[...The limits of vision depend upon the degree of central fixation. A
person may be able to read a sign half a mile away when he sees the
letters all alike, but when taught to see one letter best he will be
able to read smaller letters that he didn't know were there. The
remarkable vision of savages, who can see with the naked eye objects
for which most civilized persons require a telescope, is a matter of
central fixation. Some people can see the moons of Jupiter, with the
naked eye. It is not because of any superiority in the structure of
their eyes, but because they have attained a higher degree of central
fixation than most civilized persons do.

Not only do all errors of refraction and all functional disturbances
of the eye disappear when it sees by central fixation, but many
organic conditions are relieved or cured. I am unable to set any
limits to its possibilities. I would not have ventured to predict that
glaucoma, incipient cataract and syphilitic iritis could be cured by
central fixation; but It is a fact that these conditions have
disappeared when central fixation was attained. Relief was often
obtained in a few minutes, and, in rare cases, this relief was
permanent. Usually, however, a permanent cure required more prolonged
treatment. Inflammatory conditions of all kinds, including
inflammation of the cornea, iris, conjunctiva, the various coats of
the eyeball and even the optic nerve itself, have been benefited by
central fixation after other methods had failed. Infections, as well
as diseases caused by protein poisoning and the poisons of typhoid
fever, influenza, syphilis and gonorrhea, have also been benefited by
it. Even with a foreign body in the eye there is no redness and no
pain so long as central fixation is retained.

Since central fixation is impossible without mental control, central
fixation of the eye means central fixation of the mind. It means,
therefore, health in all parts of the body, for all the operations of
the physical mechanism depend upon the mind. Not only the sight, but
all the other senses--touch, taste, hearing and smell--are benefited by
central fixation. All the vital processes--digestion, assimilation,
elimination, etc.--are improved by it. The symptoms of functional and
organic diseases are relieved. The efficiency of the mind is
enormously increased. The benefits of central fixation already
observed are, in short, so great that the subject merits further
investigation...]

- Dr. W.H. Bates, "Central Fixation"