A 3-year-old boy is brought to the ophthalmology clinic by his mother with a complaint of inward deviation of the left eye noticed since 6 months of age. On examination, the child has a visual acuity of 6/6 in both eyes. The cover test shows that when the right eye is covered, the left eye moves outward to fixate, and when the left eye is covered, the right eye moves inward. The alternate cover test confirms a 25 prism diopter esotropia. Cycloplegic refraction shows +2.00 D sphere in both eyes. The child has no history of prematurity, developmental delay, or neurological symptoms. What is the most likely diagnosis?

Explanation

## Clinical Analysis **Key Point:** Accommodative esotropia is the most common form of strabismus in children, typically presenting between 18 months and 4 years of age, and is strongly associated with hyperopia. ### Diagnostic Features | Feature | Finding in This Case | Significance | |---------|----------------------|---------------| | Age of onset | 6 months | Typical for accommodative esotropia | | Cycloplegic refraction | +2.00 D (hyperopia) | Hyperopia is the primary cause | | Visual acuity | 6/6 bilaterally | Rules out sensory strabismus | | Cover test | Alternating fixation | Indicates non-paralytic strabismus | | Neurological exam | Normal | Rules out paralytic causes | ### Pathophysiology **High-Yield:** In hyperopic children, excessive accommodation is required to achieve clear vision. By the near triad (accommodation → pupillary constriction → convergence), increased accommodation triggers excessive convergence, leading to esotropia. This is **accommodative esotropia**. ### Management Approach 1. **First-line:** Full cycloplegic refraction and prescription of hyperopic correction 2. **Expected outcome:** Many cases resolve with spectacle correction alone 3. **Surgery:** Reserved for cases with residual esotropia after optimal refractive correction **Clinical Pearl:** The presence of moderate hyperopia (+1.50 to +4.00 D) in a young child with esotropia should immediately raise suspicion for accommodative esotropia. The cycloplegic refraction is mandatory because the child's accommodation can mask the true refractive error. **Mnemonic:** **ACHE** — Accommodative esotropia: Hyperopia + Convergence excess + Early onset (18 months–4 years) [cite:Parsons Diseases of the Eye 21e Ch 12]