Introduction1

The eye is a truly amazing structure. Rays of light from the outside world enter the eye and are converted into electrical impulses that are transferred along visual pathways to the brain, which uses this information to generate a picture of the world – to allow us to see. The eyes provide about half the total sensory input from the entire body into the brain. There is, however, one small defect in the visual image produced by the healthy eye: the ‘blind spot’. This is a small area in our field of vision where we are unable to see. It corresponds to where the optic nerve leaves the eye. Remarkably, our brain creates appropriate images to fill in the blind spot, so that we are not even aware of it. Unfortunately there is a very large ‘blind-spot’ in worldwide ophthalmology. This is the tragedy of avoidable blindness in poor countries. Approximately 285 million people worldwide are visually impaired. About three quarters of this is treatable or avoidable. And just as in the eye, we cover over this blind spot and ignore it. Medical science, governments and health care workers largely neglect the millions of blind and visually impaired people worldwide. Indeed, that is the only reason why they are blind.

The diseases of hot climates have traditionally been called ‘tropical’ diseases, although some hot countries are not exactly in the tropics, which is the 2region of the earth surrounding the equator. There are two important features about these areas with hotter climates. Firstly, some diseases may be influenced directly by the heat, humidity and solar radiation. For example, this climate encourages the growth and multiplication of bacteria, fungi and other micro-organisms that cause corneal infections and the insects and other carriers that cause many infective diseases. Secondly, and more importantly, a look at the world map will show that most hot countries are also poor (Figure 1.1). Poverty is associated with poor hygiene, poor nutrition, poor provision of and access to healthcare, civil wars and poor management of natural disasters, all of which are devastating for healthcare.

In the last few decades, countries with poor economies have been referred to in several ways, such as the Third World, developing countries, resource poor countries/settings, low income countries/settings. Each of these terms has problems.

We are therefore left doing a full circle back to the only phrase that accurately and honestly describes the economic situation in many areas: poor countries. We will therefore use this term throughout the book, although it must be emphasised that we are referring to the economic definition of the word ‘poor’ and it is not a reflection on other qualities in the many wonderful poor countries of the world. Also, these countries are often very rich in the culture and the resourcefulness of the people to overcome the difficulties and problems that are thrust on them.

Some diseases, such as trachoma and xerophthalmia (vitamin A deficiency associated eye disease) are seen more frequently because they are caused or worsened by poverty, the heat or the endemic micro-organisms and vectors. Other diseases, such as cataract and glaucoma, are the same as those seen in rich countries, but are seen at a much more advanced stage because of the lack of access to healthcare. Sometimes, e.g. cataract, the disease can still be treated, but other times, e.g. glaucoma, the visual loss is irreversible. Finally, some diseases, such as age-related macular degeneration and retinopathy of prematurity are seen less frequently in poor countries, because the life expectancy of adults is shorter and very premature babies are unlikely to survive.

The World Health Organization (WHO) defines blindness as ‘visual acuity less than 3/60 in the better eye with the best possible spectacle correction or a corresponding visual field loss’. This degree of visual loss prevents the patient from walking about or navigating independently. In addition, the WHO has another category called ‘low vision’. Low vision corresponds to a visual acuity of less than 6/18, but equal to or better than 3/60 in the better eye with the best possible spectacle correction. Such people have a significant visual impairment which often makes working difficult, but they can get around independently.

The most recent estimates are that worldwide 246 million people are visually impaired and 39 million blind. About 90% of them live in poor countries, 80% of it is avoidable and 60% are women. In fact, the proportion of women may be greater because women often have less opportunity to seek healthcare and be ‘counted’. The prevalence figures for visual loss are very approximate estimates, as counting the number of blind and visually impaired people is extremely difficult for the following reasons:

The number of blind people in each region are shown in Table 1.2. Although the actual numbers of blind and visually impaired people are highest in Asia, this is because these are the most populous areas of the world. The highest prevalence of blind people are in some countries of sub-Saharan Africa (Niger, Mauritania, Mali, Chad, Somalia, Ethiopia and Burkina Faso).

Over two thirds of worldwide visual impairment and blindness could be eliminated if the necessary treatment was provided for just refractive error and cataract. The major causes of preventable disease are listed in Box 1.1. There are also some causes of blindness that can neither be prevented nor treated. However, these are much less common in poor countries, either because they are rare, such as congenital abnormalities in children or because in many countries the life expectancy is not long enough for most people to develop these diseases such as degenerative and vascular diseases of the retina. Therefore, these diseases make up a much larger proportion of visual impairment in rich countries, where almost all people with refractive error are able to get glasses, those with cataract get cataract surgery before they are significantly impaired, glaucoma gets detected and treated early, and trachoma and onchocerciasis do not exist (Figure 1.2).

Eye diseases are a major health problem in most of the tropics and, in some places, may be the biggest community health problem of all. Yet there are not nearly enough trained medical staff to tackle this large and challenging problem. It has been said that there are more ophthalmologists in New York than in all of sub-Saharan Africa. In most African countries and in many rural areas of Asia there is less than one trained eye specialist for a million or more people compared to 81 per million in America.

In some countries, there may be almost an excess of specialists in the capital cities, and competition for work, but hardly any specialists in the rural areas. Furthermore eye care 8programmes have to compete with more serious life-threatening diseases for the small amount of money in health care budgets.

There have been many large and small scale plans and strategies for addressing eye disease and visual impairment in poor countries. We will discuss the two major recent International Plans – VISION 2020 and Universal Eye Health – as well as a smaller and less prominent but potentially very effective strategy – institutional links between eye units in poor and rich countries.

In 1999 the World Health Organisation (WHO) and the International Agency for the Prevention of Blindness (IAPB) launched a plan called ‘VISION 2020 The Right to Sight’. IAPB is a coalition of many organisations involved in eye care, such as non-governmental organisations, eye care institutions and corporations, all of which are therefore involved in VISION 2020. The aim of VISION 2020 is to eliminate avoidable blindness, as a public health problem, by the year 2020 (as well as being the year 2020, it is also a reference to the assessment of vision, in feet rather than metres; 20/20 which is the same as 6/6 in metres, is ‘normal’ vision). The philosophy of VISION 2020 is that all people have the right to a basic level of healthcare, and this includes the right to sight and not to lose vision from treatable diseases. Therefore, the ultimate goal is that everyone has access to high-quality eye care that is part of a sustainable health system. VISION 2020 hopes to achieve this by providing guidance, support and advocacy for eye care. A summary of the original 1999 action plan is shown in Box 1.2 and described in more detail in the following pages.9

The VISION 2020 plan was updated in 2006. This plan was based on the same three core principles in Box 1.2, but highlighted the importance of the following ideas:

As we get closer to the year 2020, it is clear that the ambitious target of eliminating all avoidable blindness by 2020 will not be met. Worldwide, there are now thought to be 39 million blind people and 246 with low vision. In 1999, the estimated figures were 38 million blind and 110 million with low vision. There are probably several reasons for this apparent increase:

Has VISION 2020 failed? The answer is of course a resounding ‘no’, as VISION 2020 has been responsible for raising the profile of visual loss, for treating many millions of people and for raising money for eye care and eye research. However, the original target of eliminating avoidable blindness by 2020 will not be achieved and there is still an enormous amount to be done.

One of the possible shortcomings of the original VISION 2020 plan was its emphasis on eliminating certain specific diseases. A strategy that focuses on particular diseases is sometimes called a ‘vertical’ plan. In recent years, there has been increased emphasis on seeing eye care as part of general health care services. This is sometimes called a ‘horizontal’ health plan because it covers all aspects of health care.

However, in the end, a ‘plan’ is only as good as the commitment and determination of us the eye care workers to put it into action.

‘Links’ refers to partnerships between an eye department in a poor country and one in a rich country. Health institutions in rich countries should not think about just their own population's needs and there are numerous reasons for being involved in the health needs of poor countries. ‘Links’ are an excellent way of joining the respective health systems and should be seen as an obligation rather than a luxury for the following reasons:

The VISION 2020 LINKS programme is a UK programme that is designed to support the aims of Vision 2020 by setting up institution-to-institution partnerships, mainly in Africa. The programme is already seeing huge benefits to institutions and the people who work in them on both sides of the partnership. Informed partnerships have been established elsewhere in the world, but it hoped that other countries in the world will also set up more formalised partnerships.

The major worldwide causes of blindness can be divided into four groups:

VISION 2020 is targeting the first two groups, although the increase in the ageing population has brought about greatly increased focus on the eye diseases of older people, some of which are untreatable. VISION 2020 has also made it a priority to target childhood blindness, because although often more difficult to prevent or treat, it has an enormous impact on the rest of the child's life and the community they live in.

This group consists of three diseases which are almost exclusively found in poor countries and particularly, poor countries with hot climates. These diseases are: trachoma, xerophthalmia (vitamin A deficiency associated eye disease) and onchocerciasis. They are all easily preventable, but once blindness has occurred, treatment or restoration of vision is difficult or impossible. Onchocerciasis occurs in just a few areas. Trachoma and xerophthalmia are more widespread in poor countries, although with great variation in prevalence. In the places where they are more prevalent, they can be major causes of blindness. Blinding trachoma can be prevented by improvements in hygiene and living conditions, and blinding xerophthalmia can be prevented by improvements in nutrition.

Cataract and refractive error are found throughout the world. However, both of these conditions rarely cause severe visual impairment or blindness in rich countries but are by far the commonest causes of visual loss in poor countries where poor medical services simply cannot address the huge number of cases.

People with serious refractive errors need spectacles to see properly. Uncorrected refractive errors are a significant cause of visual impairment, and even ‘blindness’, in places where it is difficult to obtain spectacles. Refractive errors are particularly important because they usually develop in young children, and will therefore affect the education and development and therefore the entire future life of the child.

Cataracts are quickly and relatively cheaply eliminated with a surgical procedure. This procedure only needs to be done once for each patient. The results can be fantastic, but complications can also occur and the patient left with worse vision than before the operation. However, ‘new’ cataracts are continually developing in patients. This is illustrated in Figure 1.3. If more surgical procedures are being done than new cataracts developing, the number of people blind from cataracts will fall. But if more cataracts are developing than surgeries being conducted, the number of blind people will rise. The ‘cataract surgical rate’ (CSR) is the number of cataract surgeries performed per million people in the population. The CSR helps us to determine if the number of cataract surgeries being done is enough to keep up with new cataracts developing. For example, we know that when the CSR in rich countries was about 3500, surgical output kept up with new cases. However, there are issues that must be considered when targeting a particular CSR for a particular country:

As a result of these problems with the provision of cataract surgery, the prevalence of visually impaired people with cataract has remained fairly static, unlike the other WHO priority diseases, trachoma, xerophthalmia and onchocerciasis which have shown dramatic improvements in recent years.

Many African countries have 1 or less ophthalmologists per million people in the population. In these countries, it is entirely appropriate to train people who are not doctors to do cataract surgery, because otherwise many millions of people will continue to be needlessly blind. A good example of this is the Gambia, a small country in West Africa where the training of cataract 15surgeons who are not doctors is actively encouraged. The Gambia is also the only country in West Africa which is beginning to meet its target of eradicating cataract blindness. The surgical outcomes of well-trained high output nurse cataract surgeons are just as good as that of ophthalmologists. However, like all surgeons, their practice must continue to be periodically supervised and audited by others as well as auditing their own work.

The most important of these are glaucoma, diabetic retinopathy and wet macular degeneration. They are all found throughout the world and in all communities. These are major causes of avoidable blindness but have not been given the same high priority in the VISION 2020 programme because blindness from these causes cannot be prevented quite so easily and they do not cause as much visual loss as cataract and refractive error in poor countries, where the life expectancy is shorter.

About 6 million people are blind from glaucoma. Glaucoma is a disease that causes irreversible damage to the optic nerve (see Chapter 15). However, if the disease is detected in an early stage, surgical or medical treatment may be given to prevent blindness from developing.

Diabetic retinopathy is the ophthalmic complication that commonly occurs with diabetes. Once the patient has gone blind, it is not possible to recover the vision. However, if the changes on the retina are detected at an early stage, education and interventions aimed at improving diabetic control as well as laser treatments for the eye can prevent the disease progressing, and even reverse some of the changes if done early enough. There has been an enormous increase in the number of diabetics worldwide, particularly in South Asia, probably because of dietary changes and increased life expectancy in this region. Therefore, diabetic retinopathy has become much more common. Unfortunately, patients need regular examinations to detect retinopathy, as well as good education and then lasers and possibly surgery for treatment. All of these are expensive and inaccessible for much of the world's population.

Until the last 10 years, AMD has been untreatable. However, the development of anti-vasoendothelial growth factor drugs, which are injected into the eye, has enabled one type – ‘wet’ – of AMD to be treated. The more common ‘dry’ type remains untreatable. The treatment does not reverse the damage, but can stop it progressing, and often needs to be repeated many times. The technology needed to assess the retina before and after treatment, as well as the regular eye examinations and the treatment itself, are unfortunately too expensive for most of the world's population.

There are numerous eye diseases that currently cannot be prevented or treated. The most important among these are degenerative and vascular retinal conditions, in particular dry AMD, and retinal vein and artery blockages, which are both relatively common in older people. There are also numerous inherited and congenital diseases of the retina, optic nerve and cornea, such as retinitis pigmentosa, hereditary optic atrophy and corneal dystrophies. Fortunately most of these are rare, but they usually occur in children or young adults and therefore will cause a whole life of visual loss. These diseases that cannot be treated or prevented are the main causes of blindness in rich countries. They are present just as much in poor countries but their significance is less because they are outnumbered by the treatable and preventable causes of blindness. The VISION 2020 programme was not originally focussing on these conditions, but Universal Eye Health has included the very important goal of providing visual aids and assistance to visually impaired people (see above).

Visual loss has enormous effects on home life, social life and working life. It is impossible to accurately calculate the true cost of this for the individual visually impaired person, their community and their country. However, it is clear that the ‘cost’ is enormous. A study in Australia highlighted some of the factors associated with visual loss that are particularly expensive:

There are several ways of estimating the precise economic benefits of treating eye disease, which are beyond the scope of this book. However, it is absolutely clear that the treatment of preventable eye disease, and particularly cataract and refractive error, which is relatively cheap and very effective, provides enormous economic benefits to the person, their community and their country. Cataract surgery is undoubtedly the single most cost-effective operation in the world.17

There is an enormous shortage of ophthalmic care workers in poor countries. This limits the potential to roll out even the most carefully designed and run eye-care programmes. Human resource development involves training people to prevent and treat blinding diseases and also supporting them in their work once they are trained. The precise type of workers needed varies with each country, but typically they are:

The specific set-up of a country or a region's eye care health service will depend on their needs and resources. However, the fundamental principles are that the service should be able to assess and treat as many people as possible, as economically as possible and with an ultimately sustainable service that is part of a universal healthcare system. A critical requirement is that the many people involved in providing healthcare work together as a team. The management of most serious eye diseases of poor countries requires people with many different skills and training, all of whom depend on each other to do their job carefully and thoroughly.

As discussed above, many blinding eye diseases that are common in poor countries are best managed with prevention rather than treatment. These include xerophthalmia, trachoma and onchocerciasis. Other diseases, such as diabetic retinopathy and glaucoma must be detected early in the community through community eye health programmes and then referred for treatment. Therefore, prevention and community health must play a major part in any eye care programme.

Curative medicine attracts health practitioners for several reasons:

Preventive medicine can seem much less attractive than curative medicine. The clinical work is often repetitive and boring, and administration takes up a lot of time. However, there is far more potential to make a major difference to the prevalence of blindness in a community.

Health education forms a vital part of community health. Much eye disease and blindness is caused by poor hygiene or nutrition, or is related to the lifestyle of the community. The only real and lasting solution to these problems will come from within the community itself when people become aware of the importance of good nutrition and hygiene, and healthy living. Health education presents a very different sort of challenge – to win the confidence of communities and their leaders and persuade them to alter some of their traditional customs and ways of life. Health education is most effective when the stimulus for change comes from within the community itself rather than from outside it, i.e. when they understand the importance of the intervention for their own health and well-being. The key concept of health education is ‘ownership’. If the community feels that the health service in some way belongs to them and is for them and they have some part in being responsible for it, then they are much more likely to use it properly, and to respond to suggestions from health care professionals.

This is the third main aim of the VISION 2020 plan; the aim is to provide universal coverage and access to eye care services that are required to prevent and treat visual loss. This requires suitably located primary, secondary and tertiary units for eye care. The infrastructure of eye care must have both a hospital base and a community base which support each other. The community health worker can identify and send the right patients to hospital for treatment. High quality, successful hospital treatment will then encourage and strengthen the acceptance of the community health worker within the community and encourage more patients to attend. There is little point in having lots of teaching hospital eye units in which complex surgery can be done, but no-one to dispense vitamin A capsules in the community and similarly there is little value in having lots of community screeners who can detect cataract, but no operating theatre in the region where cataract extraction surgery can be done. Infrastructure also includes some less obvious components, e.g. providing transport for people to reach eye units, or places for them to stay if they come for trachoma or cataract surgery. Infrastructure goes hand in hand with the human resources development discussed above, as sparkling new clinics and operating theatres are useless without health-care professionals to work in them.

The infrastructure may also require the use of mobile eye care provision. This can take the form of specifically organised campaigns or outreach activity that comes from a larger clinic or health centre. It can be advantageous to take the service closer to the patient for several reasons:

There are numerous examples of the success of taking the treatment to the community, e.g. the uptake of trachoma surgery is much higher if the surgery is taken to the villages than when it is done in health centres and hospitals. Similarly mass vaccinations or vitamin A supplement campaigns reach many more people when they are taken to the community. The vertical campaign model of healthcare is often not sustainable. However, outreach that is organised in a pre-existing health centre or hospital and uses the local staff, can be extremely effective, entirely sustainable and still fit within the ‘normal health system’.

Eye care requires specific and sometimes expensive equipment. Good eye care planning and services depend on the appropriate equipment being supplied, serviced and kept up-to-date. This equipment needs to be of high quality, but affordable and durable. In a community clinic, torches, log books and simple stationary may be enough for some screening programmes, while in a hospital surgical equipment and even lasers may be required. Health care and medical treatment is becoming more and more sophisticated and technologically advanced. This is particularly true in ophthalmology where there have been major advances in technology in three particular areas:

Unfortunately, all this technology is very expensive and even rich countries are finding that they must put cash limits on health care.

Ophthalmologists are like all professional people, they want to be up-to-date with the most recent techniques and have the most modern equipment. However, this can make them ‘blind’ to the real needs of the community. Although this does happen in rich countries, it is a much bigger problem in poor countries where there is a huge gap between sophisticated care that is available in the big cities and the lack of access to care of many poor patients in rural areas.

Any programme of health care must be cost effective to be of value to poor people. Reducing the cost while maintaining the quality is one of the biggest challenges of health care in poor countries. People often think that cheap medical care is bad medical care. There are indeed a few techniques which need expensive equipment and take a long time to perform. However, most eye problems can be treated simply, quickly and effectively using relatively unsophisticated equipment. It should be possible to provide an eye care service that even the poorest people can afford. Indeed, all the major causes of preventable world blindness, with the exception of diabetic retinopathy, are either treatable or preventable at very reasonable cost. Often the biggest challenge and greatest expense of healthcare in poor countries is not the cost of the actual treatment, but the cost of providing a nationwide service and reaching people in remote, rural areas.

In rich countries, there is a fairly similar pattern of eye disease throughout the country. There may be some racial differences but overall the blindness rates are fairly similar. However, in poor countries there may be quite marked differences in diseases between one area and another. The following are some examples of this:

Because eye diseases can vary so much from area to area, any plans for treatment and prevention must be carefully planned and flexible. For example, in xerophthalmia causing corneal ulceration and blindness in young children, it may be appropriate to solve this problem by nutritional advice in one area, adding vitamin A to the food in another and measles vaccination in yet another.

When a patient is visually impaired or blind and no treatment is possible, many health practitioners feel that this is the end of their responsibility and there is little more they can do. However, for the patient it means the beginning of a new and very difficult period in their life and they need all the help, support and encouragement that are available. With appropriate support and low vision aids, a severely visually impaired person can have a full working, home and social life. But without these, they can easily become a recluse. It is a responsibility of the health practitioner who sees the blind 24or visually impaired patient, to help them access any support that is available to them. Most countries have some sort of low vision and rehabilitation for blind or visually impaired people. These are usually run by appropriately trained staff. In rich countries, these services are usually very effective and allow the patient to get vision aids, improvements in their home, and social security benefits. However in poor countries there are many more blind people, a great shortage of trained rehabilitation care workers and of equipment for aiding people with sight loss.

The purpose of rehabilitation is to help the patient to come to terms with their visual impairment, and to try to overcome and prevent as much as possible the disability and handicap.

The United Nations has listed five principles in the care and rehabilitation of disabled people: independence, participation (in society), care, self-fulfilment and dignity. The following are a few examples of what can be done to help people with visual impairment to achieve these goals:

In all communities there are people who treat and attempt to heal patients by traditional methods. There are many different types of traditional healing, such as the use of herbs, homeopathy, or acupuncture or in some cases 25spiritual methods such as divination. There are also traditional methods of surgery, in particular, the operation of couching for cataract, or other techniques like applying cautery to the skin. Those of us trained in orthodox ‘western’ medicine tend to be dismissive of these alternative healers. If we have seen children's eyes destroyed by some toxic medication given for conjunctivitis or someone blinded after couching for cataract, we will probably feel both totally opposed to these methods and superior to the traditional healers, with some justification. Modern orthodox medicine is rightly proud of its rigorous training and scientific method. However, we need to look realistically at the whole situation.

Increasingly, health workers have tried to encourage communication and co-operation with traditional healers rather than condemnation. One way has been to invite traditional healers into hospitals or clinics or even into operating theatres. The foundation for co-operation is mutual respect. Where this has occurred there have been opportunities to learn from traditional healers how local people think of disease and how they react to it. There have also been opportunities to teach traditional healers some of the ideas of modern medicine. Where there has been good co-operation, some traditional healers are happy to refer patients when the problem is beyond them, for instance a blind patient with cataract.

This chapter is all about generalisations and ideas. It is important to finish by considering the individual blind person and his personal needs. The late founder of the International Agency for the Prevention of Blindness, Sir John Wilson, who was himself blind, said of blindness, ‘Only in statistics do people go blind by the millions. Each person goes blind by himself.’ Each unnecessarily blind person brings suffering and deprivation to himself or herself and their family. In addition, there is the frustration of being useless and totally dependent on others. It is harder being blind in those parts of the world where there is no education, rehabilitation or social welfare for blind people.