Seen from the side the brain can be drawn with one line. Below the brain is the eye.

The long pathways from the eyes to the V1 cross the lower part of the brain.

Half way between the eyes and the V1 there is the lateral geniculate nucleus (LGN).

A part of the nerve fibres leave the main, retinocalcarine pathway before the LGN and go the superior colliculus (SC) and a number of other nuclei. Via the pulvinar nucleus (P) visual information reaches the cortex without form analysis in the V1 and other occipital visual centres.

If there is damage to the visual pathway after the LGN, it is possible that the person/child has useful visual information for orientation in space and for eye-hand coordination despite very poor or even non-measurable visual acuity.

See the video.