
If they are a spectacle virgin

Question 25

Is dry retinoscopy acceptable for review appointments?

Answer 25

Yes

Question 26

Is dry retinoscopy acceptable if the patient is wearing close to full plus? what does wearing plus do in this regard exactly?

Answer 26

Yes

Wearing plus makes the dry and wet retinoscopy the same

Question 27

Explain the following prescriptions for constant esotropia (for a child):
Full hyperopic correction
Slight overcorrection

Answer 27

Full hyperopic correction - necessary

Slight overcorrection - appropriate

Question 28

To what VA should maximum plus be pushed?

Answer 28

6/6

Question 29

Which patients should especially be pushed to maximum plus (3)?

Answer 29

Those with esotropia
Children
Those with amblyopia

Question 30

When determining maximum plus, what must you demonstrate at second and later visits?

Answer 30

That an extra +0.50D will blur

Question 31

List the five principles of treatment of any esotropia.

Answer 31

Give full plus (determined using cycloplegia)
Treat any amblyopia
Plus for amblyopic eye is for vision
Plus for the fixating eye is for the esotropia
Consider realignment for any residual esotropia after best amblyopia result and plus has been rechecked

Question 32

When is surgery for esotropia typically considered (2)? Give an example where appropriate (1). What is the aim of the surgery?

Answer 32

For where there is still a cosmetic defect despite wearing full plus
If spectacles were never tried as not likely to work
-ie. +1.00D and 50ET
Aim is to provide acceptable cosmetic appearance

Question 33

Consider a child who had surgery for esotropia. In what case would they need to wear glasses after surgery?

Answer 33

If there is more than +2.00D hyperopia

Question 34

What is the success rate of esotropia surgery long term?

Answer 34

55% with one operation