A 4-year-old boy is brought to clinic for evaluation of crossed eyes. The mother noticed that the patient's left eye has been very slightly deviated toward the nose over the last few months. The patient has no chronic medical conditions and takes no medications. Vaccinations are up to date. Visual acuity screen reveals 20/20 and 20/50 in the right and left eyes, respectively. Corneal light reflex is central in the right eye and temporal in the left eye. When the right eye is covered, the left eye shifts fixation from a nasal to temporal direction. When the left eye is covered, the right eye remains in midline position. Red reflex is more intense in the left eye. Dilated funduscopic examination is normal bilaterally. In addition to corrective lenses, which of the following is the best next step in management of this patient?
Strabismus (ocular misalignment) | |
Clinical findings |
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Treatment |
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Complications |
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This patient has strabismus, which is ocular misalignment characterized by nasal (esotropia) or temporal (exotropia) deviation of the eye. Intermittent strabismus can be expected in infants age <4 months due to immature extraocular muscles (ocular instability of infancy). However, strabismus beyond early infancy must be treated to prevent amblyopia, a functional reduction in visual acuity from disuse of the deviated eye, as seen in this patient.
Examination findings in strabismus include asymmetric red reflexes and corneal light reflexes as well as eye deviation during the cover test. The cover test is performed by covering one eye and observing for movement in the other while the child focuses on an object. A normal eye maintains the same position without moving; a misaligned eye shifts to refixate on the object when the normal eye is covered.
Treatment involves prescription eyeglasses for correction of significant refractive errors (if present) and promoting the use of the affected eye. For example, the amblyopic eye can be strengthened by patching the normal eye or blurring the vision of the normal eye with cycloplegic drops (eg, atropine). Without treatment, this patient's visual acuity in the left eye will continue to worsen (Choice C). Screening for strabismus should be performed at every well child visit until age 5 because treatment outcomes are best when initiated while the visual cortex is most malleable.
(Choices A and B) Latanoprost drops are used to reduce increased intraocular pressure seen with glaucoma, which causes tearing, corneal edema, and (rarely) strabismus due to vision loss. Optic disc cupping would be present on funduscopic examination in a patient with glaucoma.
(Choice D) This patient's left eye is deviated with vision loss; patching the left eye will worsen the amblyopia.
Educational objective:
Strabismus, or ocular misalignment, can be detected by asymmetric red and corneal light reflexes as well as eye deviation on cover test. Management includes correction of refractive errors and strengthening the affected eye by patching or applying drops to blur vision in the normal eye. Without treatment, strabismus can lead to amblyopia, a functional reduction in visual acuity of the deviated eye.