We now come to the part of the Bates method aimed at improving the use of the extrinsic muscles. Tracking, searching, and scanning are helped by the techniques covered in the chapters on mobility; fusion techniques, given here, will improve control of the visual axes.
Together with the accommodation drills to be described later, fusion techniques come as close as anything else in the Bates method to what is normally understood by the term “eye exercises”. In one sense they are indeed eye exercises, because the extrinsic muscles and the mechanism of accommodation are strengthened by them, but to say that they are nothing more is to simplify what they achieve. They make use of conscious control in order to improve control on the unconscious plane. This principle is basic to the whole of the Bates method, and runs through nearly every one of its techniques.
Fusion drills are very simple. The first may be used as a test to determine whether your fusion (control of the visual axes) is faulty and needs further work.
Pencil fusion
Take a pencil and hold it up straight in front of you and about 45 centimetres (18 inches) from your face. Look at the pencil, and then allow your eyes to refocus in the distance beyond it (on the far wall if you are indoors). You should now be able to see two blurred pencils, like gateposts one on either side of the point you are looking at. The two pencils should be equally plain. If they are not, if you can only see one, or if the point in the distance also appears double, then your fusion is certainly faulty.
If you can only see one pencil, shut either eye alternately to find out which is the weaker. Now cover the stronger eye and look at the pencil again. Refocus in the distance and memorise where the pencil comes in relation to the distant view. Uncover the stronger eye. Does it dominate the weaker one completely; does the pencil immediately switch sides? Or are you able to retain the weaker eye’s pencil, at least for a moment or two?
Similarly, practise covering the stronger eye if both pencils are visible but one is clearer than the other. If the distant point is also double, practise with one eye at a time, focusing first on the pencil and then in the distance, bringing your focus back to the pencil. Repeat this routine three times with each eye, then try both together. Don’t worry if you have difficulty with this or with any of the fusion drills. They will all come eventually, aided by your progress with palming and sunning.
Once you are familiar with pencil fusion in this form, try two-pencil fusion. The following explanation sounds rather involved, but is easy to understand in practice. For two-pencil fusion you need some definite reference point in the distance: any object that will fit conveniently into the “gateway”. Hold one pencil up at arm’s length, and another a few inches from your face. Practise making two gateways, one enclosing the other and both enclosing the reference point. Aim to make each of the “four” pencils equally plain, although the nearer gateway will of course be more blurred. Now focus on the further pencil. You should find that your reference point has doubled: each of the two should appear equally plain. Bring your focus back to the nearer pencil. The far pencil should now be making a gateway, which is itself enclosed by the paired images of the reference point. Again, the paired images and the gateway should appear equally plain. Finally, focus somewhere in the middle distance, between the far pencil and the reference point, and see whether you can maintain not only both gateways but also the paired images of the reference point.
A more difficult two-pencil fusion involves focusing first on the near pencil, seeing the gateway made by the far pencil, dropping the near pencil from view, and then trying to maintain unchanged the gateway made by the far one. The same goes for dropping the far pencil and trying to maintain unchanged the paired reference point.
In another kind of pencil fusion the pencils are held side by side and a couple of inches apart. Use pencils of similar thickness but contrasting colour, say yellow and red. Holding the pencils at a convenient distance from your face, experiment until you are able to make of them a double gateway — that is, of three uprights, the central one consisting of the superimposed images of both pencils. Suppose the yellow pencil is in your left hand and the red in your right. Which colour is this central upright? If it is continuously of one colour — for example, red, corresppnding to the colour seen by your stronger (right) eye — try to change it to yellow and back again to red, and then maintain it as a continuous superimposition of both colours.
Ruler fusion
In this the alignment of the visual axes is encouraged by the use of rulers of various lengths. If you are very myopic a short ruler — say 15 centimetres (6 inches) is easiest to begin with; aim to work up to a 30-centimetre (12-inch) ruler and ultimately to a metre rule (yardstick). Conversely, if you are very long-sighted or presbyopic, start with a long ruler and work down.
For the basic ruler fusion drill, hold the ruler edge-upwards and put one end between your eyes, so that one corner is resting on the bridge of your nose and the other on the lower part of your forehead. Hold the ruler from below, with the fingers of one hand, and align it so that it points straight out in front of you. If you now focus in the distance, the ruler should seem to be making a two-sided tunnel, both sides of which should be equally distinct. Practise bringing your focus back so that the far ends of the tunnel appear to approach each other and meet.
String fusion
For this you will need a piece of string between four and eight metres (13–26 feet) long. Thin white cord is best, but any sort of string will do. Tie a loop at one end to fit a nail or hook in the wall of your room, or over the door-handle or some other convenient projection. Then tie a knot every 30 centimetres (12 inches) or so along the string. Attach a small weight (such as an old key) to the end, to stop it from straying, and your fusion string is complete.
The projection over which you hook the loop should be roughly at eye level. Hold the string taut, with it touching the tip of your nose. Try to focus halfway along the string. If your fusion is already reasonably good, you should find that the string forms an X, with the crossover at the point you are looking at. As in all fusion work, both parts of the image (in this case “both” strings) ought to appear equally plain. If you cannot see the X, lower the string a little and try again, shutting your stronger eye if necessary, as in pencil fusion. If after this you still cannot see the X, give up string fusion for a while. It is more difficult than pencil or ruler fusion; but it is also one of the most valuable fusion techniques and you should plan to return to it later and try again.
On the other hand, if you do see the X, try focusing on one of the knots. Note the appearance of the X, and move to the next knot along. Eventually you should be able to move easily from knot to knot, back and forth along the whole length of the string, keeping the X going all the time.
Focus next on a point halfway between two knots. Making sure that both strings look equal, move your focus, slowly and with control, to one of the adjoining knots and back again to the midway point. Now move your focus to the other adjoining knot, and then to the middle of the next space along. Repeat with all the knots and spaces.
Picture fusion
The idea here is like that used in the drill with two differently coloured pencils. The images of the two objects are merged to make a third image.
Turn to Figure 10a, which shows two diagonal lines. Holding the page at a comfortable distance, vary the angle between your visual axes until you see not two objects, but three, the central one being a cross. Try holding the cross steady, with all four limbs of equal length. Figure 10b makes a triangle, 10c a cross inside a circle, l0d the same thing but with a smaller circle superimposed. In l0d, try to see the “crosshairs” inside the smaller circle. Figures l0e and 10f each produce two types of merged image; in 10f you should be able to see a pair of cartoon eyes, flanked by black dots. Turn the page sideways and upside-down to recombine the images in different ways.
Figure 10: Fusion figures
Picture fusion is not easy, and if you have problems it may be helpful to use a ruler. A ruler — or batten of wood — with a non-shiny surface is to be preferred, as reflections can interfere with the correct perception of the fused image. Hold the ruler as in the basic drill, but place the far end on the page, between the two halves of the fusion picture. In this way you should be able to make them merge more readily.
The fusion pictures of Figure 10 are meant only as a suggestion: whether or not you have any drawing ability, it is more interesting to make your own. Any two images may be merged, provided their centres are not more than about five centimetres apart. Try drawing the outline of a face on one side, the features on the other, and then merge them; a monkey in a tree; a diver on a high board; a man and his hat, and so on. Or merge two real objects — buttons, coins, matchsticks. The greater the variety of the objects you use, the greater will be the benefit to your vision.