Cut the risk of Cataract -

Free Radical Premature Eye

Very small babies must often be nursed in atmospheres of oxygen in incubators if their lives are to be preserved. Unfortunately, all eye specialists have become familiar with the devastating effects pf excessive oxygen on the eyes of these premature infants. Too much oxygen produces free radicals, and the immature tissues of the infants are especially vulnerable to their damaging effects. There is severe damage to the retina and an abnormal budding-out of fronds and tangles of new blood vessels that produce a white mass behind the lens, known as ‘retrolental fibroplasia’, which can completely obscure vision. Detachment of the retina may also occur, as may high degrees of short sight ( myopia).

These tragic results have been seen only too often in the past in very small babies who have had to be incubated. Happily, now that doctors are alive to the risk and are carefully monitoring the amount of oxygen given, severe cases are much less common. Today, the effects are usually limited to scarring and distortion of the retinas and, of course, wary widely. In one study of 572 infants of birth weight below 1,700 grams, half had visible signs of the disorder. Happily, the great majority of these cleared up without treatment. as might be expected, the lower the birth weight and the shorter the pregnancy, the greater the severity. Pediatricians often have to make agonizing decisions in which they must balance the risk to the life of the baby against the risk to its vision.

The premature eye is vulnerable because it already has a plentiful oxygen supply and an unusually high rate of oxidation. It also has a much higher than average number of mitochondria ( see p. 122 ). Newborn babies have reduced blood levels of vitamin E. this typically rises to normal within two or three weeks, but in the case of premature infants this takes much longer. Such babies therefore, have less antioxidant protection than they need.

It has, therefore, been very tempting to treat premature babies with vitamin E supplements. Here, great caution is needed. Not all free radicals are antagonistic to the body. Free radicals are the means by which certain cells of the immune system – the phagocytes – kill bacteria and viruses. It is comparatively easy in very small babies to reach very high levels of vitamin E in the blood and this may interfere with the necessary action against germs. The normal adult blood concentration of vitamin E is about 0.8 mg in every 100 cc ( 100 ml). some babies treated with vitamin E have had concentrations of as high as 5 mg per 100 cc, and an increased incidence of a serious bowel infection occurred in babies on such dosage. For this reason, although some trials have shown a significant decrease in free radical eye problems, the use of vitamin E in premature infants remains highly controversial.

What this research does indicate, however, is that vitamin E is a powerful substance that can have major effects in the body and that it should be treated with respect. People often operate on the principle that you can’t have too much of a good thing. As we have seen, this principle certainly does not apply in the context of self-treatment with some of the vitamins. There is no reason to suppose that reasonable doses of vitamin E are likely to cause any harm to children and adults. Excess of vitamins A and D can certainly be harmful ( sis p. 13). Vitamin C appears to be remarkably safe.

The evidence for the protective value of vitamins C and E against cataract is very persuasive. May be this is yet another good reason why you should consider taking them, especially if you have reached the prime of life.