6.5 Accommodative Esotropia

Definition

  • Esotropia (ET) linked to accommodation

History

  • Onset 6 months - 7 years (average 2.5 years)
  • May be intermittent at onset, (sometimes precipitated by trauma or illness) becoming constant
  • Diplopia may occur but usually disappears as the patient develops suppression scotoma
  • Approximately 75% have a family history
  • Amblyopia common (50%)
  • No associated IOOA or DVDs

Classification

Accommodative

High AC / A

Mixed (most common)

Definition

Accommodative

Hypermetropia means that a high amount of accommodation (with a proportionate amount of convergence) is required to focus even on a distant target

High AC / A

Accommodation is associated with a dis-proportionately high amount of convergence

Mixed (most common)

Hypermetropia
High AC / A

Accommodative

1.Fully accommodative
Esotropia (ET) fully corrected by full cycloplegic refraction

2. Partially / (Non)
accommodative

ET only partially corrected by full cycloplegic refraction (i.e. still ET for D&N)

Mixed (most common)

Distance prescription corrects distance deviation but a deviation remains at near

CTD / N

Accommodative

ET Distance= ET Near (within 8Δ)

High AC / A

Straight Distance (after correction), ET Near.
ET for near may be reduced or eliminated by a +3.0 add

Mixed (most common)

ET Distance < ET Near (by >8Δ)
i.e. When straight for distance with full cycloplegic correction will still have ET for near.
ET for near may be reduced or eliminated by a +3.0 add

Refraction

Accommodative

Hypermetropia (e.g. +3 to +10D)

High AC / A

Emmetropia (ranges from myopic to high hyperope)

Mixed (most common)

Hypermetropia

AC / A ratio

Accommodative

Normal (e.g. 3-5)

High AC / A

High

Mixed (most common)

High

Examination Structure

1. Visual Acuity (Best Corrected)

  • Amblyopia is common (50%, especially partially accommodative)

2. Spectacles

3. Inspection

  1. Abnormal Head Position (AHP)?
  2. Hirschberg (pupil margin=30Δ, limbus=90Δ) - Esotropia
  3. (Lids normal)
  4. (Pupils normal)
Figure 5.3.1 Anterior and Posterior Flap Options for the Various Locations of the Lid

Figure 6.5.1A
Fully Accommodative Esotropia
A: Eyes straight for distance with spectacles

Figure 5.3.1 Anterior and Posterior Flap Options for the Various Locations of the Lid

Figure 6.5.1B
Fully Accommodative Esotropia
B: Esotropia for distance without spectacles

4. Cover-Testing

  • Comitant ET (Measure distance & near as an estimation of AC / A. An ET that is greater for near than distance suggests a high AC / A, but this can only be proven by formal testing- see below)
    • A) Without glasses: CTD, CTN
    • B) With glasses: CTD, CTN
  • (NB: Attempts may also be made to measure the AC / A ratio by the lens gradient method by cover-testing at near with and without +3D lenses)

5. Ocular Rotations

  • Full ductions (Exclude CNVI palsy) ± IOOA
  • DVD is uncommon

6. Stereopsis

7. Dilated Fundoscopy

8. Cycloplegic Refraction

Often Hypermetropic. Use:

  1. Cyclopentolate 1%, (Phenylephrine 2.5%) or
  2. Atropine 1% bd for 3 days prior if dark irides, amblyopic, unsure, unco-operative

Summary

  • Fully / Partially / Non-Accommodative ET with presumed Normal / High AC / A

Investigations

Most accommodative esotropias do not require further investigations. However, neuroimaging (MRI brain) should be considered when the presentation is atypical:

  1. Acute onset
  2. Older (>7yrs)
  3. Incomitant i.e. abduction deficit
  4. Diplopia, other neurological signs (e.g. CN VI, papilloedema, nystagmus)
  5. No hypermetropia

Management

Aims:

  1. Maintain vision (Treat amblyopia / refraction)
  2. Realign the visual axes (straighten eyes for distance with spectacles)
  3. Maintain or restore good binocular function (predict fusion potential given age, duration, vision) - most get monofixation syndrome
  4. Alleviate symptoms (asthenopia,  diplopia)

Accommodative Component

High AC / A Component

Fully

Partially / (Non)

Patching

TREAT AMBLYOPIA (50% of patients)

Spectacles

Accommodative Component

Correct refraction (Cycloplegic refraction- Full time spectacle wear)

High AC / A Component

Correct refraction (get straight for distance first before any bifocals)

Spectacles

Accommodative Component

If ET for distance persists:

  1. Check spectacle prescription
  2. Repeat cycloplegic refraction (consider atropine) and prescribe any residual latent hyperopia.

If only ET for near persists (i.e. mixed), consider bifocals.

High AC / A Component

Options include:

  1. Observation if asymptomatic, cosmetically acceptable (advocates argue there is little functional disadvantage if straight for distance but ET for near).
  2. Bifocals if can correct to ET for near <10Δ with improvement in near stereopsis. Prescribe the minimum plus for close work e.g. +3D for 1 / 3m executive flat-top through pupil or short corridor wide reading-zone multifocal lens.
  • Spectacles are the mainstay of management of most accommodative esotropia
  • Prescribe spectacles prior to amblyopia patching (patch when vision plateaus)
  • Warn parents “ET will be worse without glasses” and that glasses are for alignment not vision. (If not tolerated, try g. cyclopentolate 1% or g. atropine ou daily until they can)
  • Try to wean script from 6yrs or when child complains of blurred vision (reduce in + 0.5D increments). Most patients will require spectacles until their teenage years (especially if refraction > +3D)

Accommodative Component

High AC / A Component

Fully

Partially / (Non)

Surgery

Surgery can only be considered once:

1. Refraction has been corrected for distance
2. Amblyopia has been treated (or attempted)
3. There is a stable angle of deviation

Consider surgery (only ~20% will require) if

1. There is potential for maintaining / improving binocular single vision
2. Patient or family is concerned by cosmesis and reassure them the surgery is reconstructive, not cosmetic

Accommodative Component

Only operate on non-accommodative component (make eyes straight with glasses)

  1. Bilateral MR recession (BMRR)
  2. MR recession / LR resection (if amblyopic eye)

High AC / A Component

Only operate on non-accommodative component
Options include:

  1. BMRR (operate for distance)- tends to under correct
  2. BMRR ± Augmented surgery: operate for average of D and N with bifocals e.g. 10ΔD, 30ΔN: operate for 20)
  3. BMRR (operate for near) - risks overcorrecting
  4. BMRR + Faden operation- posterior fixation suture can be used if straight for distance, ET for near i.e. high AC / A. This is often performed as a second operation → If develops consecutive XT after surgery, reduce the strength of the spectacles.
  • Follow-up at least 6-monthly (at least annual refraction)
  • Monitor for amblyopia, under-correction

Summary Management Algorithm [ii]

Courtesy of Dr Ross Fitzsimmons

Normal AC / A
(ET Distance = ET Near)

High AC / A
(ET Distance < ET Near)

Fully Accommodative

Normal AC / A
(ET Distance = ET Near)

Spectacles

High AC / A
(ET Distance < ET Near)

Bifocals

Partially Accommodative

Normal AC / A
(ET Distance = ET Near)

Spectacles + Surgery

High AC / A
(ET Distance < ET Near)

Bifocals, Surgery

Non-accommodative

Normal AC / A
(ET Distance = ET Near)

Surgery

High AC / A
(ET Distance < ET Near)

Bifocals, Surgery

Notes

1. Prism Adaptation Test

This is a method that some clinicians use to find the maximum esotropic measurement for distance prior to surgery. It is not universally used.

  1. Give full refractive correction + Fresnel prism to neutralise the distance angle
  2. Re-check after 1 Week
    • Increase in angle by >8Δ? → Repeat step 1
    • No increase in angle? → operate for prism-adapted angle

2. AC / A (Accommodative Convergence to Accommodation) Ratio

Parks Method
  • 10Δ between near and distance.

Heterophoria
  • Changes accommodation by changing the distance viewed upon (∴ IPD important)
  • = IPD + (Dn – Dd) / D

IPD

Interpupillary distance (cm)

Dn

Ocular deviation for near

Dd

Ocular deviation for distance

D

Near fixation distance in dioptres (e.g. to 1 / 3m or 3D)

(+ = esodeviation; - = exodeviation)

3. Lens Gradient Method (Used Clinically)

  • Changes accommodation by changing lenses.
  • = (D1 – D2) / D

D1

Ocular deviation without lens

D2

Ocular deviation with lens

D

Power of the lens (minus to induce accommodation, plus to relax accommodation)

Example:

  • = (45ΔET – 15ΔET) / +3D = 10
  • = (20ΔXT – straight) / -2D = 10

          

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