Cataract

Throughout the world 19 million people have gone blind because of cataracts. It is the most frequent cause of blindness in developing countries. About 100 million people have a visual impairment because of cataract.

What is cataract?

About 1% of all cataracts are congenital. For instance, this can occur due to a severe infection in the early stages of pregnancy such as measles, mumps or an infection such as hepatitis or toxoplasmosis. Cataracts can also be inherited.
The most frequent form of cataract is lens clouding as a result of ageing. In the underprivileged regions of the world injuries and inflammations are also frequent causes and similarly metabolic diseases such as diabetes.

Mild to severe clouding of the lens marks the beginning of the disease. Everything appears grey as if you were looking through frosted glass. The cloudiness does not always affect the entire range of vision. The patient may have distorted, double or treble vision. Sight is often better in twilight than in sunlight.

If the cataract is not treated, later it is no longer possible to clearly define it. Visual acuity is reduced to light-dark impression; at best hand movements can be perceived in front of the eye. If the patient has cataracts in both eyes then he or she is practically blind and dependent on the help of others in day-to-day life.

Treatment

Surgeries to remove cataract are by far the most frequent method in curing eye diseases.

Before the surgery, eye pressure is elevated

The operation is carried out under a local anaesthetic, i.e. only the eye is anaesthetised. Normally the surgeon uses an operation microscope, formerly magnifying glasses were used and in areas where operations are not carried out so frequently the latter are still in use for financial reasons.

The old clouded lens is removed

During the operation the clouded lens is removed and exchanged for an artificial, intra-ocular lens. The implantation a lens has to be carried out by a surgeon used to doing the operation; cataract surgeons are being trained in this method.

Prior to the operation a biometric analysis will be carried out. The necessary refraction index of the artificial lens is precisely calculated before the operation. High refraction anomalies can be compensated by a well adapted artificial lens. After the operation the person's vision is almost perfect.

The artificial, intra-ocular lens is put in

In "Third World" countries it is often not possible to carry out a biometric analysis, as a special equipment is required. Standard lenses are used which are of good quality and the costs are not too high (rear chamber lenses with a strength of 20 or 21 dioptres). After the operation the patient can see again, even though not 100% in all cases.

In many parts of Africa there are not enough eye specialists to carry out the number of cataract operations that would be needed (on average there is only 1 eye specialist per 1 million inhabitants, indeed in some areas only 1 eye specialist for 4-10 million inhabitants). This is why eye- assistants are trained in diagnosing and treating eye patients. Particularly talented eyeassistants and -nurses receive additional training so that they can operate on blind patients with bilateral, advanced and age-related cataracts (Cataract surgeon). Training lasts about one year.

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Xerophthalmia - blindness due to a deficiency in vitamin A

Bitot-spots in the eye are the first visible sign for vitamin A deficiency.

About 250 million people worldwide suffer from a deficiency in vitamin A (this includes all stages from light to a dangerously high deficiency). About 2 million children die annually because of this deficiency. 6-7 million children have clinical signs of vitamin A deficiency and are at a greater risk.
Xerophthalmia (blindness due to a deficiency in vitamin A) occurs primarily in South-East Asia and in the central regions of Africa. Today it is the cause for 30% of children going blind.

What happens in the eye when there is a deficiency in vitamin A?

Initially white spots can be seen in the eye. These occur because of a build-up of crusted material on the exterior of the conjunctiva. These spots are the first visible signs of an acute vitamin A deficiency (deficiency indicator). At this stage the ability to see is already limited by night blindness and cloudy vision.

This child arrived too late at the eye clinic in Yirgalem, Ethiopia. He lost his sight because of vitamin a deficiency

Then the cornea dries out because of the lacking tear fluid. Up to this point the damage is still curable by an immediate intake of vitamin A. However, if ulcers form, irreversible damage occurs. In the final stage the cornea is dissolved within a few days and is replaced by scarred tissue. The eyes are incurably blinded.

Malnourished children frequently suffer from diarrhoea or measles and their condition can deteriorate drastically within a short time. A malnourished child suffering from measles can be incurably blinded within 48 hours.
As the immune system is also weakened about 70% of children suffering from a vitamin A deficiency die within 2 years.

Why does xerophthalmia occur?

The reason for xerophthalmia is malnutrition. People living in secluded parts of a country often do not know that vitamins and nutrients are contained in plants growing naturally. People mostly eat loaves of maize or another kind of cereal.

That is the cheapest food and satisfies their hunger for quite a long time but it hardly contains any nutrients and no vitamins. Fruits containing vitamin A are generally very expensive. If fruits are cultivated they are sold on the market. Sometimes incorrect storage can also lead to vitamin A being destroyed because of oxidationand heat during preparation.

Furthermore, most people have no possibility of visiting an eye specialist when the first symptoms such as night blindness occur. When parents do take on the burden of finding treatment (which involves a long journey at high costs) it is often too late to save the child's eyesight.

By giving vitamin a to Tachawt, Ethiopia, her eyesight was saved.

Treatment

In the case of acute deficiency children are given three high doses of vitamin A on two consecutive days and then again within a month. In the case of latent malnutrition in the following years high doses of vitamin A is administered every 3 to 6 months; children aged between 1 and 6 years are given a capsule containing 200 000 IU (international units) corresponding to the dosage recommended by the WHO.

LIGHT FOR THE WORLD - Christoffel Development Cooperation organises the distribution of capsules (the costs for one child for one year amount to EUR 1,00), which the company Roche provides free of charge.

As a preventive measure children are examined in schools and they receive vitamin A medication. They are also immunised against risk factors such as measles. The parents are informed which vitamin A containing plants do not cost too much. They are also shown how the plants should be stored properly and also how to prepare meals correctly so that vitamin A is not destroyed.

Plants that contain vitamin A and grow in the southern hemisphere are: sweet potatoes, red palm oil, pumpkins for human consumption, kaki, mango, papaya, passion fruit, cashew nuts, chilli, dark green leaf vegetables.

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Trachoma

In the 19th and early 20th century this disease also occurred frequently in the northern hemisphere. Trachoma always occurs in connection with poverty, drought and a lack of hygiene and nowadays is to be found in the underprivileged regions of the world, the so-called "Third World". Trachoma occurs mainly in Africa, in the Middle East, in South-East Asia and Central Australia.

About 150 million people suffer from a trachoma infection. Thanks to combined efforts in the fight against trachoma the number of infected persons has been reduced from 500 million to 150 million in the past 20 years. However, 6 million people have already gone blind and can no longer be cured.
Still 10-15% of blind people worldwide lose their sight because of trachoma.

What is trachoma?

Trachoma is an inflammation of the eyelid (tarsus) caused by an infection with chlamydia trachomatis, serotypes A, B and C. The bacterium is gram-negative. The illness occurs especially in dry regions of the world, where there is hardly any safe water available and hygienic conditions are deficient.

The illness is transferred from child to child, from mother to child or by flies who wander from person to person in search of secretions in the eyes and nose. However, the hands and clothing can also come into frequent direct contact with the eye secretion. (For example, the mother wipes the eyes of her infected child with her scarf. She then touches the eyes of her other children with the same scarf).

Within families and village communities the bacteria are constantly transferred and so there is permanent danger of re-infection. This makes trachoma a real problem. If a child were only to be infected once, its body could deal with the inflammation itself.

When a person has been infected with trachoma, the eye itches and is painful because of the inflammation. A secretion is formed, in later stages of the disease the inflammation leads to the eyelid turning inwards and the eyelashes scratch the cornea. This is thereby irritated and results in keratitis, a damaged cornea. Eyesight is increasingly impaired.

The WHO makes a distinction between 4 stages of the illness according to the clinical symptoms:

On the inside of the upper eyelid, follicles started to grow.

• Stage I
  Five or more follicles (raised blisters) form on the inside of the upper eyelid (tarsus superior). The eye waters and itches, a secretion is formed around the eyelids. An antibiotic eye ointment has to be applied.
• Stage II
  At least 50% of the lower tarsus vessels are covered by inflamed tissue both on the upper and lower eyelid. Here too an antibiotic ointment can help.
• Stage III
  White scars in the connective tissue are evident on the interior of the eyelid (tarsus). By this stage the eyelid turns inwards. It is necessary to operate on the eyelid otherwise the disease progresses to stage IV.
• Stage IV
  At least one eyelash is turned inwards and touches the eyeball; the cornea is cloudy to such an extent that at least one part of the edge of the pupil is covered.

Treatment

The so-called SAFE strategy encompasses the following measures for treating trachoma: Surgery - Antibiotics - Face Washing - Environment)
In the early stage an antibiotic eye ointment is used to treat the disease, 2-3 times a day over a period of six weeks. This reduces the extent of the inflammation. It is of great importance that patients change their behaviour and pay due attention to hygiene otherwise a re-infection can occur repeatedly. The relatively long period of treatment, six weeks, can also lead to problems as insufficient checks can be made whether the treatment is being carried out as prescribed. It is therefore all the more important to create an awareness of the problem especially among the mothers.

Surgery on trachoma at an outreach-programme in Ethiopia

In the late stage the only option is an operation. If the eyelid is already turned inwards (entropium) and the eyelashes are scratching the cornea, some incisions are made and then some stitches so that the eyelid is turned outwards and secured in such a way that the eyelashes no longer scratch the cornea. As this is not an operation on the eye itself, it can be carried out by eye nurses and specially trained eye assistants. Operations are carried out directly as part of Outreach Programmes in the villages. If the cornea has already been damaged, impaired vision and the resultant blindness can no longer be prevented.

The most important and sustainable means of fighting trachoma are information and sensitisation campaigns. By adopting the right behaviour it is easier to protect oneself against infection. Therefore it is the aim of the eye assistants to create on the one hand awareness of how necessary it is to wash the eyes regularly (with only little water) and on the other to improve hygienic conditions in the surroundings (by providing safe water and latrines).

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River blindness

The black fly is transmittor of onchozercosis.

At present about 17 million people suffer from river blindness. 270,000 have gone blind and in the case of another 500,000 their vision is already strongly impaired.

River blindness or onchozercosis is a major health and social problem in tropical regions. In former times the majority of inhabitants living near to rivers used to go blind. As they were afraid of going blind people moved away from the fertile regions to dry areas. There they faced other problems, in particular drought.

Under the microscope, the mikrofilaria are visible.

What is river blindness?

River blindness (onchozercosis) is a parasitic retinal disease. It is caused by the onchocerca volvulus, a threadworm. The larvae of this worm are transmitted by bites of the mosquito of the genre simulium, also known as the "Black Mosquito". They live beside fast-flowing rivers.

The makrofilaria live in encapsulated knots under the skin.

After the mosquito has bitten a person the microscopically small larvae of the threadworm penetrate the connective tissue of the sub-skin. Within 12 months they mature and become fully grown worms and live as parasites. The females live together with several males about four centimetres long in large encapsulated knots which can mostly be felt. They constantly produce new larvae.

In the knot in the man's forehead the worms encapsulate.

These larvae, also known as micro-filaria, wander through the connective tissue of the sub-skin and thereby penetrate the blood circulation often as far as the eyes. The immune system produces hefty reactions that can produce a tortuous itching throughout the entire body. If the eyes are affected, the cornea becomes inflamed. After a while it becomes clouded and finally the patient goes blind. The sight nerve can also be affected and consequently destroyed which results in total loss of sight.

Treatment

Treatment with Mectizan.

The most common method of treatment is with Mectizan (containing Ivermectin) that has been successfully applied for many years.

Ivermectin kills the larvae/micro-filaria. The adult worms can live for a further 12 years and constantly produce new larvae. It is necessary therefore that the medication is taken consistently over long periods (once to twice a year and in doses calculated in relation to body weight). It prevents the micro-filaria from living long enough to penetrate the eye and thereby cause blindness.

Mectizan is at present being provided for the current programmes by the pharmaceutical concern Merck free of charge. LIGHT FOR THE WORLD - Christoffel Development Cooperation takes care of distribution; the costs are about 1 Euro for each tablet distributed.

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