A 7-year-old girl has alternating exotropia with a deviation of 35 PD at distance and 20 PD at near. Stereopsis is reduced. She demonstrates the 'basic' type of intermittent exotropia (XT distance/near ratio close to 1). Before considering surgery, the most appropriate first-line non-surgical approach is:

• A Orthoptic exercises (fusional convergence exercises and pencil push-ups) with part-time occlusion ✓
• B Prism adaptation test followed by base-in prism spectacles
• C Botulinum toxin injection into lateral rectus muscles bilaterally
• D Immediate bilateral lateral rectus recession

Explanation

Intermittent exotropia management is initially non-surgical: orthoptic exercises (convergence training, pen-to-nose fusional exercises) combined with part-time occlusion of the non-deviating eye (which disrupts suppression and encourages binocular fusion) are first-line in children with adequate cooperation. Prism prescription is considered but can lead to prism adaptation. Surgery is indicated when the deviation is constant, increasing, causing diplopia, or failing conservative management—but not as the first step. Botulinum toxin is a secondary option with short-lived effects.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.