168 Shifting and Swinging
If successful, the letter will appear to move up and down, and the vision will improve. The shift can then be shortened until it becomes possible to shift between the top and the bottom of the letter and maintain the swing. The letter is now seen continuously. If the method fails, rest the eyes, palm, and try again.
One may also practice by shifting from one side of the letter to a point beyond the other side, or from one corner to a point beyond the other corner.
(a) Regard a letter at the distance at which it is
seen best. In myopia this will be at the near-point, a foot or less from the face. Shift from the top to the bottom until able to see each worse alternately, when the let ter will appear blacker than beforehand an illusion of swinging will be produced.
(b) Now close the eyes, and shift from the top
to the bottom of the letter mentally.
(c) Regard a blank wall with the eyes open, and
do the same. Compare the ability to shift and swing mentally with the ability to do the same visually at the near-point.
(d) Then regard the letter at the distance, and
shift from the top to the bottom. If success ful, the letter will improve, and an illusion of swinging will be produced.
Some patients, particularly children, are able to see better when one points to the letters. In other cases