Final answer:
An asymmetrical corneal light reflex, where the reflections in the two eyes are not aligned, is a sign of strabismus detected by the school nurse.
Step-by-step explanation:
The school nurse performing the corneal light reflex test is looking for asymmetrical reflections as a sign of strabismus. When light is shone on both corneas, the reflection of the light should be in the same spot on each eye. However, in the case of strabismus, the light reflection may be misaligned, indicating that the eyes are not looking in the same direction. This misalignment can lead to symptoms like diplopia and can be a sign of neurological problems affecting the ocular muscles or nerves.