A 9-month-old boy presents with a constant esotropia noted since the first few weeks of life. Cycloplegic refraction shows hypermetropia of +1.50 D in each eye. The deviation measures 40 prism dioptres and has been unchanged across visits. Which additional finding would BEST support a diagnosis of infantile (congenital) esotropia?

• A A small angle deviation of less than 10 prism dioptres
• B Deviation greater at near than at distance by more than 10 prism dioptres
• C Resolution of the squint when full hyperopic correction is worn
• D Dissociated vertical deviation with inferior oblique overaction ✓

Explanation

Infantile esotropia presents before 6 months of age with a large (usually over 30 prism dioptres) and stable angle, low hypermetropia (typically under +2.50 A), and characteristic associations: dissociated vertical deviation, inferior oblique overaction, cross fixation, and latent nystagmus. Dissociated vertical deviation with inferior oblique overaction therefore strongly supports the diagnosis. Option B describes a high AC/D pattern typical of accommodative esotropia, and option C is exactly what rules out the accommodative type.

Reference: Parsons' Diseases of the Eye, 23rd ed.

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Written and medically reviewed by the StethoPrep medical team.