An 8-month-old infant has a constant esotropia of 40 prism diopters with cross-fixation and no significant refractive error. To maximise the chance of developing binocular single vision, surgery should ideally be performed:

• A Between 6 months and 18 months of age ✓
• B After 4 years of age once cooperation allows accurate measurements
• C Only after a trial of botulinum toxin fails
• D At any age, since sensory outcome is independent of timing

Explanation

For infantile esotropia, alignment achieved early, generally between 6 months and 18 months of age, gives the best chance of peripheral fusion and gross stereopsis because the visual cortex retains enough plasticity within this window. Waiting until school age forfeits this opportunity even if the cosmetic result is identical. Botulinum toxin may be used as an alternative but is not a prerequisite, and late surgery cannot restore the critical period that has been missed.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.