You will note that this table is the same as the one that pertained to the reading glasses described earlier.

If the two eyes have different degrees of refractive error, the Myopter lenses will normally be different also. For example:

If a +3 D add is used, this means that the user's far point (limit of clear vision) is brought in to one-third meter where the book is normally held. The book can therefore be seen without accommodation. Preferably, the book is held slightly farther away, where it is just beyond the far point. This makes the print slightly blurred and insures that the ciliary muscle is fully relaxed. As mentioned previously, researchers believe that the radial fibers exert a relaxing force in the ciliary muscle when we look at something beyond the far point. This negative accommodation is not as obvious as the forceful contraction of the ciliary muscle as it is normally used to focus on close objects, but it is important nevertheless.

Actually, the effect of the device could be obtained if a myope were to gaze at a slightly blurred distant object for long periods of time. Few people could or would want to spend their time in this way. The beauty of the Myopter is that it duplicates this relaxed condition even when the eyes are used for prolonged close work. The time spent doing close work becomes time spent relaxing the eyes.

The instrument should be used without tensing the eyes or straining to see, even though the image is blurred. The eyes themselves will make the necessary effort without any conscious attempt by the user.

Note that the selection of the Myopter lenses depends on the distance normally used for close work. As an example, the following table indicates the lenses that would completely eliminate accommodation in an emmetropic person, depending on where the close work is normally held.

Note that the numbers in the right-hand column are obtained from the bottom of the fractions in the left-hand column. This same table applies to the selection of reading glass lenses as well as Myopter lenses. As the vision improves, the Myopter lenses are changed periodically to more plus or less minus, depending on the user's refraction.

Astigmatism. Normally, small to moderate amounts of astigmatism are ignored, allowing the use of spherical lenses without a spherical correction. A simple calculation that will account for the astigmatism is to convert the astigmatism to its spherical equivalent by cutting it in half. For example, if the prescription indicates -2 D with an additional -1 D in astigmatism, this could be converted to -2.5 D as the spherical equivalent. The Myopter lenses (which are usually chosen to be 3 D more positive than the distance prescription) would thus be +0.5 D.

If the astigmatism is excessive or causes problems, a cylindrical correction can be added to the Myopter lenses. It is merely necessary to have the prescription made up on ordinary eyeglass lenses and then have an optician grind the lenses down to a twenty-millimeter diameter so they will fit snugly in the slots of the instrument. Such lenses should be rotated so that the axis is in the proper position and then spot-cemented in place to prevent rotation.

If it is felt that the astigmatism must be corrected, consideration should be given to undercorrecting it so that it will have every opportunity to improve as the myopia improves.

Other uses. The Myopter has other uses besides the control of myopia. One such use is on presbyopes. Older people require reading glasses because they can no longer accommodate sufficiently. Such glasses enable them to read without accommodation, but the eyes are still converging on the book. This greatly upsets the normal relationship between accommodation and convergence, causing eye strain and headaches in many people. By using the Myopter for reading, this eye strain can be prevented since the eyes are in a perfectly natural and relaxed condition.

Another use is for schoolchildren who find reading tiring. It is natural that reading should be tiring and difficult for many people since it is not a task for which evolution has prepared us. These children often do poorer schoolwork than they would do without these problems. Some of them become school dropouts for this reason. It has been found that using the Myopter viewer for their homework has such a relaxing effect on their eyes that they can do much better in school. To expect these children to do both their schoolwork and their homework without any relaxation of their eyes is to expect too much. Some children on this program have experienced a dramatic improvement in their grades in school.

If the instrument is dropped or handled roughly, the optical parts inside it may break or get out of alignment. Improper alignment can cause headaches or discomfort and should be corrected. The alignment can be checked by closing one eye and looking backwards through the instrument with the other eye (that is, look into the large opening at the front of the instrument). Remove the lenses when making this test. Two images will be seen. They should be on approximately the same level. One should not be considerably higher than the other since this would indicate vertical misalignment.

The eyes may be able to pull together the two vertically misaligned images, but this creates stress on the external muscles of the eyes, causing discomfort. Horizontal misalignment is not of any great importance so it does not matter if the two images are seen slightly to the side of each other, rather than being superimposed.

Although several optometrists have used the instrument successfully on their patients, I have never succeeded in persuading the optometric schools or the medical schools to give it a meaningful test on myopic children, even though these schools have clinics where the instrument can easily be tested. The eye care professions in general have ignored this new myopia prevention tool as they ignore everything that has to do with myopia prevention.