Non-Surgical Management in ET

Question 1

What are the 4 general steps for treating ET’s?

Answer 1

1) Correct refractive error
2) Treat amblyopia & visual acuities
3) Further non-surgical management (like orthoptic exercises, observation and BT)
4) Surgical Management (for correcting ocular alignment or restoring BSV)

Question 2

In Bonadede et al (2020), children with accommodative ET with <4D experienced what change in their ET?

Answer 2

Increased between the ages of 0-7yo with a decrease from 7-15yo

Question 3

In Bonadede et al (2020), children with accommodative ET with equal to or >4D experienced what change in their ET?

Answer 3

Stable between 0-7yo but with a decrease from 7-15yo

Question 4

What did Bonadede et al (2020) find about accommodative ET?

Answer 4

> 4PD = Increased
<4D = Stable
Both decreased between 7yo and 15yo

No difference between children with fully accom or partially accom ET

Question 5

When correcting refractive error in ET what do we need to consider?

Answer 5

Cycloplegic refraction and the prescription of full hypermetropic prescription that is to be worn full-time.

The adaptation period should be allowed for which is 16-18wks especially in equal to or > +5.00DS

Warn parents that deviation may increase when child tries to achieve clarity without glasses (to match the level they have with them on) so exert excessive accommodation and AC

Refractions should be repeated yearly or if there is decompensation of the ET

Question 6

What are we aiming to achieve by giving refractive correction in ET?

Answer 6

To create a clear retinal image and maintain the correct balance between accommodation & convergence

Question 7

Why should be be cautious of under correction of hypermetropia?

Answer 7

There was once evidence that hypermetropia may promote emmetropisation but risks may outweigh the benefits

Question 8

When should be prescribe Rx in ET hypermetropia in early onset ET?

Answer 8

Correct hypermetropia equal to or > +2.25DS we would prescribe Rx to correct to see if the eyes realign

Question 9

What did Hussein et al (2015) find about adherence in glasses for accommodative ET?

Answer 9

Poor adherence with Rx causes poorer BSV long-term outcomes

Question 10

How will the aims of management for patients with fully accommodative ET vary between patients?

Answer 10

Varies depending on the degree of hypermetropia present

Question 11

For patients with low degrees of hypermetropia (equal to or <3.00DS with 1DC or less) what is the aim of correcting Rx?

Answer 11

To achieve well controlled, symptom free BSV without glasses so to gradually reduce prescription to possibly discard permanently. We would reduce the prescription in 0.50DS steps whilst ensuring good binocular control at Nr and Dist and that VA is 0.2 logMAR or better.
However, the majority prefer glasses for close work due to comfort.

Question 12

For patients with high degrees of hypermetropia (>3.00DS) what is the aim of correcting Rx?

Answer 12

As glasses are required for visual purposes they may be unable to discard completely. Can help teach control of deviation for social/specific occasions if patient is keen to do this through the “misty & clear” approach but encouraging contact lens wearing may be more appropriate.

Question 13

When would we prescribe bifocals in ET?

Answer 13

For convergence-excess ET or in patients with moderate-high AC/A ratios

Question 14

What are bifocals for?

Answer 14

Use minimum plus required to render patient binocular for near viewing with max CBA

Executive bifocals (straight line across middle of lens) that bisect the pupil required, to encourage use

Question 15

How should bifocals be used in ETs with high AC/A ratios?

Answer 15

Strength of bifocal segment should be gradually reduced over time until it’s not needed by reducing in 0.50DS steps with PCT measurements with Halberg Clips being used to assess control

May be used in conjunction with bar reading

Question 16

When would contact lenses be appropriate in the management of ETs?

Answer 16

• When able to demonstrate BSV with glasses for Nr and Dist in fully accommodative ET
• Small astigmatic error
• High standard of hygiene
• Good co-operation
• Motivation from the child and parents will be elicited

Contact lenses avoid peripheral blur in contacts

Question 17

How might Miotics be used in ET?

Answer 17

For convergence excess esotropia where there’s a lot of accommodative element

Question 17

What are the advantages and disadvantages of contact lenses in ET treatment?

Answer 17

Advantage:
- More discrete than glasses
- Removes peripheral blur
- Can play sports easier
- Improved BVA & ocular alignment

Disadvantages:
- Must be older and with good hand hygiene
- More handling
- Infection risk higher
- Must be motivated to wear

Question 18

How do Miotics work in ET treatment?

Answer 18

Can cause spasm of the ciliary body resulting in increased thickness of the lens which removes the need for accommodative effort and thus removes Accomm convergence (for convergence excess ET).
However, rarely used. Often used in conjunction with orthoptic exercises &/or bifocals

Question 18

What is the Miotic used in convergence-excess ET treatment?

Answer 18

Pilocarpine (4%)

Question 19

If there’s an uncooperative patient in ET not wearing glasses, what alternative can we offer?

Answer 19

LASIK appears to be effective and relatively safe to treat accommodative esotropic children by reducing their hyperopic refractive error, however, patient selection is critical. Larger studies with longer follow-up are necessary to determine its long-term effects (Seed & Abdrabbo, 2011)

Question 20

If someone with an ET has amblyopia, how do we treat this?

Answer 20

After the review 16-18wk period for Rx we would do part-time total occlusion (PTTO) through atropine penalisation or optical penalisation. If amblyopia is present it is usually mild and part-time total occlusion should be performed in order to prevent any decompensation of the deviation.

Question 21

Once max. VA has been achieved in an amblyopic patient with an ET what do we do?

Answer 21

Once the optimum level of VA has been obtained, further treatment may not be needed, and management is confined to regular orthoptic review to reassess binocular control, yearly refractions, and continued FT-wear of glasses.

Question 22

In what type of ET is amblyopia more likely to occur?

Answer 22

More prevalent in constant strabismus and earlier-onset due to plasticity of the visual system

Less likely in fully accommodative esotropia
Strongly suspect associated microtropia

Intermittent strabismus and BSV minimises risk of amblyopia, hence the importance of restoring ocular alignment

Question 23

Why would orthoptic exercises be used in ET management?

Answer 23

• To eliminate suppression when deviation is manifest
• For fusion of diplopia and control of the deviation with glasses
• To improve CBA and negative relative convergence with glasses

Question 24

Who is suitable for orthoptic exercises in ET?

Answer 24

• Old enough and able to understand and co-operate
• Motivated and able to attend regularly
• Hypermetropia equal to or < +3.00DS
• Angle of deviation <25PD BO without glasses (usually clinically would only go up to 18PD)
• Some control evident for Nr & Dist
• AC/A ratio not too hight so <10:1

Question 25

What is anti-suppression treatment?

Answer 25

This is necessary in order for the patient to appreciate pathological diplopia when they become manifest without their glasses.

Coloured filters: example wear Red-Green goggles and get the child to fixate a light for near and dist, until can see both the red & green light. (reduce filters on sbisa bar until appreciate diplopia without)

This may be combined with a septum to dissociate the eyes.

The use of a vertical prism may be required in order to illustrate diplopia to the patient.

Example use a 10 dioptre prism to move them out of their suppression scotoma and the strength of this prism is gradually reduced until diplopia is maintained without the prism.

Question 26

What’s the purpose of fusion of diplopia as an orthoptic exercise in ET treatment?

Answer 26

For spontaneous control of deviation without glasses

• Find point of intersection & image fused
  Gradually withdraw target encouraging patient to maintain fusion but image would be blurred
• Prisms
  Reduce strength until control without
• Slow removal of glasses
  Encourage to maintain a single blurred image

Question 27

Why would we improve CBA in ET treatment?

Answer 27

To improve control of deviation

Question 28

How can we improve CBA to control a deviation in ET treatment?

Answer 28

The near BVA may be improved by the use of bar reading as an exercise without glasses. The largest print is used initially, which is gradually reduced in size. The use of additional minus lenses may improve control.

The distance BVA may be improved by the use of minus lenses in the same way as described above. These exercises may be given as a homework exercise, i.e, the use of lenses and the bar for reading, and the use of minus lenses whilst watching T.V. If prescribing as homework exercises these must be performed under close parental supervision, with the parent holding the child’s head in order to prevent cheating

Question 29

How can improving negative relative convergence be useful in ET treatment?

Answer 29

Further improvement in negative relative convergence by the use of crossed physiological diplopia may be achieved by the use of stereograms (the distance position to improve negative relative convergence) and the diploscope. Both may be given as homework exercises.

As a patient’s negative relative convergence and BVA improves, glasses may be left off for increasing periods of time until they are worn only for closework, or discarded if that is the management aim. Initially the glasses should be left off under careful parental supervision in order to ensure control of the deviation.

As treatment aims to dissociate accommodation and convergence, these should be regularly assessed throughout treatment.

Use BI-range exercises and distance stereograms with extended periods of no glasses wear

Question 30

What exercises can be used to improve fusional amplitudes?

Answer 30

Bar reading

Question 31

What exercises can be used to improve negative relative vergences and improve near CBA?

Answer 31

Distance stereograms (may be combined with +ve lenses and miotic drugs)

Question 32

How should we prescribe orthoptic exercises as homework?

Answer 32

Full explanation of aims & methods

Stress importance of close supervision throughout

Exercises should be performed regularly 2-3x daily but 5x preferable

Regular follow-up appointments are necessary and important to check exercises are being carried out correctly

Question 33

What is the aim of the “misty & clear” approach?

Answer 33

• Higher Degrees of Hypermetropia
• Achieve control of deviation for special occasions only (without glasses). Glasses will be required for acuity generally however

Question 34

What happens to the eyes during the “misty & clear” exercise?

Answer 34

The patient is instructed that if they enable objects to appear “misty” without their glasses, their eyes are straight (because they are relaxing their accommodation). If the patient tries to see objects clearly their eyes will be squinting (as they are accommodating excessively in order to see clearly and are therefore converging). This method may also be prescribed as a homework exercise.

Question 35

When should we just observe a patients progress?

Answer 35

When they have a small deviation not causing psychosocial issues but would treat amblyopia and observe until outside critical period where no longer a risk of amblyopia

Patients with ARC should also just be observed for any decompensation

Question 36

How should we treat small angle ET with abnormal correspondence?

Answer 36

Treat amblyopia where atropine may be preferable

No further treatment and AC may become well established with gross BSV and some stereopsis

Question 37

When is Botox (BT) used in ET treatment?

Answer 37

Patients with high risk of post-operative diplopia or those unsuitable for surgery (example due to poor GH), BT-injection can be used as an alternative to temporarily correct the deviation.

MR BT = look laterally, then medially, then BT injected = so need a very cooperative patient to achieve this

It’s used when unsuitable for surgery like poor GH

It can be controversial in young children as requiring repeat injections

Question 38

In acute acquired comitant ET in childhood what is intracranial disease associated with (Buch & Vinding, 2015)?

Answer 38

Intracranial disease was significantly associated with older age development of the ET (7.5years versus 3.8years)

Question 39

When is neuroimaging recommended in patients with ET?

Answer 39

In acute acquired comitant esotropia in childhood when presenting neurological signs, <+3.00DS hypermetropia or recurrent ET

Question 40

What is the aim of constant ET with and without accommodative element?

Answer 40

The aims of management varies dependent upon whether there is potential for BSV or the correction of the deviation is purely cosmetic. However, in all patients the initial aims are to obtain optimum and equal level of VA by correcting any refractive error and treat any amblyopia.

1) Obtain optimum or equal VA
2) Ensure wearing refractive correction
3) Restore BSV if possible e.g. prisms in late-onset, surgery, BT
4) Maintain abnormal correspondence if present e.g. microtropia
5) Improve ocular alignment if no potential for BSV

Question 41

What is the treatment plan for a fully accommodative ET?

Answer 41

The aims of management for patients with fully accommodative esotropia will vary depending upon the degree of hypermetropia present:

1) Correction of refractive error
2) Treatment of any amblyopia
3) Ensure good control with glasses
4) Orthoptic exercises if required?
5) Weaning out of hypermetropic prescription?

Question 42

What is the treatment plan in Convergence Excess ET?

Answer 42

1) Correction of refractive error
2) Treatment of any amblyopia
3) Obtain and maintain BSV for near and distance with optimum CBA
- Bifocal therapy + weaning out
- Orthoptic exercises to improve negative fusional reserves
- Surgery

Age of patient and ability to cooperate, size of deviation, size of AC/A ratio