Eye Care Blog

Central Nervous System

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. Read the rest of this entry »

The retina, or rear receptor part of the eye, consists of a layer of different kinds of cell which meet the demands of different kinds of sight: detail and outline, colour, light and dark. But these cells cannot work unless they can produce the chemicals used to react with light energy, and the chemicals that are used to transmit the light-nervous energy to the brain. These chemicals and their application are a vastly complex subject which is still being explored; but it is known that all the products needed for retinal function come, in the last analysis, from the blood supply. Read the rest of this entry »

At the beginning of this century the most prominent cause of blindness was infections of the eye. The eye is exposed externally to infections because of the very delicate skin-lining of the lids and sensitive outer membrane of the eye itself. Other tissue areas of equal susceptibility to infection are the nose, mouth and genitalia. It is even possible for all these orifices to be infected by the same organism.

Since the the availability of antibiotics has drastically reduced the incidence of chronic consequences following an infection. Many serious infections, provided they are treated quickly, no longer inflict severe damage. Read the rest of this entry »

Contusions

Severe blows to the face and eyes are relatively rare in life; but casual blows and knocks are common, occurring mostly in the home or on the sports field. For those involved in warfare they are common enough injuries. Explosions exert great changes of air pressure upon the body, followed by a rebound as the pressure suddenly drops again. This is the invisible fist of the battlefield, and of some industrial accidents. The eye can be convulsed from its muscle connections and the orbit severely damaged. Most explosions are also associated with flying debris (it could be shrapnel, it could be glass), so that injury is often compounded by different types of damage. Other instances where contusive damage occurs are motor accidents, especially where safety belts are not worn, champagne bottle corks, squash balls and fireworks. Read the rest of this entry »

More familiar to us are X-rays, harmful to our tissues in large doses. They can cause cataract and retinal damage. In practice X-rays used for diagnostic purposes are of low dosage, and their effects, both as regards the patient and the practitioner, are controlled. In high intensity they can be used in narrow beams to burn away tissue. (Laser is an example of concentrated light rays.) If such beams are directed on the eye, immediate and irreparable damage would be done. The eye is designed to cope with normal light, i.e. that part of the light (electro-magnetic radiation) between the infra-red and ultra-violet parts of the spectrum. The spectrum extends considerably further in each direction, and the eye can only absorb small low-dosage radiations from these outer areas. In outer space such radiations abound, but the earth’s atmosphere acts as a screen protecting us from harmful rays. Read the rest of this entry »

The eye has its natural protective mechanisms. The lids, for example, protect the front of the eye from dust, wind and objects coming towards the face. They also protect the eye from excessive light. The eye itself is set in its bony cavity: the orbit. In the orbit there are some soft fatty tissues which act as a cushion, permitting the eye to sustain a light blow without injury. Nevertheless the eyes are vulnerable. The eye will be injured, often severely, by fast-flying hard objects, and also by some gases and solutions. It is easy to incapacitate a human being, either temporarily or permanently, by spraying irritant solutions onto the face, and such methods have been widely used by criminals, police and the armed services. Read the rest of this entry »

Adults who become blind after several decades of normal or at least useful sight represent a different problem. Their psychological and practical difficulties are manifold. The sudden onset of blindness is a terrifying experience. Apart from the helplessness and inability to become mobile there is a horror of incapacity, accompanied by the realization that without help the sufferer is completely isolated, socially and physically. The adult who becomes blind is liable to become deeply embittered, much more so than if he or she had lost a limb. The loss of a limb is measurable and understandable. Sudden blindness is far more abstract, for a while incomprehensible. And because the loss of sight is rarely complete, the patient lives in hope of cure. Bouts of depression alternate with pitiable optimism. If the patient is rich, or if the public health authority permits, he or she will seek charlatan as well as professional advice. He or she will become subject to advice from the market place, faith healers and the like. Newly blind people will sometimes travel grêat distances to seek remission. If religious they will seek shrines and miracles (and some people become religious when they become blind). Equally they will alter their philosophy of life, to purge that which is supposed to have robbed them of their sight. Read the rest of this entry »

There is a well-known story about Noel Coward. The dramatist was out walking with two small children one day when the party came into view of two dogs engaged in the act of copulation. `Uncle Noel, what are they doing?’ cried one of the boys. ‘It’s perfectly obvious,’ replied Coward. ‘Can’t you see? The dog in front is blind, and the dog behind is pushing him to St Dunstan’s!’

The subtlety of this anecdote lies in the substitution of one taboo subject by another. Historically, blindness has carried different cultural connotations. Among the ancients it was often considered as a punishment meted out by the gods. In the best known of the Greek myths, Oedipus gouges out his own eyes in a hubristic act of self-inflicted retribution. In modern times blindness is more simply perceived as a misfortune. Read the rest of this entry »

A very common phenomenon of imperfect eye sight is that one, already mentioned, which is known as muscae volitantes, or flying flies. These eye floating specks are usually dark or black, but sometimes appear as white bubbles, and in rare cases may assume all the colors of the rainbow. They move somewhat rapidly, usually in curving lines, before the eyes, and always appear to be just beyond the point of fixation. If one tries to look at them directly, they seem to move a little farther away. Hence their name. Read the rest of this entry »

In another case that came to my attention, a man returning from Europe was looking at some white clouds one day when eye floating specks appeared before his eyes. He consulted the ship’s doctor, who told him that the symptom was very serious and might be the forerunner of blindness. It might also indicate incipient insanity, as well as other nervous or organic diseases. He was advised to consult his family physician and an eye specialist as soon as he landed, which he did. Read the rest of this entry »