legal blindness - vision that is 20/200 or worse in both eyes (20/200 vision is the ability to see at 20 feet what a normal eye can see at 200 feet) blindness, cecity, sightlessness - the state of being blind or lacking sight.
In this review, we outlined those postural reflexes related to pathways and structures involving the cervical spine, the eyes, and the inner ear. How these structures and pathways obtain somatosensory input, interact with each other, and modulate postural changes and corrections has been described here.
The same brainstem region that gives rise to the ascending fibers of the RAS also gives rise to fibers that descend and terminate on (form synapses at) the spinal cord. These descending pathways provide facilitory signals which maintain tone of the anti-gravity or postural muscles.