Portable devices for diagnosis and monitoring of glaucoma: a scoping review protocol

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness in the world. The need to diagnose glaucoma early in its natural history before extensive sight loss occurs cannot be overemphasised. However, glaucoma is largely asymptomatic in the early stages of the disease making it complex to diagnose clinically and requires the support of technology. The objective of this scoping review is to determine the nature and extent of the evidence for use of portable devices in the diagnosis of glaucoma.

METHODS

We will consider studies conducted in all healthcare settings using portable devices for the detection of all type of adult glaucoma. We will also include any systematic reviews or scoping reviews, which relate to this topic. Searches will be conducted in MEDLINE, Embase, CENTRAL on the Cochrane Library and Global Health databases, from their inception to the present. Reference lists from publications identified in the searches will also be reviewed. Two authors will independently screen titles and abstracts, followed by full-text screening to assess studies for inclusion. Any disagreements will be discussed and resolved with a third author. Tables accompanied by narrative descriptions will be employed to discuss results and show how it relates to review questions.

ETHICS AND DISSEMINATION

Ethical approval is not required in this review. Only published and publicly accessible data will be used. We will publish our findings in an open-access, peer-reviewed journal and develop an accessible summary of results and recommendations.

Population health outcomes in Nigeria compared with other west African countries, 1998-2019: a systematic analysis for the Global Burden of Disease Study

BACKGROUND

Population-level health and mortality data are crucial for evidence-informed policy but scarce in Nigeria. To fill this gap, we undertook a comprehensive assessment of the burden of disease in Nigeria and compared outcomes to other west African countries.

METHODS

In this systematic analysis, using data and results of the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, we analysed patterns of mortality, years of life lost (YLLs), years lived with disability (YLDs), life expectancy, healthy life expectancy (HALE), and health system coverage for Nigeria and 15 other west African countries by gender in 1998 and 2019. Estimates of all-age and age-standardised disability-adjusted life-years for 369 diseases and injuries and 87 risk factors are presented for Nigeria. Health expenditure per person and gross domestic product were extracted from the World Bank repository.

FINDINGS

Between 1998 and 2019, life expectancy and HALE increased in Nigeria by 18% to 64·3 years (95% uncertainty interval [UI] 62·2-66·6), mortality reduced for all age groups for both male and female individuals, and health expenditure per person increased from the 11th to third highest in west Africa by 2018 (US$18·6 in 2001 to $83·75 in 2018). Nonetheless, relative outcomes remained poor; Nigeria ranked sixth in west Africa for age-standardised mortality, seventh for HALE, tenth for YLLs, 12th for health system coverage, and 14th for YLDs in 2019. Malaria (5176·3 YLLs per 100 000 people, 95% UI 2464·0-9591·1) and neonatal disorders (4818·8 YLLs per 100 000, 3865·9-6064·2) were the leading causes of YLLs in Nigeria in 2019. Nigeria had the fourth-highest under-five mortality rate for male individuals (2491·8 deaths per 100 000, 95% UI 1986·1-3140·1) and female individuals (2117·7 deaths per 100 000, 1756·7-2569·1), but among the lowest mortality for men older than 55 years. There was evidence of a growing non-communicable disease burden facing older Nigerians.

INTERPRETATION

Health outcomes remain poor in Nigeria despite higher expenditure since 2001. Better outcomes in countries with equivalent or lower health expenditure suggest health system strengthening and targeted intervention to address unsafe water sources, poor sanitation, malnutrition, and exposure to air pollution could substantially improve population health.

FUNDING

The Bill & Melinda Gates Foundation.

Grand Challenges in global eye health: a global prioritisation process using Delphi method

BACKGROUND

We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations.

METHODS

Drawing on methods used in previous Grand Challenges studies, we used a multi-step recruitment strategy to assemble a diverse panel of individuals from a range of disciplines relevant to global eye health from all regions globally to participate in a three-round, online, Delphi-like, prioritisation process to nominate and rank challenges in global eye health. Through this process, we developed both global and regional priority lists.

FINDINGS

Between Sept 1 and Dec 12, 2019, 470 individuals complete round 1 of the process, of whom 336 completed all three rounds (round 2 between Feb 26 and March 18, 2020, and round 3 between April 2 and April 25, 2020) 156 (46%) of 336 were women, 180 (54%) were men. The proportion of participants who worked in each region ranged from 104 (31%) in sub-Saharan Africa to 21 (6%) in central Europe, eastern Europe, and in central Asia. Of 85 unique challenges identified after round 1, 16 challenges were prioritised at the global level; six focused on detection and treatment of conditions (cataract, refractive error, glaucoma, diabetic retinopathy, services for children and screening for early detection), two focused on addressing shortages in human resource capacity, five on other health service and policy factors (including strengthening policies, integration, health information systems, and budget allocation), and three on improving access to care and promoting equity.

INTERPRETATION

This list of Grand Challenges serves as a starting point for immediate action by funders to guide investment in research and innovation in eye health. It challenges researchers, clinicians, and policy makers to build collaborations to address specific challenges.

FUNDING

The Queen Elizabeth Diamond Jubilee Trust, Moorfields Eye Charity, National Institute for Health Research Moorfields Biomedical Research Centre, Wellcome Trust, Sightsavers, The Fred Hollows Foundation, The Seva Foundation, British Council for the Prevention of Blindness, and Christian Blind Mission.

TRANSLATIONS

For the French, Spanish, Chinese, Portuguese, Arabic and Persian translations of the abstract see Supplementary Materials section.

Technical capacities needed to implement the WHO's primary eye care package for Africa: results of a Delphi process

OBJECTIVE

The aim of the study was to establish the technical capacities needed to deliver the WHO African Region's primary eye care package in primary healthcare facilities.

DESIGN

A two-round Delphi exercise was used to obtain expert consensus on the technical complexity of each component of the package and the technical capacities needed to deliver them using Gericke's framework of technical feasibility. The panel comprised nine eyecare experts in primary eyecare in sub-Saharan Africa. In each round panel members used a 4-point Likert scale to indicate their level of agreement. Consensus was predefined as ≥70% agreement on each statement. For round 1, statements on technical complexity were identified through a literature search of primary eyecare in sub-Saharan Africa from January 1980 to April 2018. Statements for which consensus was achieved were included in round 2, and the technical capacities were agreed.

RESULTS

Technical complexity statements were classified into four broad categories: intervention characteristics, delivery characteristics, government capacity requirements and usage characteristics. 34 of the 38 (89%) statements on health promotion and 40 of the 43 (93%) statements on facility case management were considered necessary technical capacities for implementation.

CONCLUSION

This study establishes the technical capacities needed to implement the WHO Africa Office primary eye care package, which may be generalisable to countries in sub-Saharan Africa.

Gender and ethnic diversity in global ophthalmology and optometry association leadership: a time for change

PURPOSE

To assess the diversity of leadership bodies of member organisations of the International Council of Ophthalmology (ICO) and the World Council of Optometry (WCO) in terms of: (1) the proportion who are women in all world regions, and (2) the proportion who are ethnic minority women and men in Eurocentric high-income regions.

METHODS

We undertook a cross-sectional study of board members and chairs of ICO and WCO member organisations using a desk-based assessment of member organisation websites during February and March 2020. Gender and ethnicity of board members and chairs were collected using a combination of validated algorithmic software and manual assessment, based on names and photographs where available. Gender proportions were calculated across Global Burden of Disease super-regions, and gender and ethnicity proportions in the high-income regions of Australasia, North America and Western Europe.

RESULTS

Globally, approximately one in three board members were women for both ICO (34%) and WCO (35%) members, and one in three ICO (32%) and one in five WCO (22%) chairpersons were women. Women held at least 50% of posts in only three of the 26 (12%) leadership structures assessed; these were based in Latin America and the Caribbean (59% of WCO board positions held by women, and 56% of WCO chairs), and Southeast Asia, East Asia and Oceania (55% of ICO chairs). In the Eurocentric high-income regions, white men held more than half of all board (56%) and chair (58%) positions and white women held a further quarter of positions (26% of board and 27% of chair positions). Ethnic minority women held the fewest number of board (6%) and chair (7%) positions.

CONCLUSIONS

Improvements in gender parity are needed in member organisations of the WCO and ICO across all world regions. In high-income regions, efforts to address inequity at the intersection of gender and ethnicity are also needed. Potential strategies to enable inclusive leadership must be centred on structurally enabled diversity and inclusion goals to support the professional progression of women, and people from ethnic minorities in global optometry and ophthalmology.

A situational report on low vision services in tertiary hospitals in South-East Nigeria

Background

The prevalence of functional low vision in southeast Nigeria is reportedly the highest in the country.

Aim

This study evaluated the state of low vision services and perceptions of providers and users of the service in tertiary hospitals in the region, to facilitate advocacy and planning.

Methods

This was a cross-sectional survey of available low vision services in the nine tertiary hospitals in Southeast Nigeria utilizing mixed methods. Data were collected on human resources, service delivery, and low vision equipment and devices. In-depth interviews were conducted to determine the perceptions of providers and users of the service.

Results

Varying levels of low vision services were actively provided in three of the nine hospitals surveyed. Services, equipment, and devices were suboptimally available. The three functional centers had a combined output of 61 patients seen within 6 months preceding the study and had at most two-thirds of required equipment. Low vision devices (LVDs) were available in varying degrees in only four (44%) of the hospitals. Twenty-one (7.6%) of the 278 eye care personnel had some low vision training across seven hospitals. The challenges highlighted by providers were mainly inadequate funding (infrastructure, training, and equipment), communication gaps, and bureaucracy. Poor awareness, affordability, acceptability, and accessibility of LVDs were major constraints for users.

Conclusion

Low vision services are available in some tertiary facilities in southeast Nigeria. Improved funding and better awareness of the availability of low vision services by eye care providers and the general public are needed to strengthen services.

Cataract Services are Leaving Widows Behind: Examples from National Cross-Sectional Surveys in Nigeria and Sri Lanka

The Sustainable Development Goals aim to leave no one behind. We explored the hypothesis that women without a living spouse—including those who are widowed, divorced, separated, and never married—are a vulnerable group being left behind by cataract services. Using national cross-sectional blindness surveys from Nigeria (2005–2007; n = 13,591) and Sri Lanka (2012–2014; n = 5779) we categorized women and men by marital status (married/not-married) and place of residence (urban/rural) concurrently. For each of the eight subgroups we calculated cataract blindness, cataract surgical coverage (CSC), and effective cataract surgical coverage (eCSC). Not-married women, who were predominantly widows, experienced disproportionate cataract blindness—in Nigeria they were 19% of the population yet represented 56% of those with cataract blindness; in Sri Lanka they were 18% of the population and accounted for 54% of those with cataract blindness. Not-married rural women fared worst in access to services—in Nigeria their CSC of 25.2% (95% confidence interval, CI 17.8–33.8%) was far lower than the best-off subgroup (married urban men, CSC 80.0% 95% CI 56.3–94.3); in Sri Lanka they also lagged behind (CSC 68.5% 95% CI 56.6–78.9 compared to 100% in the best-off subgroup). Service quality was also comparably poor for rural not-married women—eCSC was 8.9% (95% CI 4.5–15.4) in Nigeria and 37.0% (95% CI 26.0–49.1) in Sri Lanka. Women who are not married are a vulnerable group who experience poor access to cataract services and high cataract blindness. To “leave no one behind”, multi-faceted strategies are needed to address their needs.

The Current Status of Glaucoma and Glaucoma Care in Sub-Saharan Africa

Glaucoma is a serious and irreversibly blinding eye condition of public health importance in Africa. The absence of distinct early symptoms makes the condition hard to recognize by patients. The gradual vision deterioration that occurs is worse in one eye, thereby making it difficult for those affected to be aware of the vision loss until the advanced stages of the disease. We discuss the epidemiology of glaucoma in sub-Saharan Africa, highlighting the risk factors for the disease as well as risk factors for blindness in glaucoma patients. Available evidence suggests that treatment options of medical, surgical, and laser therapies for glaucoma are limited by availability of medicines and equipment, lack of adequate surgical and diagnostic skills, and high costs of treatment. We propose 3 complementary strategies in developing models of glaucoma care: strengthening clinical services for glaucoma; earlier detection of glaucoma in the clinics and communities; and strengthening health systems governance. Further research to define a suitable cost-beneficial treatment modality and mechanisms for financing eye care is required.

Safety and effectiveness of primary transscleral diode laser cyclophotoablation for glaucoma in Nigeria

Importance

To investigate the safety, effectiveness and follow‐up rates after transscleral diode laser cyclophotocoagulation as primary treatment for seeing eyes with primary open angle glaucoma in Bauchi, Nigeria.

Background

There is a high prevalence of primary open angle glaucoma in Africa where adherence to medical treatment and acceptance of surgery are poor.

Design

Prospective case series.

Participants

New glaucoma patients where surgical intervention was recommended.

Methods

A diode 810 nm laser G‐probe was used under retrobulbar anaesthesia to deliver approximately 20 shots for 2000 ms, titrating the power. If both eyes were treated the first was the study eye. Repeat treatment offered if the intraocular pressure (IOP) was >21 mmHg on two consecutive visits.

Main Outcome Measures

IOP < 22 mmHg, change in ≥2 lines of Snellen visual acuity (VA), and complications.

Results

201 out of 204 eyes with complete data analysed. Mean age 52 years, 17 (8.3%) eyes were re‐treated. Mean pre‐treatment IOP was 39 (SD 11) mmHg. 106 (53%) attended at 12 months when the mean IOP was 19 (7–45) mmHg; 77 (73%) had IOP < 22 mmHg. VAs were better in 13 (12.3%) and worse in 23 (21.7%) eyes. Postoperative complications included mild uveitis (5.5%), corneal oedema (2.5%), severe uveitis (0.5%) and transient hypotony (2.0%). No hypotony at 12 months.

Conclusions and Relevance

Transscleral diode laser cyclophotocoagulation controlled IOP in almost three quarters of eyes at 12 months with short‐term preservation of vision and minimal complications. Poor follow‐up in this setting highlights the need for an effective, safe and acceptable treatment where regular follow‐up is less critical.

Improving services for glaucoma care in Nigeria: implications for policy and programmes to achieve universal health coverage

Glaucoma in Africa is sometimes referred to as the silent thief of sight. In Nigeria, glaucoma is common, it is serious, ophthalmologists face many constraints in managing it, people do not even know they have it until it is advanced, patients do not understand or comply with treatment after they are diagnosed and the poor are more likely to be glaucoma blind. Available evidence indicates that the health system in Nigeria is failing to meet the needs of patients with glaucoma. Based on evidence, we propose future directions for improving services for glaucoma care in Nigeria, and the implications for policy and programmes to control glaucoma blindness, using a health system-oriented approach. Three complementary strategies are required: (i) strengthening clinical services for glaucoma-by developing models of glaucoma care, improving clinical treatment options, making medicines and equipment available, financing glaucoma care and training eye care workers; (ii) introducing initiatives for earlier detection of glaucoma in the clinic and approaches in the community and (iii) strengthening health system governance. Glaucoma is a complex disease to manage and addressing it as a public health problem is challenging. However, we need to change the paradigm to recognise that glaucoma is a potentially avoidable cause of blindness in Africa.

Poverty and blindness in Nigeria

No abstract available.

Agreement in Measurement of Optic Cup-to-Disc Ratio with Stereo Biomicroscope Funduscopy and Digital Image Analysis: Results from the Nigeria National Blindness and Visual Impairment Survey

PURPOSE

To determine agreement in estimations of vertical cup-to-disc ratio (VCDR) between clinical stereo-biomicroscopic funduscopy and digital fundus image analysis.

METHODS

Systematic sampling of 1-in-7 from a sample of 13,591 participants aged ≥40 years gave a subsample who were examined in detail. VCDR was estimated clinically by 60 diopter aspheric lens biomicroscopic funduscopy (c-VCDR) and by digital fundus images (i-VCDR) graded at the Moorfields Eye Hospital Reading Centre. Spearman's correlation coefficient, paired t-test and the Bland-Altman method to assess limits of agreement (LOA) between the two methods were applied.

RESULTS

Of 1759 participants in the subsample, 848 participants (48%) with normal frequency doubling technology (FDT) visual fields and data for i-VCDR and c-VCDR in both eyes (n = 1696 eyes) were included in the analysis. By absolute difference of VCDR values for each eye between the two methods, 1585 eyes (94%) differed by ≤0.2. Mean i-VCDR was 0.381 (standard deviation, SD 0.156), and mean c-VCDR 0.321 (SD 0.145). i-VCDRs were significantly larger by a mean difference of 0.061 (SD 0.121; 95% confidence interval, CI, 0.055-0.066; p < 0.001). The 95% LOA assessed by the Bland-Altman method were lower limit -0.182 (95% CI -0.192 to -0.172) and upper limit 0.303 (95% CI 0.293-0.313). The 95% LOA intervals narrowed with higher VCDR.

CONCLUSION

Digital image analysis and clinical assessment are two distinct methods to measure VCDR; with larger i-VCDRs in this survey. Applying i-VCDR cut-off values to c-VCDR measurements in the Nigeria Blindness Survey might have underestimated glaucoma prevalence. It is recommended that all participants in glaucoma surveys have VCDR by digital image measurement.

So let me find my way, whatever it will cost me, rather than leaving myself in darkness: experiences of glaucoma in Nigeria

BACKGROUND

Blindness from glaucoma is associated with socio-economic deprivation, presumed to reflect poor access to care and poor adherence to treatment.

OBJECTIVES

To determine why people with glaucoma are presenting late for treatment and to understand access to glaucoma care. Additionally, we sought to identify what patients and the community know, do and think about the condition and why the poor are the most affected with glaucoma blindness.

DESIGN

Study participants were from four communities and two hospitals in Abuja-FCT and Kaduna State, Nigeria. A total of 120 participants were involved, including 8 focus group discussions, 7 in-depth interviews with blind/visually impaired glaucoma patients, 5 rapid direct observation visits with these patients and 13 exit interviews of glaucoma patients in the hospital. The data were analysed using content analysis, interpreting participant experiences in terms of three key steps conceptualised as important in the care pathway: what it takes to know glaucoma, to reach a diagnosis and to access continued care.

RESULTS

This article presents multiple narratives of accessing and maintaining glaucoma care and how people manage and cope with the disease. People may be presenting late due to structural barriers, which include lack of knowledge and awareness about glaucoma and not finding an appropriately equipped health care facility. What keeps glaucoma patients within the care pathway are a good hospital experience; a support structure involving family, counselling and shared patients' experiences; and an informed choice of treatment, as well as agency. The high cost of purchasing care is a major factor for patients dropping out of treatment.

CONCLUSION

The findings suggest the need to address economic and social structural drivers as glaucoma presents another case study to demonstrate that poverty is a strong driver for blindness. There is also a need for clear glaucoma care pathways with early case finding in the community, two-way referral/feedback systems, well-equipped glaucoma care hospitals and better eye health care financing.

Ophthalmologists' practice patterns and challenges in achieving optimal management for glaucoma in Nigeria: results from a nationwide survey

PURPOSE OF THE STUDY

Glaucoma, a chronic non-communicable disease, and leading cause of irreversible blindness worldwide is a public health problem in Nigeria, with a prevalence of 5.02% in people aged ≥40 years. The purpose of this nationwide survey was to assess Nigerian ophthalmologists' practice patterns and their constraints in managing glaucoma.

STUDY DESIGN

Ophthalmologists were sent a semistructured questionnaire on how they manage glaucoma, their training in glaucoma care, where they practice, their access to equipment for diagnosis and treatment, whether they use protocols and the challenges they face in managing patients with glaucoma.

RESULTS

153/250 ophthalmologists in 80 centres completed questionnaires. Although 79% felt their training was excellent or good, 46% needed more training in glaucoma diagnosis and surgery. All had ophthalmoscopes, 93% had access to applanation tonometers, 81% to visual field analysers and 29% to laser machines (in 19 centres). 3 ophthalmologists had only ophthalmoscopes and schiøtz tonometers. For 85%, a glaucomatous optic disc was the most important feature that would prompt glaucoma work-up. Only 56% routinely performed gonioscopy and 61% used slit-lamp stereoscopic biomicroscopy for disc assessment. Trabeculectomy (with/without antimetabolites) was the only glaucoma surgery performed with one mention of canaloplasty. Poor compliance with medical treatment (78%) and low acceptance of surgery (71%) were their greatest challenges.

CONCLUSIONS

This study indicates that a systems-oriented approach is required to enhance ophthalmologist's capability for glaucoma care. Strategies to improve glaucoma management include strengthening poorly equipped centres including provision of lasers and training, and improving patients' awareness and education on glaucoma.

Poverty and Blindness in Nigeria: Results from the National Survey of Blindness and Visual Impairment

PURPOSE

Poverty can be a cause and consequence of blindness. Some causes only affect the poorest communities (e.g. trachoma), and poor individuals are less likely to access services. In low income countries, cataract blind adults have been shown to be less economically active, indicating that blindness can exacerbate poverty. This study aims to explore associations between poverty and blindness using national survey data from Nigeria.

METHODS

Participants ≥40 years were examined in 305 clusters (2005-2007). Sociodemographic information, including literacy and occupation, was obtained by interview. Presenting visual acuity (PVA) was assessed using a reduced tumbling E LogMAR chart. Full ocular examination was undertaken by experienced ophthalmologists on all with PVA <6/12 in either eye. Causes of vision loss were determined using World Health Organization guidelines. Households were categorized into three levels of poverty based on literacy and occupation at household level.

RESULTS

A total of 569/13,591 participants were blind (PVA <3/60, better eye; prevalence 4.2%, 95% confidence interval [CI] 3.8-4.6%). Prevalences of blindness were 8.5% (95% CI 7.7-9.5%), 2.5% (95% CI 2.0-3.1%), and 1.5% (95% CI 1.2-2.0%) in poorest, medium and affluent households, respectively (p = 0.001). Cause-specific prevalences of blindness from cataract, glaucoma, uncorrected aphakia and corneal opacities were significantly higher in poorer households. Cataract surgical coverage was low (37.2%), being lowest in females in poor households (25.3%). Spectacle coverage was 3 times lower in poor than affluent households (2.4% vs. 7.5%).

CONCLUSION

In Nigeria, blindness is associated with poverty, in part reflecting lower access to services. Reducing avoidable causes will not be achieved unless access to services improves, particularly for the poor and women.

A Population-based survey of the prevalence and types of glaucoma in Nigeria: results from the Nigeria National Blindness and Visual Impairment Survey

Background

Glaucoma is the leading cause of irreversible blindness worldwide. There tends to be a lower reporting of glaucoma in Africa compared to other blinding conditions in global burden data. Research findings of glaucoma in Nigeria will significantly increase our understanding of glaucoma in Nigeria, in people of the West African diaspora and similar population groups. We determined the prevalence and types of glaucoma in Nigeria from the Nigeria National Blindness and Visual Impairment cross-sectional Survey of adults aged ≥40 years.

Methods

Multistage stratified cluster random sampling with probability-proportional-to-size procedures were used to select a nationally representative sample of 15,027 persons aged ≥40 years. Participants had logMAR visual acuity measurement, FDT visual function testing, autorefraction, A-scan biometry and optic disc assessment. Participants with visual acuity of worse than 6/12 or suspicious optic discs had detailed examination including Goldmann applanation tonometry, gonioscopy and fundus photography. Disc images were graded by Moorfields Eye Hospital Reading Centre. Glaucoma was defined using International Society of Geographical and Epidemiological Ophthalmology criteria; and classified into primary open-angle or primary angle-closure or secondary glaucoma. Diagnosis of glaucoma was based on ISGEO classification. The type of glaucoma was determined by gonioscopy.

Results

A total of 13,591 participants in 305 clusters were examined (response rate 90.4 %). Optic disc grading was available for 25,289 (93 %) eyes of 13,081 (96 %) participants. There were 682 participants with glaucoma; a prevalence of 5.02 % (95 % CI 4.60–5.47). Among those with definite primary glaucoma that had gonioscopy (n = 243), open-angle glaucoma was more common (86 %) than angle-closure glaucoma (14 %). 8 % of glaucoma was secondary with the commonest causes being couching (38 %), trauma (21 %) and uveitis (19 %). Only 5.6 % (38/682) of participants with glaucoma knew they had the condition. One in every 5 persons with glaucoma (136;20 %) was blind i.e., visual acuity worse than 3/60.

Conclusion

Nigeria has a high prevalence of glaucoma which is largely open-angle glaucoma. A high proportion of those affected are blind. Secondary glaucoma was mostly as a consequence of procedures for cataract. Public health control strategies and high quality glaucoma care service will be required to reduce morbidity and blindness from glaucoma.

Multilevel Analysis of Trachomatous Trichiasis and Corneal Opacity in Nigeria: The Role of Environmental and Climatic Risk Factors on the Distribution of Disease

The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends observed across the country and more local variation within areas. Relative contributions of individual and cluster-level risk factors to the geographic distribution of disease remain largely unknown. The primary aim of this analysis is to assess the relationship between climatic factors and trachomatous trichiasis (TT) and/or corneal opacity (CO) due to trachoma in Nigeria, while accounting for the effects of individual risk factors and spatial correlation. In addition, we explore the relative importance of variation in the risk of trichiasis and/or corneal opacity (TT/CO) at different levels. Data from the 2007 National Blindness and Visual Impairment Survey were used for this analysis, which included a nationally representative sample of adults aged 40 years and above. Complete data were available from 304 clusters selected using a multi-stage stratified cluster-random sampling strategy. All participants (13,543 individuals) were interviewed and examined by an ophthalmologist for the presence or absence of TT and CO. In addition to field-collected data, remotely sensed climatic data were extracted for each cluster and used to fit Bayesian hierarchical logistic models to disease outcome. The risk of TT/CO was associated with factors at both the individual and cluster levels, with approximately 14% of the total variation attributed to the cluster level. Beyond established individual risk factors (age, gender and occupation), there was strong evidence that environmental/climatic factors at the cluster-level (lower precipitation, higher land surface temperature, higher mean annual temperature and rural classification) were also associated with a greater risk of TT/CO. This study establishes the importance of large-scale risk factors in the geographical distribution of TT/CO in Nigeria, supporting anecdotal evidence that environmental conditions are associated with increased risk in this context and highlighting their potential use in improving estimates of disease burden at large scales.

Trichiasis (TT) and corneal opacity (CO) are chronic stages of trachoma, which remains an important cause of blindness. This study used multilevel spatial models to investigate risk factors for TT/CO in Nigeria, including data for more than 13,500 adults aged 40 years and above collected in the 2007 National Blindness and Visual Impairment survey. Individual-level risk factors were consistent with those identified in other studies, including a higher risk in females, older individuals and those with lower socioeconomic status. After controlling for these factors, there was evidence that a number of environmental and climatic factors are associated with the distribution of TT/CO in Nigeria. These findings establish for the Nigerian context the importance of risk factors at different scales for the later stages of trachoma, supporting anecdotal evidence that hotter, drier environmental conditions are associated with increased risk.

Peribulbar versus retrobulbar anaesthesia for cataract surgery

BACKGROUND

Cataract is a major cause of blindness worldwide. Unless medically contraindicated, cataract surgery is usually performed under local (regional) anaesthesia. Local anaesthesia involves the blockage of a nerve subserving a given part of the body. It involves infiltration of the area around the nerve with local anaesthetic. The two main approaches in the eye are retrobulbar and peribulbar. There is debate over whether the peribulbar approach provides more effective, safer anaesthesia for cataract surgery than retrobulbar block.

OBJECTIVES

The objective of this review was to assess the effects of peribulbar anaesthesia (PB) compared to retrobulbar anaesthesia (RB) on pain scores, ocular akinesia, patient acceptability and ocular and systemic complications.

SEARCH METHODS

In the previous version of our review, we searched the databases until December 2007. In this updated version, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (March 2015); MEDLINE (1960 to March 2015); and EMBASE (1980 to March 2015).

SELECTION CRITERIA

We included randomized controlled clinical trials comparing peribulbar anaesthesia and retrobulbar anaesthesia for cataract surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted trial authors for additional information, study methodology and missing data. We carried out a descriptive narrative of results as the included studies used varied methods for reporting the outcomes. We performed a subgroup analysis for globe akinesia.

MAIN RESULTS

We included six trials involving 1438 participants. Three of the six trials had adequate sequence generation while all the trials had unclear allocation concealment There was no evidence of any difference in pain perception during surgery with either retrobulbar or peribulbar anaesthesia. Both were largely effective. There was no evidence of any difference in complete akinesia or the need for further injections of local anaesthetic. Conjunctival chemosis was more common after peribulbar block (relative risk (RR) 2.11, 95% confidence interval (CI) 1.46 to 3.05) and lid haematoma was more common after retrobulbar block (RR 0.36, 95% CI 0.15 to 0.88). Retrobulbar haemorrhage was uncommon and occurred only once, in a patient who had a retrobulbar block.

AUTHORS' CONCLUSIONS

There is little to choose between peribulbar and retrobulbar block in terms of anaesthesia and akinesia during surgery measuring acceptability to patients, need for additional injections and development of severe complications. Severe local or systemic complications were rare for both types of block.

Prevalence and risk factors for diabetes and diabetic retinopathy: results from the Nigeria national blindness and visual impairment survey

BACKGROUND

In Nigeria, urbanisation and increasing life expectancy are likely to increase the incidence of non-communicable diseases. As the epidemic of diabetes matures, visual loss from diabetic retinopathy (DR) will increase unless mechanisms for early detection and treatment improve, and health systems respond to the growing burden of non-communicable diseases.

METHODS

A nationally-representative population-based sample of 13,591 participants aged ≥40 years selected by multistage-stratified-cluster-random-sampling with probability-proportional-to-size procedures were examined in 305 clusters in Nigeria between January 2005 to June 2007. All were asked about history of diabetes and underwent basic eye examination. Visual acuity (VA) was measured using logMAR E-chart. Participants with VA<6/12 and/or DR detected underwent detailed eye examination including dilated retinal examination and retinal photography. Systematic sampling of 1-in-7 gave a subsample (n=1759) examined in detail regardless of VA; and had random blood glucose (RBG) testing. Images were graded by Moorfields Eye Hospital Reading Centre. Participants were defined as having diabetes if they were previously diagnosed or RBG>11.1mmol/l or had DR. Data in the subsample were used to estimate the prevalence and to analyse risk factors for diabetes and DR using multivariable logistic regression. Additional information on the types of DR was obtained from participants not in the subsample.

RESULTS

In the subsample, 164 participants were excluded due to missing data; and 1,595 analysed. 52/1,595 had diabetes, a prevalence of 3.3% (95%CI 2.5-4.3%); and 25/52(48%) did not know. Media opacity in 8/52 precluded retinal examination. 9/44(20.5%) had DR. Higher prevalence of diabetes was associated with urban residence (Odds ratio [OR]1.87) and overweight/obesity (OR3.02/4.43 respectively). Although not statistically significant, DR was associated with hypertension (OR3.49) and RBG>15.0mmol/L (OR8.10). Persons with diabetes had 3 times greater odds of blindness. Of 11,832 other participants in the study sample, 175(1.5%) had history of diabetes; 28 had DR. Types of DR (total=37) included 10.8% proliferative, 51.4% macular oedema.

CONCLUSION

The age-adjusted prevalence of diabetes in Nigeria was 3.25% (95%CI 2.50-4.30) and over 10% of people with diabetes aged ≥40 years had sight-threatening-DR. These data will enable the development of better public health strategies for the control of diabetes and planning services for DR to prevent vision loss.

Posterior segment eye disease in sub-Saharan Africa: review of recent population-based studies

Objective

To assess the burden of posterior segment eye diseases (PSEDs) in sub-Saharan Africa (SSA).

Methods

We reviewed published population-based data from SSA and other relevant populations on the leading PSED, specifically glaucoma, diabetic retinopathy and age-related macular degeneration, as causes of blindness and visual impairment in adults. Data were extracted from population-based studies conducted in SSA and elsewhere where relevant.

Results

PSEDs, when grouped or as individual diseases, are a major contributor to blindness and visual impairment in SSA. PSED, grouped together, was usually the second leading cause of blindness after cataract, ranging as a proportion of blindness from 13 to 37%.

Conclusions

PSEDs are likely to grow in importance as causes of visual impairment and blindness in SSA in the coming years as populations grow, age and become more urban in lifestyle. African-based cohort studies are required to help estimate present and future needs and plan services to prevent avoidable blindness.

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.

Awareness and knowledge of ocular cancers in a resource-limited economy

Aims:

To determine awareness and knowledge of ocular cancers in a resource-limited setting.

Material and Methods:

A descriptive cross-sectional survey (2009) of 1,887 Nigerians using interviewer-administered questionnaire.

Results:

Respondents were 55.6% males, and mean age was 30 years, SD 9.5. Most respondents (77.8%) had at least secondary education. Fewer respondents were aware of eye cancers (57.1%) compared to cancers in general (73.7%) (P<.001). Despite the male preponderance there were no associations between gender and awareness of ocular cancers (P=0.07) and cancers in general (P=0.85). However, education was associated with awareness of ocular cancers (P<.001) and cancers in general (P<.001). Ocular cancers were thought to be caused by corrosives 33.2%, trauma 21.4%, witchcraft 18.6%, genetic transmission 15.7%, sunlight 8.0%, radiations 2.5% and infections 0.6% (n = 883). Of 280 respondents, 41.1% based their knowledge of patients having ocular cancers on sources other than hospital diagnosis. Of 148 respondents, 16.2% were related to ‘patients’ they knew had ocular cancers. There were 202 respondents who indicated challenges to accessing orthodox medical eye care services by ocular cancer patients as high cost 55.5%, long waiting period 23.3%, long distance 15.4% and poor attitude of health workers 5.9%.

Conclusion:

Awareness of ocular cancers compared to other cancers is low. Misconceptions on the causes of ocular cancers exist. Public ocular cancers health education can enhance awareness. The need to address barriers to accessing eye care is underscored.

Review of the publications of the Nigeria national blindness survey: methodology, prevalence, causes of blindness and visual impairment and outcome of cataract surgery

This is a review of the major publications from the Nigeria national blindness survey in order to highlight major findings and challenges of eye care in Nigeria. The review summarizes methodology and key findings. Survey publications on methodology, prevalence and causes of visual impairment and outcome of cataract surgery were retrieved, reviewed and relevant data extracted, reported and discussed. The study was the largest and more detailed eye survey in Nigeria (15,375 people 40 years and older recruited). Participants had detailed eye examination including visual acuity, autorefractokeratometry, A- scan biometry, visual field and basic eye examination. Cause(s) of visual impairment in each eye using WHO algorithm was determined among participants with vision < 6/12. Some of the participants also had qualitative questions on barriers to uptake of services, quality of life and visual function. Major highlights of the results as contained in the publications include a high prevalence of blindness with 4.2% (95% CI: 3.8-4.6%;),of the study population having blindness (using presenting vision (PVA)) even with best correction the prevalence was 3.4% (95% CI: 3.0-3.8%. The prevalence of SVI using PVA was 1.5% (95% CI: 1.3-1.7%).and with best correction 0.8% (95% CI: 0.7-1.0%). Blindness varied by age groups, sex, literacy level and geopolitical zone. Furthermore, 84% of blindness was due to avoidable causes with cataract responsible for 43% of blindness, glaucoma 16.7%, uncorrected aphakia 8.4% and corneal opacity 7.9%. Of the total 538 eyes that had cataract surgery procedures, 42.7% had couching and the remaining had cataract surgery, but only 41.4% of cataract operated eyes had IOL surgery. Outcome of cataract surgery was good at presentation for only 30.8% of eyes (84 eyes) which improved to 56.8% with correction. The possible remedy for the high burden of needless blindness and harmful eye health practices in Nigeria are discussed.

The prevalence of type 2 idiopathic macular telangiectasia in two African populations

PURPOSE

Type 2 idiopathic macular telangiectasia (MacTel) is a progressive retinal disease associated with a slow deterioration of visual acuity, starting in the fifth to seventh decades of life. The etiology and pathogenesis of the disease are little known, and no effective therapy is available. We aimed to estimate the prevalence and describe the phenotype of type 2 MacTel in two African populations.

METHODS

From two population-based cross-sectional surveys conducted nationally in Nigeria and in the Nakuru district of Kenya, patients with fundus features of type 2 MacTel were selected. Diagnosis was based on color fundus images, grading performed according to the MacTel Study protocol and staged using the Gass and Blodi system. Disease phenotype and clinical characteristics of affected participants were assessed.

RESULTS

Of 8599 total participants, five showed a phenotype compatible with type 2 MacTel. Prevalence was estimated as 0.06% (95% confidence interval [CI] 0.02-0.21%) in Kenya, 0.06% (95% CI 0.01-0.17%) in Nigeria, and overall at 0.06% (95% CI 0.02-0.14%). Mean age was 62 years (SD 5 years), four of five affected participants were female, and none had a history of diabetes. Median corrected visual acuity was 6/12 in the better eye and 6/69 in the worse eye.

CONCLUSIONS

The estimated prevalence and phenotype of type 2 MacTel in the African populations examined were similar to those in predominantly white populations. All data published so far are based on the analysis of color fundus images only and are thus likely to underestimate the true prevalence of this disease.

Couching in Nigeria: prevalence, risk factors and visual acuity outcomes

PURPOSE

Couching is an ancient treatment for cataract which is still practiced in some of the poorer developing countries, particularly in sub-Saharan Africa. The purpose of this study is to describe risk factors for couching and visual acuity outcomes in a nationally representative sample of adults aged 40 years and above in Nigeria.

METHODS

Probability in proportion size methods were used to identify a representative sample. Of the 15,375 adults enumerated, 13,582 were interviewed and examined. Examination included logMar acuities, slit lamp examination and dilated fundoscopy with digital fundus imaging.

RESULTS

Almost half of the 583 eyes undergoing a procedure for cataract had been couched (249 eyes, 42.7%). Individuals living in rural areas (P = 0.033) and in the two underserved northern administrative zones (P = 0.33; P = 0.002) were more likely to have been couched. Visual outcomes were poor according to World Health Organization categories, with 55.8% of people and 73.1% of eyes having a presenting visual acuity of less than 3/60 and only 9.7% and 2.4% of people and eyes respectively having a good outcome (6/18 or better). None were wearing an aphakic correction, and with correction acuities improved but 42.6% of eyes were still blind (< 3/60).

CONCLUSIONS

Couching is still widely practiced in Nigeria and visual outcomes are very poor. The population needs to be made aware of the risks associated with the procedure, and services for high quality, affordable cataract surgery need to be expanded, particularly in rural areas and in the north of the country.

Prevalence of blindness and visual impairment in Nigeria: the National Blindness and Visual Impairment Study

PURPOSE

To determine the prevalence of blindness and visual impairment among adults aged > or = 40 years in Nigeria.

METHODS

Multistage, stratified, cluster random sampling with probability proportional to size procedures was used to identify a cross-sectional nationally representative sample of 15,027 persons > or = 40 years of age from all 36 states in Nigeria and the Federal Capital Territory. Distance visual acuity (VA) was measured with a reduced logMAR tumbling-E chart at 4 and 1 m. Presenting and best corrected visual acuities were recorded. Autorefraction was performed in all examined adults. Clinical evaluations included examination under dilation for those with presenting vision < 6/12 in either eye.

RESULTS

In the study, 15,122 persons aged > or = 40 years were enumerated and 13,599 (89.9%) examined. Prevalence of blindness (< 20/400 in the better eye) and severe visual impairment (< 20/200-20/400; presenting vision) was 4.2% (95% confidence interval [CI]: 3.8%-4.6%) and 1.5% (95% CI: 1.3%-1.7%), respectively. Blindness was associated with increasing age, being female, poor literacy, and residence in the North. Participants residing in the South West had the lowest prevalence while those in the North East had the highest prevalence of blindness. It is estimated that 4.25 million adults aged > or = 40 years have moderate to severe visual impairment or blindness (< 20/63 in the better eye).

CONCLUSIONS

There is a high prevalence of blindness and severe visual impairment among those aged > or = 40 years in Nigeria. Significant differences exist between the geopolitical zones and emphasis should be on ensuring eye services across Nigeria, which means that planning at the regional level is necessary.

The Nigerian national blindness and visual impairment survey: Rationale, objectives and detailed methodology

Background

Despite having the largest population in Africa, Nigeria has no accurate population based data to plan and evaluate eye care services. A national survey was undertaken to estimate the prevalence and determine the major causes of blindness and low vision. This paper presents the detailed methodology used during the survey.

Methods

A nationally representative sample of persons aged 40 years and above was selected. Children aged 10–15 years and individuals aged <10 or 16–39 years with visual impairment were also included if they lived in households with an eligible adult. All participants had their height, weight, and blood pressure measured followed by assessment of presenting visual acuity, refractokeratomery, A-scan ultrasonography, visual fields and best corrected visual acuity. Anterior and posterior segments of each eye were examined with a torch and direct ophthalmoscope. Participants with visual acuity of < = 6/12 in one or both eyes underwent detailed examination including applanation tonometry, dilated slit lamp biomicroscopy, lens grading and fundus photography. All those who had undergone cataract surgery were refracted and best corrected vision recorded. Causes of visual impairment by eye and for the individual were determined using a clinical algorithm recommended by the World Health Organization. In addition, 1 in 7 adults also underwent a complete work up as described for those with vision < = 6/12 for constructing a normative data base for Nigerians.

Discussion

The field work for the study was completed in 30 months over the period 2005–2007 and covered 305 clusters across the entire country. Concurrently persons 40+ years were examined to form a normative data base. Analysis of the data is currently underway.

Conclusion

The methodology used was robust and adequate to provide estimates on the prevalence and causes of blindness in Nigeria. The survey would also provide information on barriers to accessing services, quality of life of visually impaired individuals and also provide normative data for Nigerian eyes.

Peribulbar versus retrobulbar anaesthesia for cataract surgery

BACKGROUND

Cataract is a major cause of blindness worldwide. Unless medically contraindicated, cataract surgery is usually performed under local (regional) anaesthesia. Local anaesthesia involves the blockage of a nerve subserving a given part of the body by infiltration of the area around the nerve with local anaesthetic. The two main approaches in the eye are retrobulbar and peribulbar. There is debate over whether the peribulbar approach provides more effective and safer anaesthesia for cataract surgery than retrobulbar block.

OBJECTIVES

The objective of this review was to assess the effects of peribulbar anaesthesia (PB) compared to retrobulbar anaesthesia (RB) on pain scores, ocular akinesia, patient acceptability and ocular and systemic complications.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 4); MEDLINE (1960 to December 2007); and EMBASE (1980 to December 2007).

SELECTION CRITERIA

We included randomized controlled clinical trials comparing peribulbar anaesthesia and retrobulbar anaesthesia for cataract surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted trial authors for additional information, study methodology and missing data. We carried out a descriptive narrative of results as the methods used by the included stories for reporting the outcomes varied. We performed a subgroup analysis for globe akinesia.

MAIN RESULTS

We included six trials involving 1438 participants. Two of the six trials had a low risk of bias; the remaining four had a moderate risk of bias. There was no evidence of any difference in pain perception during surgery with either retrobulbar or peribulbar anaesthesia. Both were largely effective. There was no evidence of any difference in complete akinesia or the need for further injections of local anaesthetic. Conjunctival chemosis was more common after peribulbar block (relative risk (RR) 2.11, 95% confidence Interval (CI) 1.46 to 3.05) and lid haematoma was more common after retrobulbar block (RR 0.36, 95% CI 0.15 to 0.88). Retrobulbar haemorrhage was uncommon and occurred only once, in a patient who had a retrobulbar block.

AUTHORS' CONCLUSIONS

There is little to choose between peribulbar and retrobulbar block in terms of anaesthesia and akinesia during surgery in terms of acceptability to patients, need for additional injections and development of severe complications. Severe local or systemic complications were rare in PB and RB.

Vitamin A deficiency in Nigeria

Childhood blindness is second only to cataract in magnitude of world blindness when the "blind years" is considered. The "blind years" is the number of years a person lives with blindness. Studies have shown that over 34%-69% of childhood blindness in Nigeria is caused by corneal opacity, which results mainly from an interplay of vitamin A deficiency, measles and harmful traditional eye practices. However, vitamin A deficiency which manifests in the eye as xerophthalmia is the dominant problem in these children. The purpose of this review is to stress the importance of xerophthalmia, which is of public health significance, as an important cause of childhood blindness in Nigeria. Studies involving surveys of xerophthalmia, childhood and nutritional blindness are reviewed with data extracted from a nationwide survey on prevalence of xerophthalmia. The likely explanation for vitamin A deficiency in Nigerian children is discussed with possible solutions and recommendations made to control this avoidable and devastating cause of blindness.

Audit of outcome of an extracapsular cataract extraction and posterior chamber intraocular lens training course

BACKGROUND

A training course for cataract surgery with intraocular lens implantation was organised in April 1997 at the National Eye Centre, Kaduna, Nigeria. Operations were performed by six Nigerian consultant ophthalmologists under the supervision of two surgeons from Aravind Eye Hospital, India.

METHODS

A total of 175 eyes with uncomplicated cataracts were operated on after careful selection. All but six patients had extracapsular cataract extraction with posterior chamber intraocular lens insertion during the training programme.

RESULTS

The mean age of the patients at operation was 54. 2 years. One hundred and forty five of the operated eyes (85.8%) were blind before surgery of which six (3.6%) remained blind postoperatively. An uncorrected visual acuity of 6/60 or better was achieved in 87.3% eyes after surgery. Forty one patients (24.3%) were blind before surgery, two of whom (1.2%) remained blind afterwards. The most common intraoperative complication was posterior capsular rent which occurred in 10 eyes (5.7%); striate keratopathy/corneal oedema and cortical remnant were the most common immediate postoperative complications, occurring in 44.6% and 8.0%, respectively.

CONCLUSION

With adequate surgical skills, extracapsular cataract extraction with posterior chamber intraocular lens implantation offers good visual rehabilitation even under training conditions.