A 4-year-old girl is brought to the clinic for a routine well-child examination. During the visit, her mother mentions that the child’s right eye occasionally appears to "turn in" toward her nose, particularly when she is tired or focusing on small objects. On physical examination, the corneal light reflex is centered in the left eye but is displaced laterally on the right cornea. When a cover-uncover test is performed, the right eye moves outward to fixate on a target when the left eye is covered. Visual acuity is 20/20 in the left eye and 20/60 in the right eye. Funduscopic examination is unremarkable in both eyes, and the red reflex is symmetric and normal.
Which of the following is the most appropriate next step in the management of this patient’s condition?
The correct answer is:
C) Patching of the left eye
The patient is presenting with strabismic amblyopia, a functional reduction in visual acuity caused by the brain ignoring input from a misaligned eye to avoid diplopia. This leads to impaired development of the visual cortex corresponding to the deviating eye. The diagnosis is supported by the abnormal cover-uncover test (esotropia) and the significant difference in visual acuity (anisometropia) despite a normal funduscopic exam. The most appropriate next step in management is to force the brain to use the weaker eye by patching the unaffected eye (in this case left eye). Patching therapy is most effective when initiated early in the critical period of visual development (typically before age 7–10 years).
Answer choice A: Atropine drops in the right eye, is incorrect. Penalization therapy with atropine drops is an alternative to patching. However, the drops must be placed in the unaffected eye to blur its near vision, thereby forcing the brain to utilize the weaker (right) eye. Placing atropine in the right eye would further impair its function and worsen the amblyopia.
Answer choice B: Observation and reassessment in 1 year, is incorrect. Amblyopia is a time-sensitive condition. Delaying treatment during the critical period of neuroplasticity can lead to permanent, irreversible vision loss in the affected eye.
Answer choice D: Patching of the right eye, is incorrect. Patching the right eye (the weaker eye) would be counterproductive, as it would continue to allow the brain to rely solely on the left eye, reinforcing the suppression of the right eye's visual pathways.
Answer choice E: Surgical recession of the medial rectus muscle, is incorrect. While surgery may be indicated to correct the physical misalignment (strabismus) and improve binocularity, it does not treat the underlying amblyopia (the cortical vision loss). Visual acuity must be addressed first or concurrently with patching or penalization. Surgery alone will not improve the 20/60 vision in the right eye.
Key Learning Point
Amblyopia is a functional reduction in visual acuity caused by abnormal visual development early in life, most commonly due to strabismus, refractive errors, or visual deprivation. Treatment involves correcting any underlying refractive errors and forcing the use of the amblyopic eye by patching or blurring (penalization with atropine) the stronger, non-amblyopic eye.
