Screening for Strabismus in Children with Down Syndrome

Rationale for Screening

The American Academy of Ophthalmology recommends the corneal light reflex test as the primary screening tool for strabismus in children with Down syndrome, due to its ease of use and minimal requirement for patient cooperation 1, 2, 4.
The corneal light reflex test is specifically designed to detect strabismus and can be performed quickly in young children or those with developmental delays, making it an ideal screening tool for this population 1, 2, 4.

Normal alignment is indicated by symmetric reflexes centered on the pupils or slightly displaced nasally in both eyes 1, 2, 4.
Esotropia (eyes turning in) is indicated by one reflex being temporally displaced 1, 2, 4.
Exotropia is indicated by one reflex being nasally displaced 1, 2, 4.
Vertical misalignment is indicated by one reflex being displaced upward or downward 1, 2, 4.

The American Academy of Ophthalmology guidelines recommend performing the corneal light reflex test first as the primary screening tool, followed by the cover test if the child can cooperate 1, 2, 4.
If the corneal light reflex test is abnormal or equivocal, the cover test should be performed to confirm the diagnosis 1, 2, 4.
Children with Down syndrome should undergo comprehensive ophthalmologic evaluation regardless of screening results, due to their increased risk of strabismus 1, 4.

Pseudoesotropia can occur in children with prominent epicanthal folds and/or a wide, flat nasal bridge, creating the illusion of esotropia when binocular alignment is actually normal 4, 5.
The corneal light reflex test can distinguish pseudoesotropia from true strabismus, showing symmetric reflexes in pseudoesotropia 4, 5.