The evolution of the human species has been going on for millions of years. For all but a tiny fraction of that time, man was a hunter and gatherer, living in intimate relationship with the landscape. Even after the coming of agriculture, indeed until the early years of this century, most human beings began their day at dawn and ended it at dusk or soon afterwards. Man is essentially a diurnal creature, and his cone-rich retina works best in sunlight. Deprived of sun, the retina eventually adapts and becomes pathologically hypersensitive to even quite ordinary light intensities.
This oversensitivity to light, or photophobia, is both a defect in itself and a sign of disorder elsewhere in the visual system. It can range from the mildest sort, such that there is a tendency to squint when facing the sun, to a serious condition in which the eyes must be permanently protected with dark glasses. In nearly every case photophobia is acquired rather than congenital, and originates in the fact that the majority of us now spend much of our lives indoors. If photophobia can be overcome the eye is relieved of a great deal of strain, and this in turn encourages normal functioning generally.
The Bates technique for alleviating photophobia is called sunning, and consists simply of taking sunshine on the closed lids. In this way the retina is accustomed to progressively brighter light, until the stage is reached where the eye can function efficiently over the entire range of normally encountered light intensities. The warmth of the sun and the therapeutic properties of its rays also have a profound and beneficial effect on the health of the eyes and on the ability to relax them.
Begin if you can by taking half a minute of sun, palm until the after-images have substantially faded, and repeat two or three times. At the next sunning session increase the period slightly and repeat it an extra time, building up over the weeks and months to a maximum of 20 minutes of sun in all.
If you are so photophobic that you find it uncomfortable to let the sun shine on your closed lids, face the brightest part of the sky that you can. At the next session approach the sun a little more, until for a brief spell you can take the sun without discomfort on the lids. If even the brightness of the sky is too much, begin with artificial light, bringing the lamp gradually closer until you feel ready to start sunning outdoors.
Sunning sessions can be held two or three times a day if desired. When there is no sun, use artificial light instead. The lamp bulb should be of the ordinary household type (150 watts), or, for preference, a 100 watt silver-backed reflector spotlight (cheaply obtainable from any lighting store). Such a spotlight is useful for other Bates work too, so it might be worth getting one if you do not already have something suitable. Do not use fluorescent light for sunning, and under no circumstances use an infrared or ultraviolet lamp.
Sit with the lamp at eye level and at a comfortable distance, bringing it a few inches closer at each succeeding session until its brightness on the closed lids approximates to that of the sun. If you prefer, position the lamp behind your shoulder, angled so that you can reflect the light into your face with a mirror held in your lap. This arrangement is not to be recommended for outdoor sunning, because reflected sunlight has slightly different properties from the real thing.
Whether you are sunning indoors or out, keep your head slowly moving so that the light is distributed evenly across each retina. The simplest way to do this is to swing the head from side to side through 90 degrees or a little more, taking about 7–10 seconds to move from one side to the other. Vary the movement if you like by swinging the head so that, if a paintbrush were attached to your nose, you would be painting a circle, an infinity sign, a figure-of-eight, or any other geometrical figure that pleases you. Every few swings, reverse the direction of travel. During sunning you should feel yourself becoming agreeably drowsy, infused by the warm glow coming through your eyelids. Let the glow spread until it seems to take over your whole body. If, however, you ever find sunning uncomfortable or unpleasant, stop immediately.
Some accounts of the Bates method mention a more advanced technique in which the sun is taken directly on the retina. This open-eyed sunning sounds more alarming than it really is. No one in his right mind would dream of staring at the sun, for this would cause severe damage to the eyes, and perhaps even blindness. Brief and extremely cautious exposure of the retina to the sun’s disc, however, is quite safe. One eye is sunned at a time, the other being covered with the hand. Turn the head quickly so that the sun sweeps across the retina (the turn of the head takes only a couple of seconds), blinking rapidly and easily as you do so. Repeat with the other eye, and then palm until all after-images have faded.
Open-eyed sunning is undoubtedly of value for some people in the later stages of their Bates training, as it removes the final traces of photophobia, but in the ordinary way its benefits are not noticeably greater than those of closed-eyed sunning, and it can cause strain. It is probably best left alone, at least to begin with. In any event it should only be used sparingly and responsibly. The technique is described here mainly for the sake of completeness.
Like palming, sunning can also be done at odd moments, whenever the opportunity presents itself and you have a few seconds to spare.
It goes without saying that, whenever possible, sunglasses are to be avoided. After Bates training you are less likely to feel the need of them anyway, but if ever you do, a wide-brimmed hat or sunshade will probably give all the protection necessary. In temperate latitudes, sunglasses are usually only needed in conditions of exceptional glare (during prolonged exposure to sunlit snow, for example); in the tropics, however, and particularly for Caucasians and others whose forebears evolved in more temperate zones, sunglasses may be required more often. In these circumstances lenses of the best quality should be used. Cheap sunglasses, besides distorting the image, cannot be relied upon to give adequate protection from excessive ultraviolet radiation.
The squinting and grimacing that accompany photophobia can become a habit that persists even after the photophobia itself has gone. Whenever you catch yourself squinting, ask yourself whether you really need to do it; allow your face muscles to relax, and take pleasure in your new and easy relationship with the sun. Squinting is not only unattractive in itself, but it also aggravates the formation of wrinkles and makes you look older than you should.
Sunning is aimed specifically at daylight vision. It is worth giving a little thought to your night sight as well, especially if your work or hobby involves vision in dim light. Once in a while, delay switching on the lamps in the evening for half an hour or longer. Notice how, as darkness gathers and the rods take over from the cones, detail and colour and, to some extent, depth perception gradually vanish.
Do not try to make out detail, because this is futile and causes strain. In fact you have a better chance of resolving detail if you do as the astronomers do when they wish to pick out a very faint star. Rather than staring straight at it, they look off to one side, allowing its light to fall outside the macula and in a part of the retina where the rods outnumber cones.