Non-trachomatous corneal opacities in the Gambia--aetiology and visual burden.

AIMS: National blindness surveys conducted in the Gambia in 1986 and 1996 showed an increase in blindness and visual impairment from non-trachomatous opacity. This study aimed to investigate the aetiology of these opacities and to assess the resulting visual burden. METHODS: A population-based, randomised blindness survey was conducted in the Gambia in 1996. Patients with visual impairment or blindness were examined by an ophthalmologist with a slit lamp. Causes of corneal opacity were determined as accurately as possible by clinical history and examination. RESULTS: A total of 154 patients with non trachomatous corneal opacity were examined of whom 39 had bilateral opacities and 115, unilateral. Causes included corneal infection, measles/vitamin A deficiency, harmful traditional practices and trauma (unilateral scarring). Overall, corneal pathology alone was responsible for bilateral visual impairment or blindness in 19 (12%) patients and unilateral visual impairment or blindness in 88 (57%) patients. Those patients with bilateral visual impairment or blindness (mean age 59, SD) were older (P= 0.003) than others (mean age 44, SD = 20). The use of harmful traditional eye practices was associated with bilateral corneal blindness or visual impairment (RR = 2.63, 95% CI 1.11-6.21, P = 0.04). Although none of the corneal scars reported here were attributed to trachoma, in patients over the age of 45, the prevalence of trachomatous conjunctival scarring in this group was 38.8% compared to 19.4% of the whole nationwide sample. DISCUSSION: Strategies for the prevention (including the quest for cheaper anti-microbial drugs and co-operation with traditional healers) and surgical treatment of these corneal opacities are discussed.

The management of chronic pain in Switzerland: a comparative survey of Swiss medical specialists treating chronic pain.

Chronic pain management by Swiss specialist physicians with the primary hypothesis that pain clinic practitioners conform better to good practice (interdisciplinarity, diagnostic/therapeutic routines, quality control, education) than other specialists treating chronic pain was surveyed. Management of all types of chronic pain by pain clinic practitioners and rheumatologists, oncologists or neurologists was compared via a mailed questionnaire survey (n=125/group). Two hundred and twenty-nine (46%) of 500 mailed questionnaires were returned with similar group return rates. Eighty-six percent of responders find chronic pain therapy very difficult/difficult; they estimate only 45% of these patients achieve good outcomes. Twenty-three per cent of responders belong to an interdisciplinary pain centre, but 72% of chronic pain patients are treated by responders alone. Fifty-nine percent never/only occasionally use therapeutic algorithms, 38% use formal pain diagnostic procedures, 20% have a pain quality control programme. Fifty-one percent lack past pain education, 37% do not attend continuing pain education, 69% agree that pain education is their greatest need. Pain clinic practitioners are more interdisciplinary and use more pain diagnostics than other specialists. They are matched by oncologists in education and success in therapeutic escalation, and bettered by them in algorithm use. Pain clinic practitioners and oncologists bring particular-differing-skills to chronic pain management compared to rheumatologists and neurologists. Chronic pain management diversity may result from differences in malignant and benign pain, and its generally being provided by the speciality treating the underlying cause. This survey identifies targets for improvement in areas fundamental to good chronic pain practice: interdisciplinarity, diagnostic/therapeutic tools, quality management and education.

Evaluation of a national eye care programme: re-survey after 10 years.

AIM: To re-survey the Gambia after an interval of 10 years to assess the impact of a national eye care programme (NECP) on the prevalence of blindness and low vision. METHOD: Comparison of two multistage cluster random sample surveys taking into account the marked increase in population in the Gambia, west Africa. Samples of the whole population in 1986 and 1996 were taken. The definition of blindness is presenting vision less than 3/60 in the better eye, or visual fields constricted to less than 10 degrees from fixation. Low vision is less than 6/18 but 3/60 or better. Causes of blindness were determined clinically by three ophthalmologists. RESULTS: The crude prevalence of blindness fell from 0.70% to 0.42%, a relative reduction of 40%. During the same 10 year period, the population increased by 51% from 775 000 to 1 169 000. When the results were standardised for age, a west to east gradient was found for changes in risk of blindness over the 10 year period. This matched the phased west to east introduction of the NECP interventions. There was a modest but significant increase in the risk of low vision across the whole country. CONCLUSIONS: The overall reduction in risk of blindness, in those areas where the NECP has been active, appears to justify the programme and the support of donor organisations. The low vision cases due to cataract must now be addressed.

Consensus statement. Global burden of tuberculosis: estimated incidence, prevalence, and mortality by country. WHO Global Surveillance and Monitoring Project.

OBJECTIVE: To estimate the risk and prevalence of Mycobacterium tuberculosis (MTB) infection and tuberculosis (TB) incidence, prevalence, and mortality, including disease attributable to human immunodeficiency virus (HIV), for 212 countries in 1997. PARTICIPANTS: A panel of 86 TB experts and epidemiologists from more than 40 countries was chosen by the World Health Organization (WHO), with final agreement being reached between country experts and WHO staff. EVIDENCE: Incidence of TB and mortality in each country was determined by (1) case notification to the WHO, (2) annual risk of infection data from tuberculin surveys, and (3) data on prevalence of smear-positive pulmonary disease from prevalence surveys. Estimates derived from relatively poor data were strongly influenced by panel member opinion. Objective estimates were derived from high-quality data collected recently by approved procedures. CONSENSUS PROCESS: Agreement was reached by (1) participants reviewing methods and data and making provisional estimates in closed workshops held at WHO's 6 regional offices, (2) principal authors refining estimates using standard methods and all available data, and (3) country experts reviewing and adjusting these estimates and reaching final agreement with WHO staff. CONCLUSIONS: In 1997, new cases of TB totaled an estimated 7.96 million (range, 6.3 million-11.1 million), including 3.52 million (2.8 million-4.9 million) cases (44%) of infectious pulmonary disease (smear-positive), and there were 16.2 million (12.1 million-22.5 million) existing cases of disease. An estimated 1.87 million (1.4 million-2.8 million) people died of TB and the global case fatality rate was 23% but exceeded 50% in some African countries with high HIV rates. Global prevalence of MTB infection was 32% (1.86 billion people). Eighty percent of all incident TB cases were found in 22 countries, with more than half the cases occurring in 5 Southeast Asian countries. Nine of 10 countries with the highest incidence rates per capita were in Africa. Prevalence of MTB/HIV coinfection worldwide was 0.18% and 640000 incident TB cases (8%) had HIV infection. The global burden of tuberculosis remains enormous, mainly because of poor control in Southeast Asia, sub-Saharan Africa, and eastern Europe, and because of high rates of M tuberculosis and HIV coinfection in some African countries.

Determinants of attendance and patient satisfaction at eye clinics in south-western Uganda.

PURPOSE: To identify the reasons for subjects deciding to attend or not attend local and referral ophthalmology clinics in south-west Uganda, and to establish the levels of satisfaction of clinic attenders with the services they received. METHODS: A population survey identified subjects with ocular conditions who were referred to the local clinic or the district hospital. All non-attenders and a group of attenders were interviewed at home. RESULTS: 31% of those referred did not attend the local clinic. The most common reasons were 'too busy' (29%) or 'unwilling to buy spectacles' (17%). Less than half of attenders were satisfied, mainly because of no perceived clinical improvement or having to buy spectacles. Only 13% of those referred to the district hospital clinic attended. The main reasons for non-attendance were high transport cost and fear of the clinic. CONCLUSION: Attendance and satisfaction with the community ophthalmology service could be improved by more intensive motivation and explanation for patients, and assistance with spectacle and transport costs. The use of aphakic motivators should be tested in this context.

Causes and prevalence of non-vision impairing ocular conditions among a rural adult population in sw Uganda.

Information is scanty about the extent of ocular morbidity in developing countries, particularly for non-vision impairing conditions (NVIC), although these constitute the majority of consultations in eye clinics. We have conducted a survey to determine the prevalence and causes of NVIC in a Ugandan adult population and compared our findings with the work pattern of the district hospital. Adults were screened using Snellen's illiterate E chart and those found with visual impairment (acuity less than 6/18) in either eye were referred to a low-vision clinic, and those with obvious ocular disease or symptoms, but without visual impairment, to an outreach clinic. A total of 2886 (53%) out of 5479 adults were screened. Of these, 257 (8.9%) were referred to the outreach clinic, of whom 173 (67%) attended. Of those attending the low-vision clinic 83% had visual impairment confirmed, and 92% of those attending the outreach clinic were confirmed not to have visual impairment. The four commonest NVIC observed at the outreach clinic were: presbyopia (48%), allergic conjunctivitis (20%), early cataract (9%) and infective conjunctivitis (8%), the same conditions as those most commonly seen at the district hospital. In this community, over 80% of NVIC are caused by four conditions which are potentially either correctable, operable or treatable. Training health workers to recognise and treat these conditions would serve the great majority of eye patients. Hospital activity data can be used cautiously to assess the relative frequency of NVIC in the community.

Modelling uveal melanoma.

BACKGROUND/AIM: There has been no consistent pattern reported on how mortality for uveal melanoma varies with age. This information can be useful to model the complexity of the disease. The authors have examined ocular cancer trends, as an indirect measure for uveal melanoma mortality, to see how rates vary with age and to compare the results with their other studies on predicting metastatic disease. METHODS: Age specific mortality was examined for England and Wales, the USA, and Canada. A log-log model was fitted to the data. The slopes of the log-log plots were used as measure of disease complexity and compared with the results of previous work on predicting metastatic disease. RESULTS: The log-log model provided a good fit for the US and Canadian data, but the observed rates deviated for England and Wales among people over the age of 65 years. The log-log model for mortality data suggests that the underlying process depends upon four rate limiting steps, while a similar model for the incidence data suggests between three and four rate limiting steps. Further analysis of previous data on predicting metastatic disease on the basis of tumour size and blood vessel density would indicate a single rate limiting step between developing the primary tumour and developing metastatic disease. CONCLUSIONS: There is significant underreporting or underdiagnosis of ocular melanoma for England and Wales in those over the age of 65 years. In those under the age of 65, a model is presented for ocular melanoma oncogenesis requiring three rate limiting steps to develop the primary tumour and a fourth rate limiting step to develop metastatic disease. The three steps in the generation of the primary tumour involve two key processes-namely, growth and angiogenesis within the primary tumour. The step from development of the primary to development of metastatic disease is likely to involve a single rate limiting process.

Trachoma in The Gambia.

BACKGROUND: As part of the second National Survey of Blindness and Low Vision in the Gambia carried out in 1996, all survey participants were examined for signs of trachoma. The findings were compared with the results of the first survey in 1986, which used the same sampling strategy. METHODS: A multistage stratified cluster random sample, with proportional probability sampling, was obtained. Stratification included settlement size (less than 400 residents, and 400 and more residents). All subjects were examined for trachoma using the simplified WHO grading system. RESULTS: Of the sample of 14,110 people, 13,047 (92.5%) were examined. Active inflammatory trachoma (grade TF or TI) was found in 3.0% of all age groups and 5.9% of children aged 0-9 years old. Trichiasis was found in 3.3% and trachomatous corneal opacities in 0.9% of adults aged 30 and over. The prevalence of blinding trachomatous corneal opacities was 0.02%, compared with 0.10% 10 years previously. CONCLUSION: Compared with a previous national survey undertaken in 1986, prevalence of active trachoma has fallen by 54%. There has been an 80% relative reduction in blinding trachomatous corneal opacities over the 10 year period.

Epidemic optic neuropathy in primary school children in Dar es Salaam, Tanzania.

BACKGROUND: An epidemic of bilateral optic neuropathy is affecting large numbers of people aged between 10 and 40 in Dar es Salaam, the capital city of Tanzania. The disease is characterised by acute onset of bilateral visual impairment, bilateral impairment of colour vision, and a characteristic temporal pallor of the optic discs. The disease often occurs in association with peripheral neuropathy and sensorineural hearing loss. This report presents the first data on disease prevalence in adolescents, based on a rapid assessment of schoolchildren. METHODS: Three schools in Dar es Salaam were visited and all children aged between 10 and 16 were screened for the disease. RESULTS: The prevalence of bilateral optic neuropathy among the schoolchildren is estimated to be 1.0% (95% CI 0.5-1.4%). This suggests that 5000 children (95% CI 2600-7300) aged 10-16 in Dar es Salaam may have the disease. CONCLUSION: The results of this rapid assessment indicate this epidemic is a major public health problem. The prevalence of the disease in the community is likely to be far higher than found in this survey because children with the disease may have withdrawn from school. As the disease predominantly affects young adults, resulting in impaired vision and hearing, the economic and social consequences are enormous.

Nationwide prevalence study of hypertension and related non-communicable diseases in The Gambia.

The prevalence of hypertension, diabetes and obesity in The Gambia was assessed in a 1% population sample of 6048 adults over 15 years of age, 572 (9.5%) subjects were hypertensive according to WHO criteria (a diastolic blood pressure (DBP) of 95 mmHg or above and/or a systolic blood pressure (SBP) of 160 mmHg or above); 325 (5.4%) had a DBP of 95 mmHg or above, and 39 (2.3%) a DBP of 105 mmHg or above; 428 (7.1%) had a SBP of 160 mmHg or above. By less conservative criteria (a DBP of 90 mmHg or above and/or SBP of 140 mmHg or above), 24.2% of subjects were hypertensive. The prevalence of hypertension was similar in the major ethnic groups and in urban and rural communities. Age and obesity were risk factors for hypertension; female sex was an additional risk factor for diastolic hypertension. Several communities had a prevalence of diastolic hypertension double the national rate, and significant community clustering of diastolic hypertension (P < 0.01) was confirmed by Monte Carlo methods. Genetic and/or localized environmental factors (such as diet or Schistosoma haematobium infection), may be involved 140 (2.3%) subjects were obese. Obesity was associated with female sex, increasing age, urban environment, non-manual work and diastolic hypertension. Only 14 (0.3%) subjects were found to be diabetic. Hypertension appears to be very prevalent in The Gambia, with a substantial population at risk of developing target organ damage. Further studies to delineate this risk and appropriate interventions to reduce it are needed.

Reduction of trachoma in a sub-Saharan village in absence of a disease control programme.

BACKGROUND: Trachoma is a leading cause of blindness in the developing world and is most prevalent among people who live in poor rural communities in arid locations. METHODS: We analysed the results of surveys of trachoma prevalence in Marakissa, a rural village in The Gambia. These surveys were undertaken in 1959, by the Medical Research Council, and in 1987 and 1996 by the Gambian National Eye Care Programme. FINDINGS: During this 37-year period, the prevalence of active inflammatory trachoma among children aged 0-9 years fell from 65.7 cases per 100 children in 1959 to 2.4 cases per 100 children in 1996. The prevalence also fell dramatically among people of 10-19 years (52.5 to 1.4 per 100) and among people of 20 years and older (36.7 to 0 cases per 100). INTERPRETATION: The dramatic fall in disease occurrence was paralleled by improvements in sanitation, water supply, education, and access to health care in the village. Of particular importance is that the decline in trachoma occurred without any trachoma-specific intervention.

PIP: Trachoma, an eye infection caused by Chlamydia trachomatis, is a leading cause of blindness in developing countries. Risk factors include lack of facial cleanliness, poor access to water supplies, lack of latrines, and a large number of flies. Its prevalence is disproportionately high among women and children in poor rural communities. To assess trends in the prevalence of active inflammatory trachoma in Marakissa, a typical small rural village in the Gambia divided into family compounds, the results of eye examinations conducted in 1959, 1987, and 1996 were compared. Among children under 10 years of age, the prevalence of active trachoma infection dropped from 65.7 cases per 100 in 1959 to 2.4 per 100 in 1996. Declines were also recorded among children 10-19 years old (from 52.5 to 1.4/100) and among those 20 years and older (from 36.7 to 0 cases/100). This dramatic fall, which occurred without any specific trachoma control programs in the area, is presumed attributable to both improvements in socioeconomic standards and the training of village health workers and traditional birth attendants in eye care.

Trends in eye cancer mortality among adults in the USA and England and Wales.

Trends in eye cancer mortality are presented for the USA and England and Wales during the period 1955-89. Mortality rates have fallen by 58% in the USA during this period. The fall in mortality is paralleled by an equal fall in incidence rates in the USA. In England and Wales, mortality rates and incidence rates have remained relatively constant during the last three decades. The explanation for these differences between the USA and England and Wales is unknown.

Causes of suppurative keratitis in Ghana.

AIMS: Suppurative keratitis is a serious problem in all tropical countries, but very little information is available about the causative organisms in Africa. The objectives were to identify the causative organisms and the proportion of cases caused by fungi in southern Ghana, and to determine whether correct decisions about treatment could be made on the basis of Gram stain in the eye clinic. METHODS: Scrapings were taken from corneal ulcers of consecutive new patients presenting at Korle Bu Hospital, Accra, and inoculated on 'chocolate' and Sabouraud's agars. Further scrapings were taken for Gram staining and interpretation in the eye clinic. Duplicate slides were assessed by an experienced microbiologist in the UK. RESULTS: One or more organisms were cultured from 114 of 199 patients (57.3%), the most common being Fusarium species, Pseudomonas aeruginosa, and Staphylococcus epidermidis. Fungi, alone or in combination, were isolated from 56% of the patients who had positive cultures. In total, 122 patients (61.3%) had their treatment either determined or altered based on the results of the microbiological diagnosis; in 87 of these solely on the basis of direct microscopic examination. CONCLUSIONS: Infection by filamentous fungi accounted for more than half of the ulcers from which cultures were obtained. Both training in technique and experience in interpretation are necessary for microscopy based diagnosis by staff in the clinic to be of greatest value. Direct microscopy was particularly useful for detecting fungi.

Mortality before and after HIV infection in the complete UK population of haemophiliacs. UK Haemophilia Centre Directors' Organisation.

During 1977-91, 6,278 males diagnosed with haemophilia were living in the UK. During 1979-86, 1,227 were infected with the human immunodeficiency virus (HIV-1) as a result of transfusion therapy (median estimated seroconversion date, October 1982). Among 2,448 with severe haemophilia, the annual death rate was stable at 8 per 1,000 during 1977-84; during 1985-92 death rates remained at 8 per 1,000 among HIV-seronegative patients but rose steeply in seropositive patients, reaching 81 per 1,000 in 1991-92. Among 3,830 with mild or moderate haemophilia, the pattern was similar, with an initial death rate of 4 per 1,000 in 1977-84, rising to 85 per 1,000 in 1991-92 in seropositive patients. During 1985-92, there were 403 deaths in HIV seropositive patients, whereas 60 would have been predicted from rates in seronegatives, suggesting that 85% of the deaths in seropositive patients were due to HIV infection. Most of the excess deaths were certified as due to AIDS or to conditions recognized as being associated with AIDS.

Solar ultraviolet radiation and ocular disease: a review of the epidemiological and experimental evidence.

Exposure to solar ultraviolet radiation has been linked, at some point, with more than a dozen eye diseases. Some of these associations are based solely on anecdotes, while others have been subjected to epidemiological investigations. For each eye disease, the evidence for an association with ultraviolet radiation is presented and evaluated. The only eye disease for which there is sufficient evidence of a causal association in humans is photokeratitis. For several eye diseases (climatic droplet keratopathy, pterygium, cataract) there is limited evidence for an association, while for other diseases (uveal melanoma, macular degeneration) there is either little support for an association or inadequate data on which to base an assessment.

Methodological considerations for future epidemiological studies of solar ultraviolet radiation and eye disease.

This paper reviews current methodological and epidemiological issues that face researchers interested in examining the relationship between exposure to solar ultraviolet radiation and cataract and other eye diseases. Key areas addressed include study design, measurement of ocular exposure, potential confounding and modifying factors, and evaluation of the impact of ozone depletion on eye diseases.