A 3-year-old child is brought to the ophthalmology clinic by his mother with a complaint of inward deviation of the right eye that is most noticeable when the child looks at near objects. The left eye is straight. What is the most common type of strabismus in children?

Explanation

## Most Common Type of Strabismus in Children **Key Point:** Accommodative esotropia is the most common type of strabismus in children, accounting for approximately 50% of all esotropia cases and about 30% of all strabismus cases. ### Epidemiology and Presentation **High-Yield:** Accommodative esotropia typically presents between 18 months and 4 years of age, with peak onset around 2–3 years. It is more common in hyperopic children (refractive error of +2.00 D or greater). ### Mechanism Accommodative esotropia occurs due to the tight linkage between accommodation and convergence. When a hyperopic child accommodates to achieve clear vision, excessive convergence is triggered, causing the eyes to turn inward. The deviation is worse at near fixation and improves or disappears at distance. ### Clinical Features | Feature | Accommodative Esotropia | | --- | --- | | **Age of onset** | 18 months–4 years | | **Refractive error** | Hyperopia (≥+2.00 D) | | **Deviation worse at** | Near fixation | | **AC/A ratio** | Normal (3:1 to 4:1) | | **Response to glasses** | Significant improvement with full hyperopic correction | ### Management 1. **Cycloplegic refraction** — essential to determine true refractive error 2. **Full hyperopic correction** — first-line treatment; often resolves the strabismus completely 3. **Orthoptic exercises** — may help in mild cases 4. **Surgery** — reserved for residual deviation after optimal glasses correction **Clinical Pearl:** The AC/A (accommodation-convergence/accommodation) ratio is normal in pure accommodative esotropia, distinguishing it from non-accommodative esotropia where the ratio is high. ### Why Accommodative Esotropia is Most Common - Hyperopia is very common in young children - The accommodation-convergence reflex is physiologically tight in this age group - Non-accommodative esotropia requires neuromuscular dysfunction and is less frequent - Exotropia and vertical strabismus are less prevalent in the pediatric population **Mnemonic:** **ACHE** — Accommodative esotropia, Corrected by glasses, Hyperopia, Early onset (2–3 years).