Prevalence of blindness and low vision of people over 30 years in the Wenchi district, Ghana, in relation to eye care programmes

Task-shifting and the recruitment and retention of eye care workers in under-served areas: a qualitative study of optometrists' motivation in Ghana and Scotland

AIM

To assist policy-makers in improving access to eye care in under-served areas by analysing the relationship between motivational factors affecting the uptake of task-shifting in eye care and the recruitment and retention of optometrists in remote and rural areas.

BACKGROUND

The World Health Organization recommends two key strategies in tackling preventable blindness in under-served areas: improving human resources for health and task-shifting. The relationship between task-shifting and recruitment and retention of eye care workers in under-served areas is unknown. Ghana and Scotland are two countries from different levels of economic development that have notably expanded the roles of optometrists and struggle with rural recruitment and retention.

METHODS

Motivation was explored through semi-structured interviews with 19 optometrists in Ghana and Scotland with experience in remote and rural practice. Framework analysis was used to analyse interviews, explore the relationship between task-shifting and recruitment and retention and create recommendations for policy.

FINDINGS

The main motivational considerations included altruism, quality of life, learning and career opportunities, fulfilling potential, remuneration, stress of decision-making and collaboration. Motivational and demotivational factors for task-shifting and recruitment/retention shared many similar aspects.

DISCUSSION

Recruitment and retention in remote and rural areas require staff be incentivised to take up those positions, motivated to remain and given the adequate resources for personal and professional fulfilment. Task-shifting also requires incentivisation, motivation to continue and the resources to be productive. Many motivational factors influencing recruitment/retention and task-shifting are similar suggesting these two strategies can be compatible and complementary in improving access to eye care, although some factors are culture and context specific. Understanding optometrists' motivation can help policy-makers improve rural recruitment and retention and plan services.

Assessing the Progress towards Achieving "VISION 2020: The Right to Sight" Initiative in Ghana

Purpose

The aim of this study was to analyse eye health delivery in Ghana and examine the progress towards achieving VISION 2020 indicator targets.

Methods

This descriptive cross-sectional study was conducted between October 2017 and May 2018. It used a mixed method approach including desk-based reviews, a questionnaire-based survey of eye facilities in Ghana, and interviews with eye health system stakeholders to collect information on eye health delivery in facilities owned by the Ghana Health Service (GHS), quasigovernmental bodies (security agencies), and Christian Association of Ghana (CHAG). The information was benchmarked against the World Health Organization (WHO) targets for achieving the goals of VISION 2020.

Results

The magnitude of blindness and moderate to severe visual impairment (without pinhole) was 0.9% and 3.0%, respectively. The number of ophthalmologists available at the country level was 80.6% of the VISION 2020 target with optometrists and ophthalmic nurses exceeding targets for VISION 2020. The distribution of human resources was heavily skewed towards two out of the 10 regions in Ghana. Cataract surgical rate was low and met 25% of the WHO target. Basic equipment for refraction was available in the majority of facilities; however, there was a general lack of specialised eye care equipment across the country. Comparatively, CHAG facilities were better equipped than GHS facilities at the same level.

Conclusion

The Government of Ghana should revitalize the goals of VISION 2020 beyond the year 2020 and spearhead a concerted effort to ensure equitable distribution of human and infrastructural resources across the country.

Vision-specific and psychosocial impacts of low vision among patients with low vision at the eastern regional Low Vision Centre

Purpose: To determine vision-specific and psychosocial implications of low vision among patients with low vision visiting the Low Vision Centre of the Eastern Regional Hospital in Ghana.Methodology: This was a descriptive case-control study of 41 patients with low vision and 41 patients with normal vision recruited from the Low Vision Centre of the Eastern Regional Hospital by simple random sampling. Data on vision-specific and psychosocial impacts of low vision was collected using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). Biographical and clinical characteristics such as age, gender, educational status, marital status, employment and income status were gathered from consenting patients. Mann–Whitney U analysis using Statistical Package for Social Scientists (SPSS) was conducted to compare scores on vision-specific and psychosocial subscales of the NEI VFQ-25 between patients with low vision and patients with normal vision.Results: Patients with low vision recorded the lowest score on the driving subscale (median = 8.33, IQR [interquartile range]: 8.33–41.67, n = 41, p < 0.001), as well as on distance activities (median = 35.42, IQR = 16.70–58.80). Psychosocial implications of low vision included high dependency (median = 33.33, IQR = 25.00–50.00), reduced mental health (median = 37.50, IQR = 25.00–50.00) and limitation in partaking in social activities (median = 50.00, IQR = 37.50–78.00).Conclusion: Low vision has both vision-specific and psychosocial implications for the patients. Low vision management and services should therefore be tailored to meet these psychosocial and vision-specific needs to enable patients better accept their visual changes and to be better prepared to use their remaining vision to achieve their daily goals.

Prevalence and Causes of Visual Impairment and Blindness among Cocoa Farmers in Ghana

PURPOSE

To determine the prevalence and causes of visual impairment and blindness among cocoa farmers in Ghana in order to formulate early intervention strategies.

METHODS

A cross-sectional study using multistage random sampling from four cocoa growing districts in Ghana was conducted from November 2013 to April 2014. A total of 512 cocoa farmers aged 40 years and older were interviewed and examined. The brief interview questionnaire was administered to elicit information on the demographics and socioeconomic details of participants. The examination included assessment of visual acuity (VA), retinoscopy, subjective refraction, direct ophthalmoscopy, slit-lamp biomicroscopy and intraocular pressure (IOP). For quality assurance, a random sample of cocoa farmers were selected and re-examined independently.

RESULTS

Moderate to severe visual impairment (VA <6/18 to 3/60 in the better-seeing eye) was present in 89 participants (17.4%) and 27 (5.3%) were blind (presenting VA <3/60 in the better eye) defined using presenting VA. The main causes of visual impairment were cataract (45, 38.8%), uncorrected refractive error (42, 36.2%), posterior segment disorders (15, 12.9%), and corneal opacity (11, 9.5%).

CONCLUSION

The prevalence of visual impairment and blindness among cocoa farmers in Ghana is relatively high. The major causes of visual impairment and blindness are largely preventable or treatable, indicating the need for early eye care service interventions.

Causes of low vision and their management at Korle Bu Teaching Hospital, Accra, GHANA

BACKGROUND

Provision of low vision services to the visually impaired is vital in blindness intervention programs. Such services are avenues for low vision patients to utilize their residual vision in carrying out daily tasks.

AIM

To review the causes of low vision and services provided to low vision patients at Korle Bu Teaching Hospital.

STUDY DESIGN

A retrospective cross-sectional study.

METHODOLOGY

Study subjects were low vision patients who had been referred by ophthalmologists and optometrists from all over Ghana for low vision services. At the Low Vision Centre, patients were re-examined to confirm that they had low vision and were suitable for low vision devices. The visual acuities of all patients was determined using a Snellen chart (with letters and tumbling E chart) followed by anterior and posterior segment examination using a Haagstreit slit lamp biomicroscope and direct and/or indirect ophthalmoscope (Keeler). All patients were refracted for near and distance and best corrected visual acuities were recorded. Patients with best corrected visual acuities of less than 6/18 but better than light 3/60 in the better were considered for low vision devices. Clinical records of low vision patients managed at the Korle Bu Teaching Hospital between March 2005 and December 2014 were examined to determine the main causes of low vision and interventions given. Their demographics, clinical features, services offered and annual trend in low vision uptake were analyzed.

RESULTS

A total of 604 patients managed between March 2005 and December 2014 at the low vision centre of the Korle Bu Teaching Hospital were included in the study. The mean age was 40.55+6.95 years. There was statistically no significant difference between the mean age in either sex; p-value = 1.000. Glaucoma was the leading cause of low vision in 135 (22.35%) of cases, followed by non-glaucomatous optic atrophy 62(10.26 %), retinitis pigmentosa 54(8.94 %), maculopathy 52(8.61 %) and ARMD 48(7.95 %) respectively. Uptake of the low vision services was highest in the second year of commencing the services. Interventions were mainly magnifiers, telescopes, closed circuit television (CCTV), counselling and referral to the School for the Blind.

CONCLUSION

Glaucoma and non-glaucomatous optic atrophy were the predominant causes of low vision, and magnifiers and telescopes were the most commonly prescribed devices.

Cataract Surgical Uptake Among Older Adults in Ghana

OBJECTIVES

In sub-Saharan Africa, cataract surgical services are highly inadequate and surgical uptake for cataract is low. This paper describes cataract surgical uptake among older adults in Ghana.

METHODS

This work was based on World Health Organization's multi-country Study on global Ageing and adult health (SAGE), conducted in six countries including Ghana. Wave one of SAGE in Ghana was conducted in 2007-2008 as collaboration between WHO and Department of Community Health, University of Ghana Medical School. A nationally representative sample of 5571 older adults (≥50 years) and a small sample of persons 18-49 years were interviewed. Data was obtained on uptake of cataract surgery in older adults and analyzed using descriptive measures and chi square for associations in categorical outcome measures.

RESULTS

Overall surgical uptake was 48.9% among older adults and was slightly higher among older men (49.1%) than women (48%). Cataract surgical uptake was relatively higher in the 60-69 years group (55%), urban residents (52.6%) and those living without partners (50%). Educational and income levels of older persons did not affect cataract surgical uptake. Regional differences in cataract surgical uptake existed; was less than 60% in all ten regions (except one), and the two regions with most self-reported cataracts (Ashanti and Greater Accra) had less than 50% uptake.

CONCLUSIONS

Intensive public education, engagement of community groups and increased access to cataract surgery at health facilities and outreach services need consideration at national/sub-national levels. Further investigations to garner equity in national eye care efforts are recommended.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey

PURPOSE

To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population.

METHODS

A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16-39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss.

RESULTS

The mean age of participants was 21.86 years (95% CI: 21.72-21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56-3.72) and 0.79% (95% CI: 0.54-1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden.

CONCLUSION

Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment.

A cross-sectional survey of optometrists and optometric practices in Ghana

PURPOSE

The study was conducted to profile optometrists and optometric practices in Ghana.

METHODS

An online survey was conducted among 146 optometrists, who were registered with the Ghana Optometric Association (GOA). It included questions on their demographics, equipment, ophthalmic procedures routinely conducted and the barriers to providing a full scope of optometric services.

RESULTS

Ninety registered optometrists (62 per cent) responded, their mean age being 28.97 ± 3.36 years. There were more males (68.9 per cent) than females and most had the Doctor of Optometry (OD) degree, the profession's highest degree in Ghana. There were more practitioners in urban centres (71.1 per cent) and most practices had basic optometric instruments, such as direct ophthalmoscopes, slitlamp biomicroscopes and retinoscopes. Many optometrists routinely conducted direct ophthalmoscopy (100 per cent), slitlamp biomicroscopy (87.5 per cent) and contact tonometry (55.7 per cent); however, few provided contact lens (10.2 per cent) and low vision (9.1 per cent) assessments, with 76 per cent stating that it was due to the unavailability of low vision devices, poor sources of contact lenses (27 per cent) and perceived insufficient training (11.2 per cent). Many practitioners (97 per cent) reported the use of diagnostic pharmaceutical agents and therapeutic pharmaceutical agents (96.6 per cent). Most practitioners (52.9 per cent) preferred conferences for the delivery of continuous professional development over publications (26.4 per cent) and internet resources (12.6 per cent).

CONCLUSION

The data elicited in this study provide a basis for addressing the country's unmet eye-care needs and can be used to determine training and support guidelines for the profession.

Self-reported cataracts in older adults in Ghana: sociodemographic and health related factors

BACKGROUND

Changes in function of sensory organs with increasing age have significant impact on health and wellbeing of older persons. This paper describes cataract, a chronic eye condition, self-reported among older adults in Ghana and the need for improving access to eye care services.

METHODS

This work was based on the World Health Organization's multi-country Study on global AGEing and adult health (SAGE), conducted in six countries including Ghana. SAGE Wave 1 in Ghana was conducted in 2007-2008 in a nationally representative sample of 4278 older adults, ≥ 50 years. Data were obtained on sociodemographic and health factors related to self-reported cataracts in older persons in Ghana. Data were analysed using descriptive measures (frequencies and proportions), chi-square test for associations in categorical outcome measures, and logistic regression for predictors of cataracts with SPSS version 21.

RESULTS

Overall prevalence of self-reported cataracts among 4278 older adults in Ghana was 5.4%. Prevalence was proportionately higher for women (5.9%) than men (4.7%). Reported cataracts increased with age, among urban residents, in older adults living without partners and among those with the worse life satisfaction index. Older adults in lower income groups, poorly educated or living alone had difficulty seeking vision care services. Prevalence was 8.4% among persons with diabetes, 10.4% among hypertensives and 11.4% in persons with previous history of stroke. Among older persons who had ever used alcohol or tobacco, prevalence rates of reported cataracts were 5.7% and 4.9%, respectively. Logistic regression analysis indicated that increasing age, lower income status and self-reported hypertension were significantly associated with cataract among older adults in Ghana.

CONCLUSIONS

Cataract is prevalent in older people in Ghana with approximately 1 in 20 people aged 50 years or older reporting a previous diagnosis of cataract. As cataract surgery is restorative, a public health approach on behavioural modification, well structured national outreach eye care services (for rural residents), inclusion of basic eye health services at sub-district levels, increased family support and national health insurance for older persons is indicated.

Epidemiology of glaucoma in sub-saharan Africa: prevalence, incidence and risk factors

PURPOSE

The purpose of this study is to review the epidemiology of different types of glaucoma relevant to Sub-Saharan Africa (SSA) and to discuss the evidence regarding the risk factors for onset and progression of glaucoma, including risk factors for glaucoma blindness.

METHODS

Electronic databases (PubMed, MedLine, African Journals Online- AJOL) were searched using the full text, Medical Subject Headings (MeSH) terms, author(s) and title to identify publications since 1982 in the following areas: population-based glaucoma prevalence and incidence studies in SSA and in African-derived black populations outside Africa; population-based prevalence and incidence of blindness and visual impairment studies in SSA including rapid assessment methods, which elucidate the glaucoma-specific blindness prevalence; studies of risk factors for glaucoma; and publications that discussed public health approaches for the control of glaucoma in Africa.

RESULTS

Studies highlighted that glaucoma in SSA is a public health problem and predominantly open-angle glaucoma. It is the second-leading cause of blindness, has a high prevalence, an early onset and progresses more rapidly than in Caucasians. These factors are further compounded by poor awareness and low knowledge about glaucoma even by persons affected by the condition.

CONCLUSION

Glaucoma care needs to be given high priority in Vision 2020 programs in Africa. Many questions remain unanswered and there is a need for further research in glaucoma in SSA in all aspects especially epidemiology and clinical care and outcomes involving randomized controlled trials. Genetic and genome-wide association studies may aid identification of high-risk groups. Social sciences and qualitative studies, health economics and health systems research will also enhance public health approaches for the prevention of blindness due to glaucoma.

Blindness and visual impairment in an urban West African population: the Tema Eye Survey

OBJECTIVE

To determine the prevalence, causes, and risk factors of blindness and visual impairment among persons aged 40 years or older residing in an urban West African location.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

A total of 5603 participants residing in Tema, Ghana.

METHODS

Proportionate random cluster sampling was used to select participants aged 40 years or older living in the city of Tema. Presenting distance visual acuity (VA) was measured at 4 and 1 m using a reduced logarithm of the minimum angle of resolution tumbling E chart and then with trial frame based on autorefraction. A screening examination was performed in the field on all participants. Complete clinical examination by an ophthalmologist was performed on participants with best-corrected visual acuity (BCVA) <20/40 or failure of any screening test.

MAIN OUTCOME MEASURES

Age- and gender-specific prevalence, causes, and risk factors for blindness (VA of <20/400 in the better eye, World Health Organization definition) and visual impairment (VA of <20/40 in the better eye).

RESULTS

A total of 6806 eligible participants were identified, of whom 5603 (82.3%) participated in the study. The mean age (± standard deviation) of participants was 52.7 ± 1 0.9 years. The prevalence of visual impairment and blindness was 17.1% and 1.2%, respectively. After refraction and spectacle correction, the prevalence of visual impairment and blindness decreased to 6.7% and 0.75%, respectively, suggesting that refractive error is the major correctable cause of visual impairment and blindness in this population. Of 65 subjects with a VA <20/400, 22 (34%) were correctable with refraction, 21 to the level of visual impairment and 1 to normal. The remaining 43 patients (66%) had underlying pathology (cataract in 19, glaucoma in 9, nonglaucomatous optic neuropathy in 3, corneal opacities in 3, retinal disease in 3, and undetermined in 5) that prevented refractive correction. Increased age was a significant risk factor for blindness and visual impairment.

CONCLUSIONS

There is a high prevalence of blindness and visual impairment among those aged ≥ 40 years in Tema, Ghana, West Africa. Refractive error is a major cause of blindness and visual impairment in this population, followed by cataract, glaucoma, and corneal disease.

Prevalence of blindness in people over 40 years in the volta region of ghana

SummaryIn 2001, we conducted a population-based cluster survey of the prevalence of blindness and glaucoma in three districts of the Volta region of Ghana, West Africa. A secondary purpose was to assess the presenting visual acuities of individuals who had undergone extracapsular cataract extraction with an intraocular lens implant (ECCE/IOL) and intracapsular cataract extraction (ICCE). The target population consisted of 2400 adults, aged 40 years and older, of whom, 2298 (95.7%) were examined. The prevalence of moderate to severe bilateral blindness was found to be 4.4 %. The main causes of blindness were cataract and glaucoma (53.9% and 20.6%, respectively). Eighty-one percent of the blind had preventable or treatable causes. Nine percent of the population >/=40 years needed cataract surgery in one or both eyes for vision </=6/18. The corrected prevalence of glaucoma in one or both eyes was 7.5%. There were 51 individuals who had undergone cataract surgery, all of whom had been operated in Ghana. Those who had ECCE/IOL surgery had a presenting visual acuity of 20/60 or better in 65% of eyes while those who had ICCE surgery achieved this level in only 30% of eyes [p=0.02].

National Registry for the Blind in Israel: Estimation of prevalence and incidence rates and causes of blindness

OBJECTIVE

To describe the population registered as blind in Israel and estimate the prevalence and incidence of blindness, by age, sex and the causes of blindness.

METHODS

Israel has maintained a Registry for the Blind since 1987. Patients are identified by ophthalmologists and registered if they have a visual acuity of < or = 0.05 (20/400) or a visual field of < 20 degrees radius in their better eye. The Registry consists of all eligible citizens living in Israel at the time of registration. This report includes prevalence data on 18,891 persons enrolled in the Registry from 1987-1999 and still alive and living in Israel in 1999, and incidence data on 2,511 persons newly registered in 1999. Data were collected on visual acuity and visual field loss, cause of blindness, and patient demographics.

RESULTS

In 1999, the estimated prevalence rate of blindness nationwide was 0.31% and the estimated incidence rate was 0.037%. The major causes of blindness in the complete Registry were age related macular degeneration (AMD) and glaucoma (14%), followed by diabetic retinopathy (11%), cataract and myopic maculopathy (10%), and optic atrophy (8.4%). The leading causes of newly diagnosed blindness were age-related macular degeneration (AMD) (20%), glaucoma (14%), diabetic retinopathy (12%), myopic maculopathy (11%), and optic atrophy and cataract (10%).

CONCLUSIONS

Israel has one of the few nationwide blindness registries in the world. The prevalence and incidence of blindness in Israel appear to be comparable to other western countries. Comparisons are difficult because of different definitions of blindness, age distributions, and the uniqueness of the Israeli Registry.

Prevalence and causes of blindness and visual impairment in Muyuka: a rural health district in South West Province, Cameroon

AIM

To estimate the prevalence and causes of blindness and visual impairment in the population aged 40 years and over in Muyuka, a rural district in the South West Province of Cameroon.

METHODS

A multistage cluster random sampling methodology was used to select 20 clusters of 100 people each. In each cluster households were randomly selected and all eligible people had their visual acuity (VA) measured by an ophthalmic nurse. Those with VA <6/18 were examined by an ophthalmologist.

RESULTS

1787 people were examined (response rate 89.3%). The prevalence of binocular blindness was 1.6% (95% CI: 0.8% to 2.4%), 2.2% (1.% to 3.1%) for binocular severe visual impairment, and 6.4% (5.0% to 7.8%) for binocular visual impairment. Cataract was the main cause of blindness (62.1%), severe visual impairment (65.0%), and visual impairment (40.0%). Refractive error was an important cause of severe visual impairment (15.0%) and visual impairment (22.5%). The cataract surgical coverage for people was 55% at the <3/60 level and 33% at the <6/60 level. 64.3% of eyes operated for cataract had poor visual outcome (presenting VA<6/60).

CONCLUSIONS

Strategies should be developed to make cataract services affordable and accessible to the population in the rural areas. There is an urgent need to improve the outcome of cataract surgery. Refractive error services should be provided at the community level.

Prevalence and causes of visual field loss as determined by frequency doubling perimetry in urban and rural adult Chinese

PURPOSE

To determine prevalence and causes of visual field loss (VFL) as determined by frequency doubling perimetry in elderly Chinese individuals.

DESIGN

Population-based, cross-sectional cohort study.

METHODS

The Beijing Eye Study included 4439 of 5324 subjects (83.4%) who were invited to participate with an age of 40+ years. Visual field was assessed by frequency doubling threshold perimetry. Main outcome measure was an abnormal visual field defined as at least one test location of reduced sensitivity.

RESULTS

Of the 4439 people who were examined, 4350 subjects (98.0%; 8617 eyes) provided measurement data by frequency doubling perimetry. In subjects aged 40 to 49 years, the most frequent cause for VFL was degenerative myopia followed by glaucoma, other optic nerve diseases, and cataract. In the subjects aged 60 to 69 years, the most frequent cause for VFL was cataract, followed by glaucoma and degenerative myopia. In the subjects aged 70+ years, the most frequent cause for VFL was glaucoma, followed by cataract and degenerative myopia. VFL was associated significantly with age (P < .001), myopic refractive error (P < .001), rural region (P = .001), low level of education (P = .01), degree of nuclear cataract (P < .001), and intraocular pressure (P < .001).

CONCLUSION

In contrast to Western countries, age-related macular degeneration and diabetic retinopathy play a minor role as a cause for VFL in China.

Visual loss in urban and rural chronic glaucoma patients in Ghana

The visual acuity of newly diagnosed glaucoma patients in a rural and an urban area were compared in a hospital-based cross-sectional study in Ghana. Age at presentation was strikingly higher in the rural group due to local factors which result in a difference-in-age structure of the rural and urban population. The crude relative frequency of bilateral blindness was significantly higher for rural than urban. However, with age adjusted relative frequencies for bilateral blindness there was no significant difference between rural and urban patients. There was significant difference between them for those aged 51-71 when blindness in one or both eyes were considered together. There was more consistent blindness in the rural community: the difference was attributed to local factors such as better access to eye care in the urban group.

Survey of blindness and visual impairment in Bioko, Equatorial Guinea

AIMS

This study was designed to estimate the prevalence of blindness and its main aetiologies in Bioko, an onchocerciasis endemic zone of Equatorial Guinea.

METHODS

Random sampling was applied, proportionally to population distribution into urban or rural areas. All the subjects underwent a basic eye examination by trained nurses. In the presence of any ocular affection or a visual acuity of less than 0.3, the subject was visited by the ophthalmologist. This visit included direct and indirect ophthalmoscopy, anterior segment examination with a slit lamp, and intraocular pressure recording. Blindness and visual impairment were defined by using the WHO criteria.

RESULTS

3218 subjects were screened, with a mean age of 34.1 (SD 21.6) years, ranging from 1 month to 102 years (median 34 years). The overall prevalence of blindness was 3.2% (95% CI: 2.6% to 3.9%). Unilateral blindness was present in 4.2%. Visual impairment was diagnosed in 200 patients (6.8%). More than 20% of the acuities inferior to 0.7 improved when explored with a pinhole. The main causes of blindness were cataracts (61.3%); macular affection (25.3%), optic atrophy (16%), and glaucoma (13.3%). Ocular onchocerciasis was detected in 12 cases (0.4%).

CONCLUSION

Ocular onchocerciasis was very uncommon in an area of high endemicity. Results also pointed at the lack of basic ophthalmologist eye care and optician resources in the island.

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.

Intraocular pressure and gonioscopic findings in rural communities mesoendemic and nonendemic for onchoceriasis, Kaduna State, Nigeria

PURPOSE

To report on glaucoma-related ocular parameters, namely intraocular pressure and peripheral anterior synechiae, in the presence of onchocercal infection.

METHODS

Two computer-generated random samples of individuals were drawn from communities mesoendemic and nonendemic for onchocerciasis respectively. Applanation tonometry and gonioscopy were carried out on these individuals.

RESULTS

Four hundred and thirty-six and 319 individuals from the mesoendemic and nonendemic communities were examined respectively. The mean intraocular pressure was 1.58 mmHg lower in the individuals from the mesoendemic communities compared with those from the nonendemic communities (p < 0.001) despite the prevalence of peripheral anterior synechiae being higher in the mesoendemic communities. In these communities, there was strong evidence that the prevalence of peripheral anterior synechiae increased with increasing microfilarial load.

CONCLUSIONS

Onchocercal infection produces a low-grade inflammatory process, which may result in a lowering of intraocular pressure despite the formation of peripheral anterior synechiae. Glaucomatous optic nerve damage may therefore not be the primary cause of visual loss in ocular onchocerciasis as this occurs late and is probably preceded by other blinding onchocercal pathology.

Blindness in Africa: present situation and future needs

AIM

To review the prevalence and causes of blindness in sub-Saharan Africa, the existing services and limitations, and the Vision 2020 goals for the future.

METHODS

Methodologically sound population based surveys published in the past 20 years are reviewed and results for prevalence and causes of blindness are tabulated. The current resources and needs according to recent publications and international working groups are described.

CONCLUSIONS

Blindness prevalence rates vary widely but the evidence suggests that approximately 1% of Africans are blind. The major cause is cataract; trachoma and glaucoma are also important causes of blindness. The bulk of blindness in the region is preventable or curable. Efforts should focus on eye problems which are universally present and for which there are cost effective remedies, such as cataract and refractive problems and on those problems which occur focally and can be prevented by primary healthcare measures, such as trachoma, onchocerciasis, and vitamin A deficiency. Major development of staffing levels, infrastructure, and community programmes will be necessary to achieve Vision 2020 goals.

Gender and blindness: a meta-analysis of population-based prevalence surveys

BACKGROUND

Many individual surveys of blindness have reported slightly higher rates of blindness for women. In order to gain a continent-by-continent and global sense of the burden of blindness by sex we conducted a meta-analysis of published, population-based surveys of blindness.

METHOD

Published reports were collected using a predetermined search protocol involving commercial electronic databases, hand-searching of references and direct contact with researchers. Studies were included that were population-based, included clinical examination and had a minimum sample size of 1000. The studies were critically appraised to determine methodological rigour. Data were analysed using the Cochrane Collaboration Review Manager.

RESULTS

The overall odds ratio (age-adjusted) of blind women to men is 1.43 (95% CI 1.33-1.53), ranging from 1.39 (95% CI 1.20-1.61) in Africa, 1.41 (95% CI 1.29-1.54) in Asia, and 1.63 (95% CI 1.30-2.05) in industrialised countries. There was good homogeneity of findings from Africa, Asia, and the industrialised countries. Globally, women bear excess blindness compared to men. In these surveys, overall, women account for 64.5% of all blind people. The excess of blindness in women was marked among the elderly and not due only to differential life expectancy.

CONCLUSION

The excess burden of blindness among women is likely due to a number of factors, which are different in industrialised countries compared to developing countries. Particular attention to gender differences in blindness is needed in the creation of targets for blindness reduction and in the development of interventions.

Nutrition and the eye

The topic "nutrition and the eye" cannot adequately be covered in a single review article; indeed, dozens of books and hundreds of articles have been written on the subject. This review concentrates on three areas in which specific nutrients are known or theorized to have a major impact on vision and the visual system: vitamin A deficiency; antioxidants and their proposed role in the prevention of age-related cataract and macular degeneration; and nutritional optic neuropathies, including those of the recent Cuban epidemic. In addition, this article touches on nutritional treatments that have been suggested for several less common eye diseases and, finally, considers several less prevalent conditions in which deficiency of or excess exposure to a particular nutrient has been associated with ocular pathology.

Prevalence and causes of low vision and blindness in the Extreme North Province of Cameroon, West Africa

A survey to determine the prevalence and causes of blindness and visual impairment in the Extreme North Province of Cameroon was conducted in the Spring of 1992. A total of 10,647 people age 6 years and older was selected from a multi-stage, clustered sample stratified by ecological zone. The subjects were examined by ophthalmologist-led teams for visual acuity and ocular diseases. Approximately 1.2% of the sample was bilaterally blind by the World Health Organization classification (Category 3) of vision less than the ability to count fingers at 3 meters. Similarly to results found in other developing countries, senile cataract was the most common diagnosis encountered and the most frequent principal cause of low vision and blindness.