Some retinal conditions are known to be inherited, and show up in families generation after generation. It is worthwhile, therefore, to give a brief description of how the inheritance of abnormalities works.

At a distance, a group of naked human beings would always appear more or less similar, once allowances for differences in age, sex and race have been made. But the closer we get to such a group the more discrepancies we begin to notice. Even without using specialized equipment we can discern that every individual is different, every individual has his own particular characteristics. No two people have the same fingerprints, to use the most famous criterion, and with modern techniques of tissue analysis and cell analysis the variations from one human to another become even more apparent. And yet, within the human individual, when one cell dies and is replaced by another, the new one is identical to the old. The fertilization of the human egg by a male sperm results in a mixing up of the essential inheritance particles (genes) that determine the structure of every cell in our body so that, although one cell in a son’s body may be identical to the equivalent cell in his father’s, it is combined with other cells which derive from his mother. Everybody then is a composite (roughly fifty-fifty) of both parents’ cells, the manufacture of which is computerized from data held in the molecules of the original egg and sperm. This data is `printed’ on nucleic acid proteins (DNA), and in the normal course of events cannot be altered. The genes I have inherited from my parents (and in neither case do I inherit all their genes) are precisely and only those genes I have to give my children. But the way my genes ‘programme out’, the building that is made from the inviable blueprint, can be affected, and by different kinds of factor. The programme can be modified by external forces such as drugs, viruses and diet.

This at least is the orthodox neo-Darwinian view. Acquired characteristics cannot be inherited. If I lose my arm in an accident my children will nonetheless have two arms. Similarly, if I suffer some debilitating disease in my youth, the effects of that disease will not be passed on (unless of course I still have the disease, am a woman and pass it on to my child through the normal channels of contagion). Conversely any inherited defect I may have may very well pass down to my children, either overtly or covertly. However, recent scientific technology has explored ways of altering the blueprint itself, of restructuring the basic genetic code, using various forms of light-ray and chemical. While in the distant future this research may result in doctors being able to correct a hereditary defect, for the present it remains the case that both genes and cells naturally tend to reproduce facsimile versions of themselves. In the case of cell- production, however, modern medicine has identified many diseases which interfere with the natural process. Cancer, for example, radically alters the body’s ability to go on reproducing the same kind of cell year after year. Cell-production is also affected by age. As the body grows old it sometimes ceases to reproduce certain cells, while other cells are badly reproduced. And of course there are some cells, including many in the eye, that are only produced once (before or at birth), and which have to last a lifetime. As life expectancy increases, such cells are put under more and more pressure.

How, it may be asked, if the basic tendency of cells is to replicate themselves perfectly, did we evolve from the amoeba? The answer seems to lie in genetic mutations, which occur either spontaneously or, at an earlier period in the earth’s history, as the result of interference on the primitive genetic soup of one- cell organisms by sunrays that were able to penetrate a much thinner atmosphere. As a rule, the more complex an organism is, the greater the change effected by just one alteration in the genetic coding, for in the print-out of the genetic programme the genes act collectively, not simply. Thus among humans, for example, a gene for a longer leg tends also to mean a gene for a longer arm. The amazing thing, perhaps, is not so much the evolution of species, but the relative stability of species at any one point in their development.

The consequence of such stability is that while it ensures the inheritance of survival-fit characteristics, it also ensures the inheritance of any defects that are not absolutely unlivable- with. And of course, civilization and modern medicine often enable a defect to survive into adulthood, and therefore be able to reproduce itself, where in a primitive environment it would quickly have become extinct.

The theory of human abnormalities is complex and at times uncertain. Can behavioural defects, for example, be inherited? And then there is the question of recessive or throw-back genes. In this case a bad characteristic is clearly inherited, but often across two or more generations, so that the intervening generation is not affected. For our bodies not only contain the genes that made us, but they also contain genes that are dormant. A well-known example of this is haemophilia. Haemophilia generally occurs only in men, but it is carried by women. A haemophiliac man cannot pass the disease on to his children, but the female can. Thus the whole problem of inheritance is overlaid with an additional layer of complication: the battle between ‘X’ (female) and ‘Y’ (male) chromosomes.

Patients are often anxious to know whether their abnormalities are inherited. While the laws of inheritance can be reduced to relatively straightforward mathematical equations, it must be understood that hereditary patterns can only be known if there is a sufficient body of data stretching back over several generations, and if there are similar histories in other families sufficient to establish general tendencies. Although the principles governing genetic determinacy are well established (they were originally identified by Gregor Mendel in the latter half of the nineteenth century), the exact function of individual genes in the chromosome is as yet only a partially explored territory, and doctors are still reliant upon what the patient or members of the patient’s family can tell him in order to decide whether or not a particular problem is or is not hereditary. There are in fact relatively few instances where a case-history stretches back long enough for a pattern of inheritance to be predictable, and these mainly concern royal or aristocratic families which have been subjected to continuous record. However, such defects as squint, shaky eyes (nystagmus), albinism and diabetes are usually present in more than one member of a family, and in more than one generation, so that there can be no doubt that they are in some way inherited. In addition, it is also found that certain abnormalities are particularly rife in isolated communities (such as remote mountain villages), which can only be explained by a combination of inheritance and interbreeding. Certain types of blindness also run in families, though, like myopia, it may be that certain environmental conditions have exploited what may only be a hereditary tendency towards blindness. Again it must be remembered that because life expectancy is much greater in the modern period, and because many abnormalities are present only in a gradually progressive form, one would not necessarily expect to discover a consistent pattern among older records. A person who was going to develop diabetes may have been killed off by cholera before he reached the appropriate age.

The greater the ophthalmologist’s knowledge of general disorders, the more help he will be in their diagnosis, or at least in making a wise referral. And this applies as much to nervous disorders as it does to diseases in the blood. The central nervous system is necessarily and intimately connected with the eye and vision, which are therefore affected by nerve and brain abnormalities. The most puzzling disorders, however, are those associated with psychosomatic and psychoneurotic conditions. While there may appear to be nothing wrong with the central nervous system, some symptoms characteristic of nervous disorders present themselves in patients who have a psychiatric history. To what extent can an abnormal personality affect the functions of otherwise normal tissues? If a doctor believes that this can happen to a significant degree, then any understanding of the signs and symptoms becomes very difficult. The ophthalmologist is also hampered by the technical limitations on measuring abnormality in the eye. He has to decide which technical means to use and, where there is a psychiatric overlay, they may very well render no positive results at all. Indeed, the tests themselves may induce introspective attitudes to the eye and vision not previously present in the patient. It can therefore become a question of when patients who continually present themselves with a symptom that seems to have no pathological basis deserve an expensive and sometimes hazardous investigation. To make a decision of this nature the experienced ophthalmologist must sometimes use non-clinical criteria in his judgment.

Tumors

Growths around the eyes, lids, tear glands and drainage apparatus, even in the eye, are very rare. Mostly they are non-malignant, and require only cosmetic treatment. In other words they can be masked by cosmetics, or just cut out. In general, once diagnosis is established, small lumps and bumps are watched, measured and photographed. Today the eye- surgeon is not likely to remove a whole eye simply on grounds of suspicion. Small cysts and pigmentary moles on the lids are watched or removed surgically. Cysts in the lid tissue itself, which press against the eye and disturb the vision, are generally removed by making an incision on the inside of the lid. The most common type is called a Meibomian cyst, or chalazion. This is a non-malignant growth or degeneration of a gland inside the lid. There are almost sixty such glands, and the removal of one of them is possibly the commonest form of eye surgery.

However, although the eye itself is little affected by malignant tumors, serious disorders in the brain, or in and about the optic nerve, will produce visual symptoms. Indeed, tumors on the brain, strokes and various forms of brain injury, can often be located by plotting an abnormality in the visual fields. In the past this was often the only way a brain surgeon had of knowing where to operate, but with modern X-ray brain-scan methods, diagnosis of brain disease by ophthalmology has become only a complementary measure.

Therefore, this exercise is a good way to measure your rental state, as well as your eyesight. When you shield tour eyes, the transition from a shimmering, gray state to leep blackness indicates the change from actively seeing o a totally relaxed, restful state.

Only the eyes can experience the sensation of blackness. The feeling produced by this darkness can be of a deep mental rest or of a pleasing sense of mental emptiness, somewhat like diving deep into your inner center, from which essential energy emanates. This can be a deeply relaxing and joyful experience. Do the shielding exercise as often as possible.

Simple Biofeedback

Shielding is a surprisingly simple form of biofeedback. This technique, widely used in research and performance sports, involves expensive instruments which change body signals into acoustic or optical signals.

You don’t need any mechanical devices in order to use shielding as a method of biofeedback, and it doesn’t cost anything. It provides an excellent way to gauge the degree of tension or relaxation at any time of the day or night.

This exercise deeply relaxes the eyes. After a phase of complete darkness and total relaxation, the vision often becomes surprisingly clear. Colors and contrasts are more lively, and the total field of vision seems clearer, somewhat like the air after a thunderstorm.

If you use shielding regularly, particularly after periods of intense work, you will discover a distinct difference in the quality of darkness when you cover your eyes with your hands.

How to Use Shielding

You can do this exercise sitting down or lying down. Assume a comfortable position where nothing will interfere with your breathing. Breathe freely in a relaxed fashion. Recommended time: one to twenty minutes.

• Rub the palms of your hands together so that they are warm and charged with energy. Warm, relaxed hands release healing, negatively-charged ions and are very invigorating. Your closed eyes will directly absorb the energy created this way.
• Close your eyes. Gently place the palms of your hands over your closed eyes. Rest your fingers on your forehead with the palms of your hands resting on your cheek bones. The palms create a small dome over the closed eyelids. Place the center of your palms over the pupils, without any pressure. Make sure that no light penetrates through your hands.
• If you are sitting down, rest your elbows on a table or on your knees. If your are lying down, place a thick pillow under your elbows. Either of these will create a very comfortable position for your hands.
• Relax your whole body. Take a few deep sighs—be vocal. Allow your eyes to sink deep behind your closed lids, as if resting in a hammock with your head hanging over t edge or into a small, soft lining behind your eye sockets like sinking into a pillow when you lie on your back.
• Be aware of what is happening beneath your close eyes in the darkness. Do you see anything shimmering, do you see lightening, fog, or patterns? Is the quality of darkness equal or is something moving? Is the darkness me intense in some places?
• Inhale and exhale deeply. Allow every thought, emotion, and image that appears in the darkness to dissolve every time you exhale.
• When inhaling, feel the warmth, the protection, and the touch of your hands through your eyelids and in your eyeballs.
• Become deeply absorbed in this process, for at least ten to twenty breaths. When exhaling, observe how the shimmering, pulling sensations; the patterns you see; and the fog enter the darkness and dissolve. When inhaling, allow the energy from your hands to flow into your eyes, filling your eye sockets like a bathtub.
• Keep your eyes closed and conclude the exercise by removing your hands from your eyes. Allow your eyes to become accustomed to light again before you open them.
• Stretch and bend as if you have just awakened from a nap. Look around. Are your eyes more relaxed and refreshed? Are they interested in what is around you? Has your sense of vision changed in any way?

Important Tips for People Who Wear Glasses or Contact Lenses

Remove your glasses or contact lenses before starting the shielding exercises.

Relax the area around your eyes before starting these exercises. Do short tapping massages with the tips of your fingers.

Afterwards, look around without your glasses or lenses. Compare your visual impressions with what they were before.

The term orthokeratology comes from the words ortho, meaning “straight,” and keratology, relating to the cornea. It should come as no surprise then that this form of vision therapy seeks to actually change the curvature of the cornea—in order to lessen the refractive error. Using much the same principle as an orthodontist employs when using braces to correct the position of wayward teeth, orthokeratology utilizes a series of relatively flat, hard PMMA contact lenses to mold the cornea gradually into the desired shape.

The process is a long and costly one. The success rate is quite low, the process may be very uncomfortable, and there are no guarantees. Even when successful the result is fleeting unless “retainer” lenses are worn periodically to prevent the elastic cornea from “bouncing back” to its natural shape. Most ophthalmologists object to this practice, citing the inadvisability of altering such a sensitive part of the anatomy (especially when so many safer alternatives are available.) There is also the possibility of permanently damaging the cornea. Nevertheless orthokeratology does have its advocates, and experimentation and research continue.

There are three methods, highly controversial and still experimental, that can correct errors of refraction:

Radial Keratotomy

This surgical procedure may be performed on those nearsighted people who cannot or do not wish to wear eyeglasses or contact lenses. The process consists of making a series of eight to sixteen radial incisions in the cornea, much like the spokes of a wheel. The incisions are about half the thickness of the cornea, and do not meet in the center, thus sparing the pupillary zone. The scored cornea flattens in shape as the incisions heal, a process that takes approximately six to eight weeks. The result is a reduction of myopia. Each patient undergoing this procedure has to be carefully selected as to degree of myopia and the thickness and condition of the cornea. Like other forms of surgery, radial keratotomy cannot be guaranteed, and complications such as scarring and perforations in the cornea can occur. The surgery can be performed as an outpatient procedure under local anesthesia. The average cost is two thousand dollars. A national investigational study is under way to determine the efficacy of radial keratotomy.

Keratophakia

Only aphakia and hyperopia can be corrected using this method, which involves the use of a human corneal donor button. The donor cornea is frozen and lathe-cut and shaped by computer technology. A portion of the recipient cornea is removed surgically and the donor button is sutured onto or placed in a center pocket of the recipient cornea. The resultant combination corrects the refractive error.

Keratomileusis

Still another experimental surgical technique utilizes a vibrating microkeratome (tiny surgical knife), which removes a 1mm-thick slice from the patient’s cornea. The slice is promptly frozen and a computer-controlled cryolathe fashions the underside of the slice to obtain the desired correction of the refractive error. After thawing out, the newly shaped corneal slice is sutured back onto the patient’s cornea. In essence the patient’s own corneal tissue has been made into a permanent contact lens.