A 3-year-old child is brought to the ophthalmology clinic by his mother with a complaint of inward turning of the right eye. On examination, the child has a 25-prism diopter esotropia with normal ocular motility and clear media. What is the most common type of strabismus in children?

Explanation

## Most Common Strabismus in Children **Key Point:** Accommodative esotropia is the most common type of strabismus in children, accounting for approximately 50% of all esotropias and 25–30% of all strabismus cases. ### Epidemiology and Characteristics | Feature | Accommodative Esotropia | Non-accommodative Esotropia | | --- | --- | --- | | **Age of onset** | 2–4 years (after accommodation develops) | Birth to 6 months | | **Frequency** | ~50% of esotropias | ~50% of esotropias | | **Refractive error** | Moderate to high hyperopia (≥+2.00 D) | No consistent refractive error | | **Response to glasses** | Reduces or eliminates deviation | No improvement with glasses | | **AC/A ratio** | Normal to high | Normal | | **Management** | Refractive correction (glasses) | Surgery | ### Pathophysiology **High-Yield:** Accommodative esotropia occurs because: 1. The child has moderate to high hyperopia 2. To achieve clear vision, the child must accommodate excessively 3. Accommodation triggers convergence via the accommodation-convergence reflex 4. Excessive convergence causes the eyes to turn inward (esotropia) **Clinical Pearl:** The onset typically occurs after age 2 years because accommodation develops fully by this age. Infants with hyperopia do not yet have well-developed accommodation, so they do not manifest esotropia. ### Management Algorithm ```mermaid flowchart TD A[Child with esotropia]:::outcome --> B{Age and onset?}:::decision B -->|2-4 years, gradual| C[Check refraction]:::action C --> D{Hyperopia present?}:::decision D -->|Yes, ≥+2.00 D| E[Prescribe glasses]:::action D -->|No or minimal| F[Consider non-accommodative]:::outcome E --> G{Deviation resolves?}:::decision G -->|Yes| H[Accommodative esotropia]:::outcome G -->|Partial/No| I[Partially accommodative]:::outcome F --> J[Surgical correction]:::action ``` **Mnemonic:** **ACHE** = **A**ccommodative esotropia, **C**hildren 2–4 years, **H**yperopia, **E**yes turn in. ### Why Accommodative Esotropia is Most Common - Hyperopia is very common in young children (present in ~8–10% of the population) - The accommodation-convergence reflex is a normal physiological response - When hyperopia is moderate to high, the accommodation demand triggers excessive convergence - Non-accommodative esotropia requires an intrinsic motor imbalance, which is less common **Warning:** Do not confuse accommodative esotropia with non-accommodative esotropia. The key discriminator is the presence of hyperopia and the response to glasses — accommodative esotropia improves significantly with refractive correction, while non-accommodative esotropia does not. [cite:Strabismus in Pediatric Ophthalmology, Chapter on Esotropia]