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

Optical Coherence Tomography Versus Optic Disc Photo Assessment in Glaucoma Screening

PRCIS

Optical coherence tomography (OCT) and optic disc photography present valuable but distinct capabilities for glaucoma screening.

OBJECTIVE

This review article examines the strengths and limitations of OCT and optic disc photography in glaucoma screening.

METHODS

A comprehensive literature review was conducted, focusing on the accuracy, feasibility, cost-effectiveness, and technological advancements in OCT and optic disc photography for glaucoma screening.

RESULTS

OCT is highly accurate and reproducible but faces limitations due to its cost and less portable nature, making widespread screening challenging. In contrast, optic disc photos are more accessible and cost-effective but are hindered by subjective interpretation and inconsistent grading reliability. A critical challenge in glaucoma screening is achieving a high PPV, particularly given the low prevalence of the disease, which can lead to a significant number of false positives. The advent of artificial intelligence (AI) and deep learning models shows potential in improving the diagnostic accuracy of optic disc photos by automating the detection of glaucomatous optic neuropathy and reducing subjectivity. However, the effectiveness of these AI models hinges on the quality of training data. Using subjective gradings as training data, will carry the limitations of human assessment into the AI system, leading to potential inaccuracies. Conversely, training AI models using objective data from OCT, such as retinal nerve fiber layer thickness, may offer a promising direction.

CONCLUSION

Both OCT and optic disc photography present valuable but distinct capabilities for glaucoma screening. An approach integrating AI technology might be key in optimizing these methods for effective, large-scale screening programs.

Epidemiology and trends in the uptake of refractive error services in Harare, Zimbabwe: a hospital-based retrospective study

Aim

The study aimed to determine the epidemiology and evaluate the trends in the uptake of refractive error services in Harare.

Methods

A clinic-based retrospective study at the Greenwood Park Eye Centre and its three subsidiaries was conducted from January 1, 2015 to December 31, 2020.

Results

12,216 patients' records were retrieved, out of which 1074 (8.79%) had refractive error cases. The prevalence of visual impairment at presentation was 5.80% [95% CI: 5.39 - 6.23]. Among those with refractive error, the sample prevalence of visual impairment before correction was 41.30% [CI: 38.3 - 44.3, 95%], and 2.20% [95% CI: 1.4 - 3.3] after correction. There was inconsistency in the percentage utilization of refractive error services, with the highest being 42.60% in 2015. Refractive error types were related to age, employment position, and type of visual impairment prior to refractive error treatment.

Conclusion

There was a low percentage of refractive error services uptake in urban Zimbabwe.

The burden of visual impairment among Ethiopian adult population: Systematic review and meta-analysis

BACKGROUND

Visual impairment is a public health problem in both developing and developed countries, especially, in developing countries where most visually impaired communities are found. Knowledge of the pooled prevalence of visual impairment among adults is useful in planning, preventive programs and the provision of eye-care services for communities.

METHODS

Original observational studies published in English were included in this systematic review and meta-analysis. Eleven studies with a total sample size of 8,161 study participants were included. PubMed/Medline, HINARI, Google Scholar, Cochrane library, Web of Science, and African Journals Online databases were used to search for published articles. Data were extracted on a Microsoft Excel spreadsheet and analyzed using Revman 5.4.1 Software. Meta-analysis of further pooled prevalence estimates using the inverse variance heterogeneity model. The pooled estimate of visual impairment in the current review was estimated using a random-effects model. Forest plots were used to illustrate heterogeneity and to quantify the pooled prevalence of visual impairment. Publication bias was assessed using funnel plots. Visual impairment was defined as a presenting visual acuity of less than 6/18 in the betting-seen eye.

RESULTS

A total of 538 studies were identified from several Databases and digital libraries, of which eleven articles were selected for the final meta-analysis. Significant heterogeneity was observed across studies, suggesting a random-effects model to estimate the pooled prevalence of visual impairment. The prevalence of visual impairment in Ethiopia ranges from 10.3% in Addis Ababa central Ethiopia to 37.58% in the Northern Ethiopia. The pooled prevalence of visual impairment in the current review was 22% (95% CI: 17%-27%; I2 = 97%) using a random-effects model. There was also evidence of symmetry in the funnel plots.

CONCLUSION

This systematic review and meta-analysis demonstrated a greater burden of visual impairment among Ethiopians in various study populations. Further, intervention strategies are required to reduce the burden of visual impairment and improve quality of life.

Association between statin use and the risks of glaucoma in Australia: a 10-year cohort study

SYNOPSIS

In a cohort of middle-aged and elderly Australians, we found that long-term statin use was associated with a higher risk of glaucoma onset. As to subtypes of statins, the increased risk was only found in rosuvastatin users.

PURPOSE

To investigate the relationship between statin use and glaucoma onset in a 10-year longitudinal study.

METHODS

This nested case-control study was based on data from a large-scale cohort of Australians aged over 45 years old. Medication exposure was identified by claims records from the Pharmaceutical Benefits Scheme during the follow-up period (2009-2016). The onset of glaucoma was defined as the people with at least three claims of antiglaucoma medications. Controls matched by age, gender and cardiovascular diseases were selected from participants without prescription of antiglaucoma medications. A conditional logistic regression model was used to assess the association between statin use and glaucoma onset.

RESULTS

The proportion of statin users was higher in the case group (40.5%) than that in the control group (38.4%). After adjusting for baseline characteristics and longitudinal claims records, statin use was not associated with glaucoma onset (OR 1.04, 95% CI 0.97 to 1.11). However, an increased risk of glaucoma onset was observed in participants with a longer duration of statin use (>3 years vs <1 year: OR 1.12, 95% CI 1.04 to 1.21). With respect to specific types of statins, participants taking rosuvastatin were more likely to suffer from glaucoma (OR 1.11, 95%CI 1.01 to 1.22). The use of other statins was not significantly associated with glaucoma onset.

CONCLUSIONS

Long-term statin use was found to be associated with a higher risk of glaucoma onset in this study. Regarding specific types of statins, the increased risk of glaucoma onset was only observed in users of rosuvastatin.

Prevalence and patterns of refractive error among adults in Sagamu, South-West Nigeria

Background: The study was part of community-based research towards strengthening the provision of optical services within a local governmental area in Nigeria.Aim: To describe the prevalence of refractive errors in the southwestern Nigerian adult population.Setting: Adults of age 30 years and above who were regular residents of the local governmental area.Methods: A multistage stratified random cluster sampling method was used to select the subjects. The sampling unit was the different households. A random sample of them were refracted and then refractive errors were analysed. Analyses excluded participants with history of cataract surgery. Associations with myopia (−0.50 dioptres [D] or more) and hyperopia (≥ 0.50 D) were evaluated in logistic regression analyses.Results: The prevalence of refractive error in the study sample was 33.8% (95% confidence level [CI]: 27.1–34.4) using study participants with 6/9 presenting visual acuity but improvement by at least a line with pin hole. The prevalence of hyperopia was 46.9% and higher in women (51.8%), while that of myopia was 21.9% but higher in men (25.0%). The prevalence of hyperopia increased from 29% for 40–49 years of age to 65% for 50–59 years of age and tended to decline thereafter. Prevalence of myopia decreased from 17% in persons 40–49 years of age to 11% in those 50–59 years of age but increased after 60 years of age. A higher prevalence of myopia was positively associated (p  0.05) with lifetime occupations requiring near work, nuclear opacities, posterior subcapsular opacities and glaucoma. Factors associated with hyperopia were the same as for myopia, except for occupation, and in the opposite direction.Conclusion: The high prevalence of refractive errors strongly supports the need for an affordable and accessible optical service in the local government.

Incidence of Glaucoma Progression and Rate of Visual Field Deterioration in a Cohort of Urban Ghanaians

PRCIS

The annual incidence of glaucoma progression (9.7%) and rates of visual field mean deviation (MD) change in progressors (-1.02±0.06 dB/y) are high in a small cohort of urban Ghanaians.

PURPOSE

To report the incidence of glaucoma progression and the rate of visual field deterioration in a small cohort of Ghanaians.

METHODS

One hundred ten subjects (204 eyes) diagnosed with glaucoma at a baseline population-based screening examination were re-examined a mean of 8.3±0.8 years later. Eyes were classified as having progressed if the optic disc alone, visual field alone or both showed significant glaucomatous changes on follow-up. Visual field MD was used to calculate the rate of visual field progression.

RESULTS

Progression was observed in 89 (80.9%, 9.7%/year) subjects (130 eyes). Progression occurred in 32 (31.7%, 3.8%/year) subjects by optic disc alone (46 eyes), 38 (44.7%, 5.4%/year) subjects by visual field alone (58 eyes), and 19 (25.0%, 3.0%/year) subjects by both modalities (26 eyes). The average rate of change in MD differed significantly between progressors (-1.02±1.06 dB/y) and nonprogressors (+0.089±0.49 dB/y), P =0.001. The rate of visual field worsening was greater among those who were classified as having progressed by both structure and function (-1.29±0.68 dB/y) and by function alone (-1.21±1.20 dB/y) than by structure alone (-0.55±0.76 dB/y). Progression was significantly associated with older age [odds ratio (OR), 1.42; P <0.001] and higher baseline intraocular pressure (OR, 1.18; P =0.002). Factors associated with rate of MD change were baseline older age (OR, 1.66; P =0.003), higher intraocular pressure (OR, 2.81; P =0.007), better visual field MD (OR, 1.41; P =0.004), and systemic hypertension (OR, 1.15; P =0.029).

CONCLUSION

The incidence and rate of visual field progression are high in this longitudinal study of Ghanaian subjects with glaucoma. The findings may have important clinical and public health policy ramifications.

Estimating need and coverage for five priority assistive products: a systematic review of global population-based research

INTRODUCTION

To improve access to assistive products (APs) globally, data must be available to inform evidence-based decision-making, policy development and evaluation, and market-shaping interventions.

METHODS

This systematic review was undertaken to identify studies presenting population-based estimates of need and coverage for five APs (hearing aids, limb prostheses, wheelchairs, glasses and personal digital assistants) grouped by four functional domains (hearing, mobility, vision and cognition).

RESULTS

Data including 656 AP access indicators were extracted from 207 studies, most of which (n=199, 96%) were cross-sectional, either collecting primary (n=167) or using secondary (n=32) data. There was considerable heterogeneity in assessment approaches used and how AP indicators were reported; over half (n=110) used a combination of clinical and self-reported assessment data. Of 35 studies reporting AP use out of all people with functional difficulty in the corresponding functional domains, the proportions ranged from 4.5% to 47.0% for hearing aids, from 0.9% to 17.6% for mobility devices, and from 0.1% to 86.6% for near and distance glasses. Studies reporting AP need indicators demonstrated >60% unmet need for each of the five APs in most settings.

CONCLUSION

Variation in definitions of indicators of AP access have likely led to overestimates/underestimates of need and coverage, particularly, where the relationship between functioning difficulty and the need for an AP is complex. This review demonstrates high unmet need for APs globally, due in part to disparate data across this sector, and emphasises the need to standardise AP data collection and reporting strategies to provide a comparable evidence base to improve access to APs.

[Overview of visual impairment at the Yalgado Ouédraogo University Medical Center: Study of 501 cases]

OBJECTIVE

To determine the main causes of visual impairment according to age in patients admitted to the ophthalmology department.

MATERIALS AND METHODS

This was a retrospective study of 501 cases of visual impairment. Included were patients of both sexes whose best-corrected visual acuity in the better eye was strictly less than 5/10. The parameters studied were age, gender, place of residence, corrected visual acuity in the better eye, and diagnosis. The data were entered and processed with the Epi info 7.2 software.

RESULTS

Subjects over 50 were the most prevalent (48.5%). In patients over 50 years of age, cataracts (54.32%) were the leading cause of visual impairment, followed by glaucoma (24.69%) and non-glaucomatous optic neuropathy (26.19%). Trauma (17.62%) was frequently found in patients aged 16 to 50 years. Tropical endemic limbo-conjunctivitis (25.00%) was the leading cause of visual impairment in subjects aged 5 to 15 years.

CONCLUSION

This study confirms the results of the literature, which have shown that cataracts are the leading cause of visual impairment in developing countries. A major effort to raise awareness, provide information and therapeutic care would reduce the incidence of visual impairment.

Nutrition knowledge and dietary patterns in ophthalmic patients

CLINICAL SIGNIFICANCE

Ophthalmic nutrition education programs and good dietary patterns are of considerable significance to ocular health outcomes.

BACKGROUND

The study aimed at assessing the level of ophthalmic nutrition knowledge and to compare the dietary patterns between different ophthalmic patients.

METHODS

Four hundred and ninety-two adults (mean age 54.7 ± 19.4-years) receiving care at three eye-care facilities in Ghana were surveyed: 171 had senile cataract, 162 had open-angle glaucoma, and 159 had healthy eyes. A modified food frequency questionnaire was administered to elicit ophthalmic nutrition knowledge and dietary intake information of participants over the last 30-days. The results were compared between the three groups.

RESULTS

More than half of the participants (n = 267; 54.3 per cent) had received some form of education on food sources that are good for the eyes and vision, with healthy participants accounting for 50.6 per cent of this proportion. Television (55.1 per cent; 147/267), radio (49.1 per cent; 131/267) and the eye doctor (34.1 per cent; 91/267) were the most frequent sources of ophthalmic nutritional knowledge. Overall, less than one-quarter of the participants (n = 108; 22.2 per cent) were able to correctly identify one food source for at least four out of seven selected ophthalmic nutrients. Vitamin C was the most frequently consumed ophthalmic nutrient, whereas lycopene was the least taken across all groups. The average ophthalmic nutrients intake score for those with healthy eyes (59.16 [53.39-64.93]) was significantly greater than for both glaucoma patients (37.73 [32.01-43.44]) and cataract patients (34.81 [29.24-40.37]).

CONCLUSION

In addition to poor ophthalmic nutrition awareness and knowledge, both cataract and glaucoma patients, compared to those with healthy eyes, consumed a lesser amount of nutrients considered vital for eye health and vision. Ophthalmic nutrition education is needed to improve eye-health outcomes.

Knowledge of Ghanaian Graduating Undergraduate Nurses About Ageing

Introduction

Knowledge on ageing has an impact on the quality of care provided to older people. Although older Ghanaians provide various forms of support to family and communities, many of them experience poor nursing care in the Ghanaian health system. There is, however, dearth of evidence regarding knowledge of ageing among Ghanaian nurses.

Objective

This study therefore used a descriptive survey approach to investigate knowledge of graduating undergraduate nurses on physiological, and psychosocial changes in ageing.

Methods

Seventy graduating undergraduate nurses were surveyed to identify their knowledge on physiological and psychosocial changes leading to care needs of older people in Ghana. Three undergraduate nursing programs with gerontological nursing courses were purposively selected for the study. Descriptive statistics were used to analyze the data in order to present quantitative descriptions of variables in this study.

Results

The response rate in the study was 42%. Findings of the study show graduating undergraduate nursing students have inadequate knowledge on ageing. Several gaps in knowledge regarding ageing were identified. Although undergraduate nursing schools had gerontological nursing courses in their programs, over 90% of participating graduating nursing students indicated pain, anxiety and depression are normal aspects in the ageing process.

Conclusion

It is imperative to improve the current curricula content on gerontological nursing in Ghanaian nursing schools to equip nurses with knowledge and skills needed to provide quality healthcare to older people in Ghana. Improving knowledge on ageing through evidence-informed gerontological nursing curricula content will lead to better nursing care of older Ghanaians. Providing educational opportunities for improved quality nursing care of older Ghanaians is in line with the United Nations (UN) Sustainable Development Goal 3, which aims at providing equal and quality healthcare to all age groups by 2030.

[Visual Impairment and Eye Diseases in St. Louis, Senegal]

Background

Few epidemiological data describe the prevalence of blindness and visual impairment in Senegal. Data from West African studies estimate blindness prevalence between 1.2 - 3.4% and that of visual impairment between 10.4 - 17.1%. IRIS Mundial (IM) is a non-governmental organization collaborating with l'Association St-Louisienne pour la Vue (ASV) to develop eye care in Senegal.

Objective

Describe the relative importance of and causes of blindness and visual impairment in a population consulting for vision problems in the Senegalese region of St. Louis, to assist in planning of relevant eye care programs.

Methods

Results from eye exams carried out by a team from IM in 2018 have been complied and analyzed.

Results

In all, 1944 patients were examined (56.5% female). Some 25.7% of patients presented a visual impairment (22.5% moderate; 3.2% severe). Regarding refractive error, 15.3% of patients had myopia, 10.7% had hyperopia, 54.8% had astigmatism and 55.8% were presbyopic. Clinically significant cataracts is present in 17.4% of patients and glaucoma in 2.5%.

Conclusion

Our data give a glimpse of the prevalence of visual impairment and ocular disease in St. Louis, Senegal. Uncorrected refractive error, cataracts and glaucoma are present in this population and may guide the planning of relevant eye care interventions.

Autophagy stimulation reduces ocular hypertension in a murine glaucoma model via autophagic degradation of mutant myocilin

Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) damage is associated with primary open-angle glaucoma (POAG). Myocilin mutations resulting in elevated IOP are the most common genetic causes of POAG. We have previously shown that mutant myocilin accumulates in the ER and induces chronic ER stress, leading to TM damage and IOP elevation. However, it is not understood how chronic ER stress leads to TM dysfunction and loss. Here, we report that mutant myocilin activated autophagy but was functionally impaired in cultured human TM cells and in a mouse model of myocilin-associated POAG (Tg-MYOCY437H). Genetic and pharmacological inhibition of autophagy worsened mutant myocilin accumulation and exacerbated IOP elevation in Tg-MYOCY437H mice. Remarkably, impaired autophagy was associated with chronic ER stress-induced transcriptional factor CHOP. Deletion of CHOP corrected impaired autophagy, enhanced recognition and degradation of mutant myocilin by autophagy, and reduced glaucoma in Tg-MYOCY437H mice. Stimulating autophagic flux via tat-beclin 1 peptide or torin 2 promoted autophagic degradation of mutant myocilin and reduced elevated IOP in Tg-MYOCY437H mice. Our study provides an alternate treatment strategy for myocilin-associated POAG by correcting impaired autophagy in the TM.

Comparison of vertical cup-to-disc ratio estimates using stereoscopic and monoscopic cameras

BACKGROUND

The use of monoscopic cameras for glaucoma screening is increasing due to their portability, lower cost, and non-mydriatic capabilities. However, it is important to compare the accuracy of such devices with stereoscopic cameras that are used clinically and are considered the gold standard in optic disc assessment. The aim of this study is to compare vertical cup-to-disc ratio (VCDR) estimates obtained using images taken with a monoscopic and stereoscopic camera.

METHODS

Participants were selected from the Tema Eye Survey. Eligible subjects had images of at least one eye taken with two cameras. They were classified as meeting the glaucoma threshold if an eye had a VCDR estimate >97.5th percentile, corresponding to >0.725 for this population. Hence, we used 0.725 as the cutoff to group eyes into two categories: positive and negative. We calculated sensitivity, specificity, and predictive values of VCDR assessed by expert readers at a reading center for monoscopic photos using stereoscopic photos as the gold standard.

RESULTS

Three hundred and seventy-nine eyes of 206 participants were included in the study. Most participants were female (60.2%) and the most common age group was 50-59 years (36.4%). Sixteen eyes met the glaucoma threshold (VCDR > 0.725). Of these, the VCDR estimates of 14 eyes (87.5%) disagreed on the glaucoma threshold from the two cameras. The sensitivity to detect glaucoma with the monoscopic camera was 14.3% (95% CI: 4.0, 40.3).

CONCLUSIONS

The low sensitivity of monoscopic photos suggests that stereoscopic photos are more useful in the diagnosis of glaucoma.

Prevalence and associated factors of vision loss in the South African National Health and Nutrition Examination Survey (SANHANES-1)

BACKGROUND

Vision loss is a major public health concern that significantly affects developing countries, including South Africa. Although existing literature have reported on the prevalence, causes, and impact of vision loss on the quality of life of affected individuals (children and adults) in parts of South Africa, there is no evidence of the prevalence and associated factors of vision loss in the general population. Hence, this study aimed to determine the prevalence of vision loss and its associated factors in South Africa using a population-based survey.

METHODS

Secondary analyses were conducted using data from the South African National Health and Nutrition Examination Survey (SANHANES-1), a population-based national health survey conducted from 2011 to 2012. Vision loss was defined as presenting visual acuity (PVA) worse than Snellen 6/12 in the better eye. Visual acuity was assessed by clinicians and participants' subjective response to vision-related questions. Univariate and multiple logistic regression models were used to examine the association of the independent variables with vision loss.

RESULTS

The analytic sample comprised 4346 individuals with a mean age of 39.1 years. Female sex accounted for 55.6% of the participants. The prevalence of vision loss among participants was 9.2% (95% CI: 7.7-10.9). Older age (45-54 years, OR = 2.99, p < 0.001; 55-64 years, OR = 5.78, p < 0.001 and ≥ 65 years, OR = 5.12, p < 0.001), female sex (OR = 1.50, p = 0.016), and previous diabetes diagnosis (OR = 2.28, p = 0.001) were significantly associated with increased odds of vision loss. Further, secondary school education (OR = 0.71, p = 0.031), white ethnicity (OR = 0.11, p = 0.007), residing in Mpumalanga province (OR = 0.12, p < 0.001) and having never had an eye examination (OR = 0.56, p = 0.003) were significantly associated with reduced odds of vision loss.

CONCLUSION

Almost one in ten participants had vision loss. Adopting strategies targeted at reducing barriers to the utilization of eye care services will promote early detection and management of blinding conditions, and thereby, decrease the burden of vision loss in South Africa.

Ophthalmic manifestations and vision impairment in Lassa fever survivors

The purpose of this study was to describe the ocular findings, structural ocular complications, and vision impairment in a cohort of Lassa fever survivors in Kenema, Sierra Leone. A retrospective, uncontrolled, cross-sectional study of 31 Lassa fever survivors (62 eyes) who underwent an ophthalmic evaluation in January 2018 at the Kenema Government Hospital in Kenema, Sierra Leone was performed. Data collection included demographic information, ocular/systemic symptoms, visual acuity (VA), and ophthalmic examination findings. Main outcome measures included anterior and posterior segment ophthalmic manifestations and level of VA impairment in Lassa fever survivors. Anterior segment findings included cataract (18%) and pterygium (2%), while posterior segment manifestations consisted of glaucoma (6%), preretinal hemorrhage (2%), and lattice degeneration (2%). Findings suggestive of prior sequelae of uveitis included chorioretinal scarring (5%), retinal fibrosis (3%), and vitreous opacity (2%). Visual acuity was normal/mildly impaired in 53 eyes (85%), moderately impaired in 6 eyes (10%), and 3 eyes (5%) were considered blind by the World Health Organization (WHO) criteria. Median VA was worse in Lassa fever survivors with ophthalmic disease findings (p<0.0001) for both anterior segment (p<0.0001) and posterior segment disease (p<0.013). Untreated cataract was a significant cause of visual acuity impairment (p<0.0001). Lassa fever survivors in this cohort were found to have cataract and posterior segment findings that potentially represent sequelae of uveitis associated with visual impairment. Future studies are warranted to improve our understanding of the spectrum of ocular disease in this emerging infectious disease of public health consequence.

ATF4 leads to glaucoma by promoting protein synthesis and ER client protein load

The underlying pathological mechanisms of glaucomatous trabecular meshwork (TM) damage and elevation of intraocular pressure (IOP) are poorly understood. Here, we report that the chronic endoplasmic reticulum (ER) stress-induced ATF4-CHOP-GADD34 pathway is activated in TM of human and mouse glaucoma. Expression of ATF4 in TM promotes aberrant protein synthesis and ER client protein load, leading to TM dysfunction and cell death. These events lead to IOP elevation and glaucomatous neurodegeneration. ATF4 interacts with CHOP and this interaction is essential for IOP elevation. Notably, genetic depletion or pharmacological inhibition of ATF4-CHOP-GADD34 pathway prevents TM cell death and rescues mouse models of glaucoma by reducing protein synthesis and ER client protein load in TM cells. Importantly, glaucomatous TM cells exhibit significantly increased protein synthesis along with induction of ATF4-CHOP-GADD34 pathway. These studies indicate a pathological role of ATF4-CHOP-GADD34 pathway in glaucoma and provide a possible treatment for glaucoma by targeting this pathway.

Visual impairment and social isolation, depression and life satisfaction among older adults in Ghana: analysis of the WHO's Study on global AGEing and adult health (SAGE) Wave 2

AIM

To estimate the prevalence of visual impairment (VI) and associated factors and further quantify its association with social isolation, depression and life satisfaction among older adults in Ghana.

METHODS

WHO Study on Global AGEing and Adult Health Ghana dataset for older adults 50 years and above was used for this study. Social isolation, depression and life satisfaction were our primary outcomes with VI being our secondary outcome. We employed negative binomial, Poisson and generalised negative binomial regression models individually modified with Coarsened Exact Matching method of analysis. All analysis was performed by adopting robust SE estimation using Stata V.15.

RESULTS

The prevalence of VI was 17.1% (95% CI14.3 to 20.2) and the factors associated include age groups, educational level, religion, region, where the participant was born, and difficulty in work/households activity (p<0.05). The inferential analysis shows that the significant log-likelihood score of social isolation and life satisfaction for older adults with VI was 0.25 more (95% CI 0.03 to 0.47) and 0.04 less (95% CI -0.08 to -0.01), respectively, compared with those without VI. The prevalence of depression among older adults with VI was significantly 90% higher compared with non-VI (adjusted prevalence ratio (95% CI) = 1.90 (1.17 to 3.09), p<0.001).

CONCLUSION

The prevalence of VI is associated with increasing age, educational level and self-rated health. VI was identified to be associated with social isolation, depression and diminishing life satisfaction. In order to achieve sustainable development goal #3, a national focus on geriatric care as part of the implementation of the National Ageing Policy will garner improvement in the quality of life of older adults with visual VI in Ghana. Eye health practitioners at all levels of the health systems should consider the psychosocial consequences of VI for the optimum care of the older adult client.

Update on the genetics of primary open-angle glaucoma

Affecting nearly 80 million individuals, glaucoma is the number one cause of irreversible blindness in the world. This ocular disease describes a set of optic neuropathies of which primary open angle glaucoma (POAG) is the most common. POAG is associated with progressive visual field deterioration resulting from damage to the optic nerve and loss of retinal ganglion cells. Risk factors for POAG include elevated intraocular pressure, aging, African and Hispanic ancestry, and a positive family history of POAG. Multiple genes have been found to contribute to POAG. Much of POAG genetics and pathology has yet to be explained. Recent genome-wide association studies have identified a large number of novel loci associated with POAG and its endophenotypes. Genomic and proteomic profiling of biofluids has contributed to our knowledge of differential gene expression in POAG. Functional studies both in cell culture and animal models have confirmed the effects of variants and differential gene expression on ocular physiology while in silico analyses have increased our understanding of disease risk and progression so that we might better diagnose and treat this complex genetic illness.

Prevalence, Causes, and Factors Associated with Visual Impairment and Blindness among Registered Pensioners in Ghana

Purpose

To determine the prevalence, causes, and factors associated with presenting visual impairment and blindness among pensioners.

Design

A nationwide cross-sectional study. This study was part of the analysis on data obtained in the pensioners' medical survey conducted among members of the National Pensioners Association in Ghana.

Method

(i) Setting: it was a multicenter study involving thirteen centers throughout Ghana with a center in each regional capital. (ii) Study population: the study involved 4813 pensioners. (iii) Observation procedures: data were captured through the use of questionnaires, physical examinations including eye examinations, and urine and blood sample analysis. (iv) Main outcome measure: presenting visual impairment and blindness (as defined by the WHO ICD-10 classification).

Results

The overall prevalence of blindness among pensioners in Ghana was 3.8% (95% CI = 3.2–4.4), while the prevalence of moderate and severe visual impairment was 21.7% (95% CI = 20.5–23.0). The prevalence of blindness was lowest in the 60–65-year-old age group (2.1% (95% CI = 1.3–2.8)) and highest in the above 80-year-old age group (12.2% (95% CI = 6.6–17.8)). Cataract was the leading cause of blindness (62.4%) and moderate and severe visual impairment (55.7%). Factors significantly associated with blindness and visual impairment include educational status, vegetarianism, arthritis, and having proteins in urine.

Conclusion

There is a high prevalence of visual impairment and blindness among the pensioners in Ghana. Sadly, the greatest cause was cataract, which is correctable. Increase in formal education status will be important in the prevention of blindness and visual impairment.

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.

Barriers and incentives for conducting research amongst the ophthalmologists in Sub-Sahara Africa

Background

Research is a critical component amongst the strategies to improve health outcomes of any country. The role of research assumes greater importance in Africa as it carries a larger share of the global burden of diseases, blindness, and low vision. “Vision 2020- the Right to Sight” is a WHO-IAPB collaborated initiative aiming to eliminate preventable blindness by the year 2020. High quality research in eye care is imperative for the initiative to succeed, however, there is a dearth of research in eye care in sub-Saharan Africa in general and specifically in the Eastern, Central, and Southern African (ECSA) region. Identifying the barriers that hamper research in this region is an important step towards the elimination of preventable blindness.

Methods

A structured questionnaire using the SurveyMonkey program was sent to ophthalmologists in the ECSA region and South Africa through their respective regional professional bodies.

Results

Lack of funding, inadequate time and poor research knowledge were the main research barriers while the ability to improve eye health care through research was the main incentive for conducting research. The response rate for South Africa was low, restricting comparisons with other ECSA countries.

Conclusion

The barriers mainly center on financial, human and administrative infrastructure and resources. In spite of the barriers, ophthalmologists in the study region are enthusiastic in research aiming to increase evidence—based knowledge to improve eye health care in line with the goals of “Vision 2020- the Right to Sight” initiative.

Eight-Year Incidence of Open-Angle Glaucoma in the Tema Eye Survey

PURPOSE

To determine the incidence of open-angle glaucoma (OAG) and its risk factors in the Tema Eye Survey in Ghana, West Africa.

DESIGN

Longitudinal, observational population-based study.

PARTICIPANTS

One thousand two hundred five of 1500 participants 40 years of age or older selected randomly from 5603 participants originally drawn from the population and who had undergone a baseline examination.

METHODS

All participants underwent baseline and follow-up ophthalmologic examinations 8 years apart. Glaucoma diagnosis was determined based on the International Society for Geographical and Epidemiologic Ophthalmology criteria.

MAIN OUTCOME MEASURES

Incidence and odds ratio (OR).

RESULTS

The response rate was 80.3%. Of 1101 nonglaucomatous participants at baseline who had complete follow-up data, 4.6% (95% confidence interval [CI], 3.7%-5.2%) demonstrated OAG over the 8-year period, or 0.58% (95% CI, 0.4%-0.8%) per year. The 8-year incidence increased with age from 3.1% in those 40 to 49 years old to 7.0% in those 60 to 69 years old. Baseline risk factors for incident OAG were male gender (OR, 2.1; 95% CI, 1.1-4.0; P = 0.025), older age relative to those 40 to 49 years old (those 50-50 years old: OR, 2.6; 95% CI, 1.2-5.7; those 60-69 years old: OR, 4.3; 95% CI, 2.0-8.8; and for those 70 years of age and older: OR, 6.3; 95% CI, 2.6-15.4; all P < 0.001), higher intraocular pressure (IOP; OR, 1.4; 95% CI, 1.1-1.8; P < 0.001), larger vertical cup-to-disc ratio (OR, 5.8; 95% CI, 5.2-6.6; P < 0.001), and thinner central cornea (OR, 1.2; 95% CI, 1.03-1.5; P = 0.013). A separate analysis performed with central corneal thickness-based IOP correction did not change the outcome of the associative model of incident glaucoma.

CONCLUSIONS

The incidence of OAG is higher in this population than reported in nonblack populations outside Africa. This is important not only in Ghana and probably other West African countries but also wherever people of the West African diaspora reside. These data enhance our understanding of the epidemiologic factors of OAG in this setting and may serve as reference for public health policy and planning.

Longitudinal Change in Central Corneal Thickness in the Tema Eye Survey

PURPOSE

To determine the change and rate of change in central corneal thickness (CCT) and their determinants.

DESIGN

Longitudinal observational population-based study.

METHODS

A total of 758 normal and 58 glaucomatous subjects underwent complete eye examination, with CCT measurements at 2 separate visits. Change and rate of change in CCT were determined. Univariate and multivariate linear regression analyses were performed to determine the factors associated with change and rate of change.

RESULTS

The mean follow-up duration was 8.4 ± 0.7 years. The overall change was -8.9 ± 16.7 μm in OD and -9.8 ± 16.2 μm in OS, both P < .0001. Changes in glaucomatous and normal subjects were -14.1 ± 2.2 μm vs -8.6 ± 0.6 μm in OD (P = .02) and -14.5 ± 2.2 μm vs -9.5 ± 0.6 μm in OS (P = .03), respectively. The overall rate of thinning was -1.1 μm/year (OD) and -1.2 μm/year (OS). Rates in glaucomatous and normal eyes were -1.7 ± 0.3 μm/year vs -1.0 ± 0.1 μm/year in OD (P = .02) and -1.7 ± 0.3 μm/year vs -1.1 ± 0.1 μm/year in OS (P = .03), respectively. Change and rate of change were associated with baseline CCT (ß = -0.1 to -0.09 and -0.011, respectively, all P < .001) and glaucoma (ß = -6.8 to -5.6, P ≤ .009, and -0.75 to -0.69, P ≤ .007, respectively).

CONCLUSION

CCT decreased significantly over time. The change and rate of change were greater in glaucomatous than normal eyes, and were greater than described in cross-sectional studies.

Performance of an iPad Application to Detect Moderate and Advanced Visual Field Loss in Nepal

PURPOSE

To evaluate the accuracy and efficiency of Visual Fields Easy (VFE), a free iPad app, for performing suprathreshold perimetric screening.

DESIGN

Prospective, cross-sectional validation study.

METHODS

We performed screening visual fields using a calibrated iPad 2 with the VFE application on 206 subjects (411 eyes): 210 normal (NL), 183 glaucoma (GL), and 18 diabetic retinopathy (DR) at Tilganga Institute of Ophthalmology, Kathmandu, Nepal. We correlated the results with a Humphrey Field Analyzer using 24-2 SITA Standard tests on 373 of these eyes (198 NL, 160 GL, 15 DR).

RESULTS

The number of missed locations on the VFE correlated with mean deviation (MD, r = 0.79), pattern standard deviation (PSD, r = 0.60), and number of locations that were worse than the 95% confidence limits for total deviation (r = 0.51) and pattern deviation (r = 0.68) using SITA Standard. iPad suprathreshold perimetry was able to detect most visual field deficits with moderate (MD of -6 to -12 dB) and advanced (MD worse than -12 dB) loss, but had greater difficulty in detecting early (MD better than -6 dB) loss, primarily owing to an elevated false-positive response rate. The average time to perform the Visual Fields Easy test was 3 minutes, 18 seconds (standard deviation = 16.88 seconds).

DISCUSSION

The Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss. Improvements are currently underway to monitor eye and head tracking during testing, reduce testing time, improve performance, and eliminate the need to touch the video screen surface.

Visual impairment and blindness in a population-based study of Mashhad, Iran

Purpose

To determine the prevalence of visual impairment and blindness and related factors in the 1- to 90-year-old urban population of Mashhad.

Methods

In this cross-sectional study of 1- to 90-year-old residents of Mashhad, in northeastern Iran, sampling was done through random stratified cluster sampling (120 clusters). After selecting the samples and their participation in the study, all subjects had vision testing including measurement of visual acuity and refraction, as well as examinations with the slit-lamp and ophthalmoscopy. Visual impairment (primary outcomes) was defined as a visual acuity worse than of 0.5 logMAR (20/60) in the better eye.

Results

Of the 4453 selected persons, 3132 (70.4%) participated in the study. The prevalence of visual impairment based on presenting vision and best-corrected vision was 3.95% (95% confidence interval [CI]: 3.13–4.77) and 2.23 (95% CI: 1.54–2.91), respectively. The prevalence of presenting visual impairment increased from 1.59% in children under 5 years of age to 43.59% in people older than 65 years of age; these figures were respectively 1.59% and 42.31% based on corrected visual acuity. In the logistic regression model, older age (OR = 1.06, 95% CI: 1.04–1.07, P < 0.001), higher education (OR = 0.16, 95% CI: 0.06–0.38, P < 0.001), and low income (OR = 1.36, 95% CI: 1.21–1.72, P < 0.001) correlated with impaired sight. Based on presenting vision and best-corrected vision, the prevalence of blindness was 0.86% (95% CI: 0.51–1.22) and 0.32% (95% CI: 0.1–0.55). The most common causes of visual impairment were uncorrected refractive error (41.8%) and cataract (20%).

Conclusions

According to our findings, the prevalence of visual impairment was intermediate in comparison with other studies. The prevalence of visual impairment in our study was similar to the global average; however, it was markedly high at older ages. Nonetheless, refractive errors and cataracts remain as the main causes of impaired vision and blindness in this population, while these two conditions are easily treatable with correction or surgery.

Major review: Molecular genetics of primary open-angle glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG), the most common type, is a complex inherited disorder that is characterized by progressive retinal ganglion cell death, optic nerve head excavation, and visual field loss. The discovery of a large, and growing, number of genetic and chromosomal loci has been shown to contribute to POAG risk, which carry implications for disease pathogenesis. Differential gene expression analyses in glaucoma-affected tissues as well as animal models of POAG are enhancing our mechanistic understanding in this common, blinding disorder. In this review we summarize recent developments in POAG genetics and molecular genetics research.

A comparison of cup-to-disc ratio estimates by fundus biomicroscopy and stereoscopic optic disc photography in the Tema Eye Survey

PurposeTo determine if there are systematic differences in cup-to-disc ratio (CDR) grading using fundus biomicroscopy compared to stereoscopic disc photograph reading.MethodsThe vertical cup-to-disc ratio (VCDR) and horizontal cup-to-disc ratio (HCDR) of 2200 eyes (testing set) were graded by glaucoma subspecialists through fundus biomicroscopy and by a reading center using stereoscopic disc photos. For validation, the glaucoma experts also estimated VCDR and HCDR using stereoscopic disc photos in a subset of 505 eyes that they had assessed biomicroscopically. Agreement between grading methods was assessed with Bland-Altman plots.ResultsIn both sets, photo reading tended to yield small CDRs marginally larger, but read large CDRs marginally smaller than fundus biomicroscopy. The mean differences in VCDR and HCDR were 0.006±0.18 and 0.05±0.18 (testing set), and -0.053±0.23 and -0.028±0.21 (validation set), respectively. The limits of agreement were ~0.4, which is twice as large as the cutoff of clinically significant CDR difference between methods. CDR estimates differed by 0.2 or more in 33.8-48.7% between methods.ConclusionsThe differences in CDR estimates between fundus biomicroscopy and stereoscopic optic disc photo reading showed a wide variation, and reached clinically significance threshold in a large proportion of patients, suggesting a poor agreement. Thus, glaucoma should be monitored by comparing baseline and subsequent CDR estimates using the same method rather than comparing photographs to fundus biomicroscopy.

Epidemiology of dry eye disease in Africa: The sparse information, gaps and opportunities

Dry eye disease (DED) is an increasingly significant clinical problem in developing countries and/or emerging economies. Existing studies on DED conducted in these areas have largely reported on associations between DED and infectious disease (trachoma) and malnutrition (hypovitaminosis A), but current trends of industrialization, urbanization, and modernization in these areas could result in a shift to other forms of DED. Herein, we review the epidemiology of DED in these geographic areas, highlighting potential causes and risk factors of DED while presenting information on diagnostic tools and algorithms and insight into some treatment modalities of DED that could prove useful to clinicians and investigators in these regions.

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.

Glaucoma awareness, knowledge, perception of risk and eye screening behaviour among residents of Abokobi, Ghana

BACKGROUND

Although glaucoma is the lead cause of irreversible blindness globally, the condition shows no signs or symptoms until later stages. Knowledge about the disease is known to influence utilization of eye screening services. This study aimed at understanding knowledge and perception of risk for glaucoma, as well as eye screening behaviour among residents of Abokobi, a peri-urban community.

METHODS

This was a cross-sectional study that employed quantitative data collection methods, with the use of a questionnaire. Descriptive statistics were used to describe the socio-demographic characteristics, knowledge about glaucoma and eye screening behaviour. Also, associations between socio-demographic factors and awareness as well as perception of risk were analysed using Chi-square test or Univariate Fisher's exact test.

RESULTS

Out of a total of 300 respondents, 60.3 % were females and 39.3 % were aware of glaucoma. Majority (99.1 %) of respondents aware of glaucoma also agreed the disease can result in blindness with only (28 %) affirming that blindness from glaucoma is irreversible. Nearly half (49.7 %) of the respondents perceived themselves to be at risk of developing glaucoma. The results showed that age and education (p <0.0001) were statistically significant with glaucoma awareness. Approximately, 20.7 % of the respondents have had their eye screened with just a few (4.3 %) screening for glaucoma.

CONCLUSION

Although glaucoma awareness was high, the findings display inadequate knowledge about glaucoma. There is a need to effectively inform and educate people about the disease.

[Incidence and causes of visual impairment in the district of Mahdia, in east Tunisia: Retrospective study of 1487 cases]

OBJECTIVE

To study socio-demographic characteristics and main causes related to visual impairment (VI) as a function of age bracket and to analyze their trends over time in the district of Mahdia.

METHOD

A retrospective review was performed on 1487 cases of visual impairment registered with the social authorities in Mahdia, between 1980 and 2013. The social, demographic, vision exam findings and causes were ascertained and analyzed in an SPSS database. Incidence rates of VI and blindness due to various causes were calculated based on the demographic data from the NSI to estimate the time trends using the general linear regression model and Spearman correlation.

RESULTS

Analyses included 1487 participants with a median age of 47 years, 40.6% of cases were aged under 45 years. Children accounted for 11.1% (165 patients), while age was between 16 and 45 years in 29.5% (439 patients), between 46 and 65 years in 31.5% (469 patients) and greater than 65 years in 27.8% (414 patients). The sex-ratio (M/F) was 1.78. Socially, 51% came from rural areas, 62% were illiterate, and 84% were unemployed. We observed blindness in 70% of participants and low vision in 30%. In children, the causes were dominated by congenital cataract and congenital glaucoma, each present in 31 children (18.8%). Between 16 and 45 years, glaucoma and hereditary dystrophies of the retina were found in 62 and 61 patients respectively (14% each). For age between 46 and 65 years, trachoma was responsible for 19.8% of cases of VI, glaucoma in 15.8% and cataract in 15.1%. Beyond 65 years, glaucoma accounted for 30.7% of the causes of VI and cataract 27.8% of cases. Trend analysis shows a significant increase in the incidence rate of visual impairment with an average of 12% per year (P=0.001). The mean age increased by 46% (P=0.003). Trachoma increased by 118% (P<0.0001) between 1980 and 1990, then declined by 42% (P=0.0013) between 1991 and 2013. Incidence of VI significantly increased by 4% for cataract (P=0.001), 23% (P=0.001) for glaucoma and 20% (P=0.02) for diabetic retinopathy, while VI related to refractive errors and AMD showed no significant change.

CONCLUSION

Advanced age, lower educational and socio-economic status were associated with bilateral VI. Age related eye problems are the main causes of VI, and their incidence is tending to increase. Public health policies and procedures should be targeted to risk related populations and age-related diseases in order to control the incidence of visual impairment and avoid its consequences.

Central Corneal Thickness and its Associations With Ocular and Systemic Factors in an Urban West African Population

PURPOSE

To assess the associations of central corneal thickness (CCT) with ocular and systemic factors in a West African population.

DESIGN

Population-based cross-sectional study.

METHODS

Participants aged ≥40 years in the Tema Eye Survey who had clinically normal corneas were included in this study. CCT was determined bilaterally using handheld ultrasound pachymetry. The association between CCT and ocular or systemic factors was analyzed with univariable linear regression. Multivariable linear regression analysis was performed for variables significantly associated with CCT in the univariable analysis. Main outcome measures were CCT (μm) and its associations with age, sex, IOP, cup-to-disc ratio (CDR), glaucoma, hypertension, and diabetes.

RESULTS

A total of 6806 eligible subjects were identified, of whom 5603 (82.3%) participated in the Tema Eye Survey. A total of 4737 participants (84.5% of participants) of West African descent and clinically normal corneas were included. The mean age ± standard deviation (SD) of participants was 51.2 ± 9.7 years and 38.7% were male. The mean ± SD CCT in the population was 533.9 ± 34.0 μm. In the multivariable linear regression analysis, increased CCT was significantly associated with younger age, male sex, and higher IOP (all P < .001). There were no significant associations between CCT and CDR, glaucoma, hypertension, and diabetes.

CONCLUSIONS

This population-based cross-sectional survey of West African adults found a significant association between increased CCT and younger age, male sex, and higher IOP but not glaucoma or CDR. Variations in corneal thickness may influence the accuracy of IOP measurements in African persons.

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.

Ocular Health and Safety Assessment among Mechanics of the Cape Coast Metropolis, Ghana

Purpose:

To conduct an ocular health and safety assessment among mechanics in the Cape Coast Metropolis, Ghana.

Methods:

This descriptive cross sectional study included 500 mechanics using multistage sampling. All participants filled a structured questionnaire on demographic data, occupational history and ocular health history. Study participants underwent determination of visual acuity (VA) using LogMAR chart, external eye examination with a handheld slit lamp biomicroscope, dilated fundus examination, applanation tonometry and refraction.

Results:

Out of 500 mechanics, 433 were examined (response rate, 87%) comprised of 408 (94.2%) male and 25 (5.8%) female subjects. The prevalence of visual impairment (i.e. presenting VA < 6/18) among the respondents was 2.1%. Eye injuries were reported in 171 (39.5%) mechanics probably due to the large number of workers, 314 (72.5%), who did not use eye protective devices. Mechanics in the auto welding category were at the highest risk of sustaining an eye injury (odds ratio [OR], 13.4; P < 0.001). Anterior segment ocular disorders were mostly pterygia while posterior segment eye disorders included glaucoma suspects and retinochoroidal lesions. The development of pterygia was associated with the number of years a mechanic stayed on the job. Eye care seeking behavior among the participants was poor.

Conclusion:

Eye injuries were prevalent among the mechanics as the use of eye protection was low. Eye safety should be made an integral part of the public health agenda in the Cape Coast Metropolis.

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.

Prevalence and Causes of Visual Impairment and Blindness in Central Iran; The Yazd Eye Study

PURPOSE

To determine the prevalence and causes of blindness and visual impairment (VI) in Yazd, central Iran.

METHODS

This population-based, cross-sectional study was performed on adults aged 40-80 years, residing in Yazd district, in 2010-2011. Eligible subjects were selected using cluster random sampling. Each participant underwent an interview and complete ophthalmologic examination. Blindness and VI were defined as best-corrected visual acuity (VA) <3/60 and < 6/18 in the better eye, respectively.

RESULTS

Out of 2,320 eligible individuals, 2,098 participated in the study (90.4% response rate), of whom, 2,023 subjects completed all evaluations. The standardized prevalence of blindness and VI were 0.7% (95% confidence interval [CI], 0.3-1.0%) and 4.4% (95% CI, 3.3-5.4%), respectively which was significantly associated with older age (odd ratio [OR] = 3.2, 95% CI: 1.9-5.2 and OR = 3.1, 95% CI: 2.3-4.2, respectively) and female sex (OR = 3.6, 95% CI: 1.1-12.3 and OR = 1.7, 95% CI: 1.2-2.5, respectively). The proportion of avoidable causes of blindness and VI were 92.9% (95% CI: 80.0-100.0%) and 76.6% (95% CI: 69.2-85.0%), respectively. Major causes of blindness were diabetic retinopathy (50.0%), glaucoma (21.4%) and cataracts (14.3%) whereas main causes of VI were cataracts (41.5%), diabetic retinopathy (17.0%) and age-related macular degeneration (13.8%).

CONCLUSIONS

Diabetic retinopathy, glaucoma, cataract and age-related macular degeneration were the leading causes of blindness and VI in Yazd, most of which are avoidable. Planning for prevention of blindness is highly recommended to decrease the proportion of avoidable blindness.

Solar ultraviolet radiation in Africa: a systematic review and critical evaluation of the health risks and use of photoprotection

The majority of the African continent experiences high solar UVB radiation throughout the year. The adverse consequences of this on the health of populations living in Africa are reviewed.

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.

Pigmentary disorders of the eyes and skin

Oculocutaneous albinism, Menkes syndrome, tuberous sclerosis, neurofibromatosis type 1, dyskeratosis congenita, lentiginosis profusa syndrome, incontinentia pigmenti, and Waardenburg syndrome all are genodermatoses that have well established gene mutations affecting multiple biological pathways, including melanin synthesis, copper transport, cellular proliferation, telomerase function, apoptosis, and melanocyte biology. Onchocerciasis results from a systemic inflammatory response to a nematode infection. Hypomelanosis of Ito is caused by chromosomal mosaicism, which underlies its phenotypic heterogeneity. Incomplete migration of melanocytes to the epidermis and other organs is the underlying feature of nevus of Ota. Vogt-Koyangi-Harada and vitiligo have an autoimmune etiology; the former is associated with considerable multiorgan involvement, while the latter is predominantly skin-limited.

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.

Discovery and functional annotation of SIX6 variants in primary open-angle glaucoma

Glaucoma is a leading cause of blindness worldwide. Primary open-angle glaucoma (POAG) is the most common subtype and is a complex trait with multigenic inheritance. Genome-wide association studies have previously identified a significant association between POAG and the SIX6 locus (rs10483727, odds ratio (OR) = 1.32, p = 3.87×10⁻¹¹). SIX6 plays a role in ocular development and has been associated with the morphology of the optic nerve. We sequenced the SIX6 coding and regulatory regions in 262 POAG cases and 256 controls and identified six nonsynonymous coding variants, including five rare and one common variant, Asn141His (rs33912345), which was associated significantly with POAG (OR = 1.27, p = 4.2×10⁻¹⁰) in the NEIGHBOR/GLAUGEN datasets. These variants were tested in an in vivo Danio rerio (zebrafish) complementation assay to evaluate ocular metrics such as eye size and optic nerve structure. Five variants, found primarily in POAG cases, were hypomorphic or null, while the sixth variant, found only in controls, was benign. One variant in the SIX6 enhancer increased expression of SIX6 and disrupted its regulation. Finally, to our knowledge for the first time, we have identified a clinical feature in POAG patients that appears to be dependent upon SIX6 genotype: patients who are homozygous for the SIX6 risk allele (His141) have a statistically thinner retinal nerve fiber layer than patients homozygous for the SIX6 non-risk allele (Asn141). Our results, in combination with previous SIX6 work, lead us to hypothesize that SIX6 risk variants disrupt the development of the neural retina, leading to a reduced number of retinal ganglion cells, thereby increasing the risk of glaucoma-associated vision loss.

Primary open angle glaucoma is a blinding disease for which there is currently no cure, only treatments that may slow its progress. To help understand the mechanisms of this disease and to design more effective treatments, we identified previously a locus, SIX6, that increases the risk of glaucoma. This gene is involved in early eye development and helps to form the retina. In this paper, we test specific sequence variants in SIX6 that are found in glaucoma patients. We show that these variants have a reduced function that interferes with their ability to direct proper formation of the retina. One variant in particular is common, and may be the main reason that this gene is important in the glaucoma disease process. Patients who have two copies of this sequence variant show a change in the structure of their eye consistent with fewer neurons that carry the visual signal to the brain. These neurons typically die as people age, and people who begin life with fewer visual neurons may have an increased risk of glaucoma. Additional research in this topic may lead to new treatments that preserve sight.

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.

Prevalence and causes of vision loss in sub-Saharan Africa: 1990-2010

AIM

To estimate the magnitude, temporal trends and subregional variation in the prevalence of blindness, and moderate/severe vision impairment (MSVI) in sub-Saharan Africa.

METHODS

A systematic review was conducted of published and unpublished population-based surveys as part of the Global Burden of Disease, Risk Factors and Injuries Study 2010. The prevalence of blindness and vision impairment by country and subregion was estimated.

RESULTS

In sub-Saharan Africa, 52 studies satisfied the inclusion criteria. The estimated age-standardised prevalence of blindness decreased by 32% from 1.9% (95% CI 1.5% to 2.2%) in 1990 to 1.3% (95% CI 1.1% to 1.5%) in 2010 and MSVI by 25% from 5.3% (95% CI 0.2% to 0.3%) to 4.0% (95% CI 0.2% to 0.3%) over that time. However, there was a 16% increase in the absolute numbers with blindness and a 28% increase in those with MSVI. The major causes of blindness in 2010 were; cataract 35%, other/unidentified causes 33.1%, refractive error 13.2%, macular degeneration 6.3%, trachoma 5.2%, glaucoma 4.4% and diabetic retinopathy 2.8%. In 2010, age-standardised prevalence of MSVI in Africa was 3.8% (95% CI 3.1% to 4.7%) for men and 4.2% (95% CI 3.6% to 5.3%) for women with subregional variations from 4.1% (95% CI 3.3% to 5.4%) in West Africa to 2.0% (95% CI 1.5% to 3.3%) in southern Africa for men; and 4.7% (95% CI 3.9% to 6.0%) in West Africa to 2.3% (95% CI 1.7% to 3.8%) in southern Africa for women.

CONCLUSIONS

The age-standardised prevalence of blindness and MSVI decreased substantially from 1990 to 2010, although there was a moderate increase in the absolute numbers with blindness or MSVI. Significant subregional and gender disparities exist.

Glaucoma drainage implant surgery--an evidence-based update with relevance to sub-Saharan Africa

Glaucoma represents a leading cause of preventable vision loss in Sub-Saharan Africa. Recent studies evaluating outcomes of glaucoma drainage implant (GDI) surgery suggest an important role for this approach in the African patient population. The Tube Versus Trabeculectomy study demonstrated a higher success rate with non-valved GDI surgery compared to trabeculectomy with mitomycin C after five years. The Ahmed Baerveldt Comparison study showed no difference in surgical failure rates between the Ahmed Glaucoma Valve and the Baerveldt Glaucoma Implant (BGI) but better intraocular pressure outcomes with the BGI at one year. The Ahmed Versus Baerveldt study demonstrated a lower failure rate for the BGI, but also a requirement for more post-operative interventions. Further study of GDI surgery in the Sub-Saharan Africa is necessary to determine its optimal place in the treatment paradigm for glaucoma patients in the region.

Relationship between glaucoma and admixture in postmenopausal African American women

OBJECTIVE

To investigate the association between African admixture and glaucoma prevalence among African American women.

DESIGN, SETTING, PARTICIPANTS

Participants included 11616 African American women from the Women's Health Initiative Study (WHI) for whom admixture information was available and included 2548 who self-reported a diagnosis of glaucoma.

MAIN OUTCOME MEASURES

Glaucoma.

RESULTS

Significant association was observed between self-identified glaucoma status and admixture. However, this association was not significant in a model that included neighborhood socioeconomic status (NSES), hypertension, diabetes and body mass index (BMI). Self-identified glaucoma status was associated with diabetes that persisted after adjustment for admixture, NSES, hypertension, and BMI. Lower NSES was also associated with higher glaucoma risk but this association was marginal in the fully adjusted model and neither hypertension nor BMI showed association. When glaucoma status was limited to those reporting use or no use of appropriate ophthalmologic medication, no associations were observed in any of the models.

CONCLUSION

This study failed to find an independent association of glaucoma status and African admixture and these findings suggest that the higher frequency glaucoma in African Americans may be largely due to other factors.

Investigation of known genetic risk factors for primary open angle glaucoma in two populations of African ancestry

PURPOSE

Multiple genes have been associated with primary open angle glaucoma (POAG) in Caucasian populations. We now examine the association of these loci in populations of African ancestry, populations at particularly high risk for POAG.

METHODS

We genotyped DNA samples from two populations: African American (1150 cases and 999 controls) and those from Ghana, West Africa (483 cases and 593 controls). Our analysis included 57 single nucleotide polymorphisms (SNPs) in five loci previously associated with POAG at the genome-wide level, including CDKN2B-AS1, TMCO1, CAV1/CAV2, chromosome 8q22 intergenic region, and SIX1/SIX6. We evaluated association in the full datasets, as well as subgroups with normal pressure glaucoma (NPG, maximum IOP ≤21 mm Hg) and high pressure glaucoma (HPG, IOP >21 mm Hg).

RESULTS

In African Americans, we identified an association of rs10120688 in the CDNK2B-AS1 region with POAG (P = 0.0020). Several other SNPs were nominally associated, but did not survive correction for multiple testing. In the subgroup analyses, significant associations were identified for rs10965245 (P = 0.0005) in the CDKN2B-AS1 region with HPG and rs11849906 in the SIX1/SIX6 region with NPG (P = 0.006). No significant association was identified with any loci in the Ghanaian samples.

CONCLUSIONS

POAG genetic susceptibility alleles associated in Caucasians appear to play a greatly reduced role in populations of African ancestry. Thus, the major genetic components of POAG of African origin remain to be identified. This finding underscores the critical need to pursue large-scale genome-wide association studies in this understudied, yet disproportionately affected population.