A 4-year-old girl has a right esotropia of 25 prism dioptres in primary position. Abduction of the right eye is markedly limited, while adduction appears full but causes marked narrowing of the right palpebral fissure with retraction of the globe. Abduction saccades of the right eye are slow. What is the most likely diagnosis?

• A Duane retraction syndrome, type I, right eye ✓
• B Congenital sixth nerve palsy of the right eye
• C Brown syndrome of the right eye
• D Medial rectus contracture following prolonged esotropia

Explanation

Duane retraction syndrome type I shows defective abduction with intact or mildly limited adduction, and the hallmark is globe retraction with palpebral fissure narrowing on attempted adduction due to co-contraction of medial and lateral rectus. Slow abducting saccades are typical. Sixth nerve palsy limits abduction too, but it does not cause fissure narrowing or globe retraction on adduction, which is the single finding that kills that distractor. Brown syndrome restricts elevation in adduction, not horizontal movement.

Reference: Khurana AK, Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.