Fact sheets are provided on the following subjects:

Cataracts
River Blindness
Trachoma
Vitamin A deficiency

A cataract is an opacity of the lens in the eye, which blocks light from entering the eye, thereby causing blindness.

Cataracts are the number one cause of blindness in the world, ahead of all other eye diseases.

They occur more frequently in older people than in young, and they are often linked to eye injury as well as other diseases such as glaucoma and diabetes. In cases of old age or injury, fluid collects between the lens fibres, causing them to swell and form a lump. Much like the white of an egg when heated, the clear lens becomes an opaque white.

Evidence suggests that sun exposure, smoking and severe dehydration can also contribute to the development of cataracts. Congenital cataracts can either be inherited or brought on when a mother contracts an infectious disease like measles in the first few weeks of pregnancy.

Of the estimated 45 million people in the world who are blind, approximately half are blind because of cataracts. Eighty-five percent of the world's cataract blind people live in developing countries, where the added pressures of poverty, lack of education and a lack of medical care make the blindness of cataracts an often insurmountable problem

Field hospitals in developing countries restore sight to the cataract blind by means of a relatively simple eye operation, taking only minutes and costing less than CDN $30. This unheard of cost-efficiency (in terms of the developed world) is achieved through training of specialized cataract surgeons, who then travel to rural areas, where most blind live in developing countries. Without this training component, the vast numbers of cataract blind in the developing world could never receive surgery due to the shortage of ophthalmologists. For example, in Africa, there is a ratio of one ophthalmologist to one million population; most of these ophthalmologists live in urban centres, out of reach, both physically and financially, from the rural population. In Canada, the ratio of ophthalmologists to general population is 1:28,000.

Until recently, field-hospital patients had to be provided with thick eyeglasses to perform the function of the lens removed from their eyes. Now, field surgeons are beginning to place low-cost intraocular lens implants right inside the eye. With this technology, which has been available in the western world for some time, patients enjoy better vision without having to worry about maintaining or replacing eyeglasses.

"River blindness" is the common name for onchocerciasis, a disease caused by the parasitic "oncho" worm. This worm is transmitted by black flies that breed along fast flowing rivers. When an infected black fly bites a human being, it implants an oncho worm just beneath the skin's surface. There the oncho worm thrives and breeds. The baby worms, or "microfilaria" migrate throughout the body and up into the eye region, and as they begin to die off, they cause the body to react with itching, skin rashes and red, watery eyes. Eventually and inevitably, the microfilaria destroy the optic nerve and cause irreversible blindness.

The disease is rampant in countries throughout West and Central Africa and in a few regions of Latin America (a total of 37 countries). An estimated 17 million people are infected with onchocerciasis — most over 25 — with 500,000 gone blind already. MectizanÔ , a donated tablet from international pharmaceutical company Merck, can treat the infection and prevent blindness if taken once every year.

In addition to the half a million people directly affected by losing their sight to this disease, their families have suffered the repercussions of having a parent or grandparent blinded by it. Children who depend upon these family members for food and shelter can no longer be adequately cared for. The impoverishing effects of river blindness reach into entire communities — as people are driven from their homes and their lands for fear of going blind, large tracts of fertile riverside land are rendered unusable. The economic impact on communities and nations already struggling to feed and care for destitute populations is staggering.

Fortunately, the MectizanÔ  treatment is very effective. To break the cycle of infection, the medication must be taken once per year for 10 years. Although the MectizanÔ itself is donated free of charge, the long-term distribution of such a drug to millions of people is an enormous task. It costs an average of 50 cents per person to administer the medication.

Field workers must often improvise in such distribution programs. To ensure the correct MectizanÔ  dosage, workers traditionally carried scales with them from village to village. Each person was weighed before receiving the appropriate dose of medication (anywhere from half a tablet to two tablets). Recognizing the extra time and resources this approach required, field worker Jeff Watson, based in Nigeria, developed an adequate correlation between weight and height. He designed easy-to-use, easy-to-carry height measurement sticks for the workers in his program. Using this approach, his program administers sight-saving MectizanÔ  to roughly 1.5 million people per year at risk of river blindness.

Trachoma is an infectious disease of the eye caused by the microorganism chlamydia trachomatis. It is one of the leading causes of blindness in the world today, especially in dry, poverty-stricken areas of the world where water is scarce and washing is difficult. A general lack of hygiene, smoke from cooking fires and blowing dust provide a perfect environment for the microorganism to take hold, infecting and re-infecting eyes throughout a community. The condition is worsened by overcrowding, where children sleep packed together and flies swarm around exposed refuse.

After years of repeated infection, as children pass the trachoma organism back and forth and flies carry it from face to face, scarring gradually builds up on the underside of the eyelid. The infection becomes more painful and damaging in adulthood, as the scarring causes the eyelid to turn inward, pulling the eyelashes into contact with the cornea (a condition known as trichiasis). The eyelashes break off into bristles that scratch the cornea, causing pain, opaque scarring and ultimately irreversible blindness.

Six million people in the world have already been irreversibly blinded by trachoma. Three-quarters of these are women, who are at greater risk due to their constant contact with children, the prime carriers of the trachoma infection. An additional 146 million people, 75 per cent of them children, have the active disease and are in need of treatment. In communities where trachoma is common, infections start in early childhood. Inflammation from repeated trachoma infection becomes intense in preschool and school-age children up to six to eight years of age.

In the early stages of trachoma infection antibiotics are effective. Tetracycline eye ointment, or azithromycin tablets, get rid of the infection. However, if a child is exposed to siblings or friends with trachoma, he or she can be re-infected in just a few months. For this reason, it is more effective to treat a whole family than to treat an individual child. And it is even more effective to treat an entire village. For CDN $5, an average family can be treated with tetracycline eye ointment. Eighty dollars will provide enough tetracycline for all the children in a typical African village of 1,000 people.

In its advanced stages, surgery is necessary to rotate the eyelid back to its original position to prevent further laceration of the cornea. Since this is a relatively simple operation, nurses and medical assistants can be trained to perform it at local dispensaries or clinics, at a cost of just $25. At least 10.5 million adults in the world are in urgent need of this surgery.

Common in Europe 150 years ago, trachoma is essentially a disease of the poor, particularly of women and children. Under the leadership of the World Health Organization, a coordinated approach is being taken in the hopes of eventually eradicating the disease. The four elements of the "SAFE" program are:

S – Surgery against turned-in eyelashes;
A – Antibiotics that fight against the disease,
F – Face cleanliness to stop the spread of the disease; and
E – Environmental improvement, meaning better water and sanitation.

Face cleansing, especially for children, is one of the best ways to prevent the trachoma infection from starting in the first place. Yet, in many ways, it is the most difficult to implement. In the dry regions of Africa, Asia and Latin America, where water is in low supply, face washing is not simply a matter of turning on the tap. It is an issue of time, a woman's time, and her perceived priorities.

Field workers educate mothers so they understand the necessity of spending the many hours it will take to retrieve well water for washing her children's faces, when drought and poverty make even feeding them a trial. At the same time, practical advice is provided as to how to minimize the amount of water required. For example, by using an empty tin or a hollowed out gourd with a small hole punched in the bottom, several children's faces can be washed with just one cup of water. Where resources permit, field workers also encourage husbands, older siblings and primary schools to join the cause of face cleansing.

Environmental improvement, both at the household and at the community levels, is essential in the fight against trachoma. At the household level this means teaching families to build latrines, collect rain water, carefully dispose of rubbish and ventilate sleeping areas. At the community level it means improving the water supply, the village sanitation, the housing, and encouraging adult education.

If such environmental improvement is to be achieved, villages need to be motivated and empowered to cooperate with government agencies, other missions and non-governmental organizations, local hospitals and services.

Vitamin A deficiency and malnutrition is the number one cause of blindness among children throughout the developing world. It is responsible for irreversibly blinding an estimated 350,000 children and killing two million children each year. Two hundred and fifty million pre-school children in the world are currently vitamin A deficient.

More than 1.5 million children in the world are blind ¾ of these, more than 50 per cent are irreversibly blind because of vitamin A deficiency. More than half of the children who go blind die within two years of losing their sight.

Vitamin A is necessary for all of our body's tissues: our lungs, our mucous membranes, our eyes. It is especially important for the developing eyes of children aged six and under. The body usually has enough vitamin A in the liver to last for about six months. And fortunately for most of us ¾ particularly those of us in the developed world ¾ we get all the vitamin A we need through our regular diet.

But in developing countries ¾ many ravaged by famine and drought ¾ vitamin-A-rich foods, such as fruits and green vegetables, liver and milk, are not always available. Even in regions where these are available, young children are not always fed vitamin-A-rich foods because of traditional and religious customs that dictate that these should not be eaten, or are inappropriate for children under a certain age.

When young vitamin-deficient children then contract diseases that further reduce their intake of vitamin A (diarrhea) or diseases that use up a large amount of vitamin A (measles), their vitamin A supplies drop to dangerous levels. Such clinical cases of vitamin A deficiency, left untreated, cause irreparable damage to the cornea, and will almost always lead to blindness and, far too often, to death.

For those children whose supply of vitamin A is critically low, as well as for those children who have contracted measles or severe diarrhea, capsules containing high concentrations of vitamin A (200,000 IU) can stop the blinding effects of vitamin A deficiency in their tracks. Three vitamin A capsules, at a cost of 60 cents including distribution, can save a child's sight and very often his or her life.

A second weapon against blinding vitamin A deficiency is measles immunization, which greatly reduces the likelihood that children will contract this vitamin-A-deficiency aggravating illness.

The most important weapon against vitamin A deficiency is education. Mothers and fathers need to be taught the importance of feeding their young children vitamin-A-rich foods. And, when necessary, they need to be taught how to grow these foods. As an example, some development projects distribute papaya tree seeds to families so they can grow their own vitamin-rich papayas.