Esotropia

Question 1

What is infantile esotropia?

Answer 1

• A large, constant eso deviation
• Onset: 2–4 months of age
• Often familial
• May show cross fixation
• Associated with oculomotor abnormalities and nystagmus

Infantile esotropia is characterized by a significant inward turning of the eye that is present from a young age.

Question 2

What is cross fixation?

Answer 2

The child uses the right eye to look left and left eye to look right

This is an abnormal eye movement pattern often seen in certain types of strabismus.

Question 3

What is acquired esotropia?

Answer 3

Eso deviation developing after infancy

This condition has multiple subtypes based on the underlying cause.

Question 4

What is accommodative esotropia?

Answer 4

Eso deviation caused by excess accommodation, typically in:
* Hyperopic children
* Onset ~2–3 years

This type of esotropia occurs when the eye turns inward due to the effort of focusing.

Question 5

Why does accommodative esotropia occur?

Answer 5

• Hyperopia → increased accommodation
• Increased convergence (via AC/A ratio) → eso deviation

The relationship between accommodation and convergence is crucial in understanding this condition.

Question 6

How is accommodative esotropia managed?

Answer 6

• Full hyperopic correction (glasses)
• Reduces accommodative demand
• Reduces convergence

Corrective lenses are essential in managing this condition.

Question 7

What is non-accommodative esotropia?

Answer 7

Eso deviation:
* Not related to accommodation
* Onset after ~6 months
* Does not respond to glasses

This type of esotropia is independent of refractive errors.

Question 8

What is acute esotropia?

Answer 8

Sudden onset esotropia → urgent referral required

This condition may indicate underlying neurological pathology.

Question 9

What is mechanical esotropia?

Answer 9

Eso caused by physical restriction of eye movement, e.g.:
* Duane’s syndrome

This type of esotropia is due to anatomical issues affecting eye movement.

Question 10

What is secondary esotropia?

Answer 10

Eso that develops due to another underlying condition

This condition is often a result of other health issues affecting vision.

Question 11

What is sensory esotropia?

Answer 11

Reduced vision in one eye (e.g. cataract) → loss of fusion → eye turns inward

This type of esotropia occurs when one eye has significantly poorer vision.

Question 12

What is consecutive esotropia?

Answer 12

Eso occurring after overcorrection of exotropia

This condition can arise from surgical interventions that were intended to correct outward turning of the eye.

Question 13

What is microesotropia?

Answer 13

Small-angle eso
* Often unnoticed
* Onset before ~3 years
* Usually unilateral and constant

This condition may not be easily detected due to its subtlety.

Question 14

What is monofixation syndrome?

Answer 14

One eye fixates with fovea
* Other eye uses peripheral retina only
* Limited binocular function

This syndrome indicates a lack of proper binocular vision.

Question 15

How is monofixation syndrome detected?

Answer 15

• 4Δ prism test
• Bagolini lenses

These tests help assess the degree of binocular function.

Question 16

What are risk factors for strabismus?

Answer 16

• Genetic / family history
• Developmental conditions:
  
  • Down syndrome
  • Cerebral palsy
• Birth factors:
  
  • Prematurity
  • Low birth weight

These factors can increase the likelihood of developing strabismus.

Question 17

When does strabismus most commonly present?

Answer 17

Most common → early childhood (~3 years)

Strabismus can occur at any age but is most frequently diagnosed in young children.

Question 18

Why can strabismus appear in adults?

Answer 18

• Neurological injury
• Decompensation of a latent deviation (decompensating heterophoria)

Adult-onset strabismus can arise from various health issues.

Question 19

What are the main subtypes of accommodative esotropia?

Answer 19

• Fully refractive accommodative esotropia
• Partially refractive accommodative esotropia
• Convergence excess esotropia (high AC/A)

Each subtype has distinct characteristics and management strategies.

Question 20

What is fully refractive accommodative esotropia?

Answer 20

Eso deviation caused entirely by uncorrected hyperopia
* Fully resolves with full hyperopic correction
* Does not require surgery

This type of esotropia is completely reversible with proper lens correction.

Question 21

What is the treatment goal in fully accommodative esotropia?

Answer 21

• Prescribe full cycloplegic hyperopic correction
• Eliminate deviation
• Assess binocularity and stereopsis

The aim is to restore proper alignment and visual function.

Question 22

What is partially refractive accommodative esotropia?

Answer 22

Eso deviation where:
* Hyperopic correction reduces but does not eliminate the deviation
* Residual eso remains

This condition requires ongoing management even after correction.

Question 23

How is partially accommodative esotropia managed?

Answer 23

• Full hyperopic correction
• Add base-out prism for residual deviation
• Consider surgery if deviation persists
• Glasses still required post-surgery

Management may involve multiple strategies to achieve optimal alignment.

Question 24

What is convergence excess accommodative esotropia?

Answer 24

Eso deviation:
* Much greater at near than distance
* Due to high AC/A ratio
* Excessive convergence with accommodation

This condition is characterized by a significant difference in alignment based on distance.

Question 25

How is **convergence excess esotropia** managed?

Answer 25

* Full hyperopic correction * Near add (bifocals / PALs) to reduce accommodative demand * Prism for residual deviation * Surgery not first-line ## Footnote Management focuses on reducing the need for excessive convergence.

Question 26

Why are **bifocals** used in convergence excess?

Answer 26

They reduce accommodation at near → reduces AC-driven convergence → decreases near eso deviation ## Footnote Bifocals help manage the excessive convergence associated with this condition.

Question 27

How should **bifocals** be fitted in children with esotropia?

Answer 27

Segment height at lower pupil margin ## Footnote This ensures that the child effectively uses the near segment of the lenses.

Question 28

How are **progressive lenses** fitted in these patients?

Answer 28

Fitting cross 2–4 mm above pupil ## Footnote This positioning improves access to near/intermediate zones.

Question 29

How are **prisms** used in accommodative esotropia?

Answer 29

Base-out prism to reduce convergence demand * Can be: * Split between both eyes * Placed in non-dominant eye ## Footnote Prisms are a common tool in managing strabismus.

Question 30

What evidence supports **bifocals vs PALs** in convergence excess?

Answer 30

Both are equally effective in improving: * Alignment * Stereopsis ## Footnote Research indicates that both types of lenses can be beneficial.

Question 31

What are the **six key factors** to consider when managing esotropia?

Answer 31

* Refractive error and visual acuity * Aniseikonia (image size difference) * Angle of deviation at distance * Angle of deviation at near * Motor fusion (alignment ability) * Sensory fusion (binocular integration) ## Footnote These factors are crucial for effective management of esotropia.

Question 32

Why is **refractive error** the first step in esotropia management?

Answer 32

Because uncorrected refractive error (especially hyperopia) drives accommodation → convergence, which can directly cause or worsen esotropia ## Footnote Addressing refractive errors is essential for effective treatment.

Question 33

How should **refractive error** be assessed in esotropia?

Answer 33

Using cycloplegic refraction to fully relax accommodation and reveal true hyperopia ## Footnote This method ensures accurate measurement of refractive errors.

Question 34

What aspects of **refractive error** must be corrected?

Answer 34

* Hyperopia → reduce accommodative convergence * Astigmatism → improve image clarity * Anisometropia → balance accommodation between eyes * Aniseikonia → equalise image size ## Footnote Correcting these aspects is vital for visual function.

Question 35

Why is **constant spectacle wear** important in children?

Answer 35

Maintains stable alignment and consistent visual input, preventing decompensation ## Footnote Regular use of corrective lenses is crucial for managing strabismus.

Question 36

How is **distance esotropia** managed?

Answer 36

Stepwise approach: * Fully correct hyperopia * Add base-out prism if needed * Monitor for prism adaptation * Consider surgery if not controlled ## Footnote A systematic approach is essential for effective management.

Question 37

What is **prism adaptation**?

Answer 37

When the visual system adapts to prism and the deviation reappears → reducing effectiveness ## Footnote This phenomenon can complicate the management of strabismus.

Question 38

Why must **ARC** be considered before surgery?

Answer 38

Because abnormal retinal correspondence may have adapted to misalignment → surgery can disrupt this and affect binocular outcomes ## Footnote Understanding ARC is crucial for surgical planning.

Question 39

How is **near esotropia** managed?

Answer 39

Stepwise approach: * Correct hyperopia * Allow adaptation to correction ± prisms * Assess for ARC * Prescribe bifocals if needed ## Footnote Similar to distance esotropia, a structured approach is important.

Question 40

Why are **bifocals** used in near esotropia?

Answer 40

They reduce accommodation at near, decreasing AC-driven convergence ## Footnote Bifocals help manage the convergence associated with near vision tasks.

Question 41

Why shouldn’t **bifocals** be prescribed immediately?

Answer 41

Because: * Must first correct hyperopia * Allow adaptation * Rule out ARC ## Footnote This ensures appropriate treatment and avoids over-correction.