When examining you an ophthalmologist will test eye-pressure through the simple expedient of placing his fingers on your closed eyelids. The experienced physician will know immediately whether the pressure is unusually high, but even so he is unlikely to be able to distinguish, using this technique, between more than four grades: namely soft, normal, suspicious and high. Accurate measurement requires instruments. Such instruments have to touch the cornea, which is therefore suitably anaesthetized beforehand, using a special kind of drop. Several types of local anaesthetic drop exist, e.g. amethocaine, pentocaine and xylocaine. One instrument blows a puff of air on to the cornea and then measures the degree of corneal flattening that results. This does not require a local anaesthetic. Read the rest of this entry »
Where cataract is due to abnormal body metabolism, then treatment of the metabolic disorder can sometimes prevent development of cataract, or even reverse cataract where cataract has begun. Diabetes mellitus is a good example of this. Otherwise metabolic cataract can be treated by conventional methods. It should be said at once that in most countries of the world eye-drops and medicines of ill-founded clinical value, and rarely backed by any sound medical trials, are still available. Read the rest of this entry »
Basically, good and bad characteristics, healthy and unhealthy trends, are divided into dominant and recessive. Those that are dominant are handed down and show in the offspring; those that are recessive are handed down but do not show. Further, dominance and recession are often linked to the sex of the individual. Thus we talk about traits that are ‘dominant in females’, ‘dominant in males’, ‘recessive in females’, and ‘recessive in males’.
Suppose, for example, that both parents had a recessive trait `A’. If they had nine children the chances are that only three of them would be marked by ‘A’. But if they had only two children, the chances of either of their offspring showing trait ‘A’ are small indeed, whether the trait is for weak legs or musical genius. But if both parents had dominants of a certain trait, this would almost certainly come out in the offspring. Read the rest of this entry »
