A 6-year-old girl is referred to the eye clinic for evaluation of exotropia. Her mother reports that the child's right eye drifts outward, especially when she is tired or looking at distant objects. On examination, the right eye is deviated laterally. The cover test reveals that when the right eye is covered, the left eye makes an inward movement to fixate. Visual acuity is 6/6 in both eyes, and cycloplegic refraction shows no significant refractive error. Extraocular movements are full and normal. What is the most appropriate initial management?