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IF doing cataract surgery in mud huts is something you find appealing, then you might want to get to know David Yorston FRCOphth. The British-trained ophthalmologist spends much of his time in developing countries providing treatment to the world's poor and training other healthcare workers to do the same. He lived and worked in East Africa from 1985 to 2000. He does this to support Vision 2020, an international programme that has the ambitious goal of eliminating preventable and treatable blindness by the year 2020. Vision 2020 is a collaboration between the World Health Organisation and more than 20 non-governmental organisations. To begin with, Vision 2020 has four key mandates. One is to increase the awareness of blindness as a major public health problem. It's clearly an issue because nearly 180 million people globally have some degree of visual impairment, with 45 million of them being blind. While 90% of the world's blind live in developing countries, about 80% of blindness is preventable, he said. Globally, the economic burden of blindness is estimated to be about $25-billion ( US ). A second mandate is to control the major causes of blindness. This means finding ways to get care to people living in poverty, including those who live in distant, rural communities. The third is to train ophthalmologists and other eye-care personnel to provide good care to people in need, and this means creating an infrastructure to manage the problem, the fourth mandate. Right now, about 20 million people have lost their vision because of cataracts, making this the most common cause of blindness. With the world's population expected to grow from six billion to eight billion by the year 2020, cataract blindness will increase to 50 million people, unless delivery of cataract services is improved. Battling this problem means increasing the amount of cataract surgery performed. In a country such as Canada , close to 5,000 cataract surgeries are done per million people per year. In most of Africa it's less than 500, noted Dr Yorston. In many African countries there is a lack of access to eye care because there just aren't enough eye workers. Plus, ophthalmologists tend to live in the cities and are difficult for people in rural villages to reach. "What is needed are community-based eye workers who can identify cataract patients in their own homes and villages. They can assist the patient to come for surgery, for instance, by collecting a group of patients and hiring a minibus to transport them," Dr. Yorston said. Something else that can help is to train cataract surgeons, something Dr. Yorston helps with. "They are para-medical staff who receive training in eye care, then a one-year course in cataract surgery. This is a good solution for countries with few ophthalmologists and a low cataract rate," he said. But one needs to be politic when working in communities. "You don't want to undermine local attempts to achieve self-reliance," he said. For instance, if you offer free services, it takes business away from others providing services. Teaching new skills to care providers can go a long way, though. But good care with good outcomes is vital. If the results of surgery are poor, then people won't even consider going in for treatment. The relatively simple step of prospectively monitoring outcomes has been shown to improve the results of surgery, he said.
Technical advances that can be used in the setting of a developing country in cataract surgery improve outcomes too, but they need to be the sort that can be used in less technical environments, and have a low cost. "At present, there is great interest in sutureless ECCE. This offers some of the advantages of phaco at a fraction of the cost," he said. With sutureless ECCE, one creates a long scleral tunnel followed by hydro-dissection of the nucleus. The nucleus is then removed by hydro-expression or by traction, and a rigid PMMA lens is inserted. Dr. Yorston described a series of 500 sutureless ECCE operations performed at the Lahan Hospital in Nepal . Surgeons found that the operation was quick to do (it took only about five minutes per patient) and cost less than $10 per case. Six weeks after surgery, 70% of the patients could see at least 6/18 without glasses and 95% had best corrected vision of 6/18 or better. "Using a rigid PMMA intraocular lens brings the cost of consumables was down to less than ten dollars. Unless cataract surgery is affordable, we will never be able to eliminate cataract blindness. Controlling costs is an unpopular notion, but it must be done," he said. Dr. Yorston argued that the best way to get the costs down is to increase the number of surgeries done. Once the basic overhead of opening a clinic is covered, costs decrease as the volume of patients increases. Most patients never get the opportunity to go for surgery, so making it accessible in their own villages and communities, such as through visiting surgeon programs, is a key step. If you are considering volunteering your services, don't expect to operate in modern surroundings. Dr. Yorston is no longer surprised if he finds himself having to set up a surgical clinic in a grass hut, an old barn or tent. "It's a different environment with different equipment, you have to develop new sets of skills," he said.
As well as eliminating cataract blindness, Vision 2020 is also seeking to eradicate blindness caused by trachoma. A single dose of azithromycin is as effective as a six-week course of topical tetracycline for trachoma, but it is also much more expensive. Donation programmes are examining the effectiveness of mass distribution of azithromycin in communities with severe trachoma. Face cleaning can be a good preventive strategy, though for many ophthalmologists this isn't usually on the list of things they think about recommending to patients. But in the environment of developing countries, even this apparently simple step has its challenges. "A trial in Tanzania showed that an intensive health education programme to encourage face-washing resulted in a small reduction in severe trachoma. However, it is difficult to change behaviour by education alone. Where the water supply is poor, levels of hygiene will also be poor," Dr. Yorston said. Reducing the fly population is another strategy that reduces trachoma transmission, but large-scale fly-control programs that rely on insecticides are too costly. However, there are alternative methods, such as encouraging the use of pit latrines where they are not used, to reduce the fly population and so combat this eye infection. With the various smaller successes Vision 2020 has seen, it shows "that our goal of eradicating avoidable blindness is now achievable," Dr. Yorston said. PAEDIATRIC CATARACTS KEY CAUSE OF VISION LOSS
Paediatric vision loss is a huge problem in developing countries, and childhood cataracts pose a formidable challenge in this population. At this point, the results of cataract surgery in children tend to be poor. One study in Uganda found that over 50% of operated eyes had a visual acuity of less than 6/60. This was due to a combination of factors, including late presentation, a lack of facilities and equipment, and poor correction of aphakia. Because of the inadequate correction of aphakia, the use of intraocular lenses, even in infants as young as three months, may be a possible solution, although it is controversial in some circles. In Kenya , Dr Yorston looked at 70 children and found that more than half could see 6/18 or better, and less than 4% had vision worse than 6/60, suggesting IOLs could improve outcomes. Retinopathy of prematurity (ROP) is a more complex problem in developing countries too. It is more common, and occurs in larger and less premature babies than in developed countries. In Latin America , 25% of childhood blindness is caused by ROP, and a Brazilian study showed the mean birth weight of infants with Stage-3 disease was over 1,000g, noticeably higher than in North America . "The ideal screening criteria for Third World babies are not yet known, but one current suggestion is that all babies weighing less than 1,750g should be screened. Screening could dramatically reduce the rate of blindness in this population," he noted. While pretty much wiped-out in developed countries, trachoma is still a leading cause of blindness in the poorest and most remote parts of the world. To tackle trachoma, Vision 2020 uses what they call the SAFE strategy: Surgery, Antibiotic, Facial cleanliness and Environmental improvements. It's "an integrated approach aimed at preventing transmission, treating infection and curing trichiasis," he said. David Yorston, FRCOphth |
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