Blindness and visual impairment due to age-related cataract in sub-Saharan Africa: a systematic review of recent population-based studies

Bastawrous, Andrew; Dean, William H.; Sherwin, Justin C

doi:10.1136/bjophthalmol-2013-303135

Cited by 23 publications

(22 citation statements)

References 35 publications

(31 reference statements)

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“…In these countries, cataracts have been reported as the leading cause blindness. 23 This shows that the prevalence of blindness in this study is higher than in developed countries, and as expected, the prevalence of blindness is much higher in low income developing countries compared to developed countries.…”

Section: Discussionsupporting

confidence: 80%

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

Hashemi

Khabazkhoob

Saatchi

et al. 2018

Journal of Current Ophthalmology

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PurposeTo determine the prevalence of visual impairment and blindness and related factors in the 1- to 90-year-old urban population of Mashhad.MethodsIn 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.ResultsOf 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%).ConclusionsAccording 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.

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Section: Discussionsupporting

confidence: 80%

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

Hashemi

Khabazkhoob

Saatchi

et al. 2018

Journal of Current Ophthalmology

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“…17,[19][20][21][22][23] Quality of cataract surgery also remains a concern, with poor outcomes reaching 40% in some places. 24 In fact, many ophthalmologists do not perform surgery or may be inadequately trained. 17,25,26 Cataract, therefore, continues to be a challenge to tackle with the need to plan a comprehensive strategy addressing issues related to availability, affordability, accessibility, and acceptability of eye-care services, and improving outcome of cataract surgery in low-and middle-income countries.…”

Section: à50mentioning

confidence: 99%

Number of People Blind or Visually Impaired by Cataract Worldwide and in World Regions, 1990 to 2010

Khairallah

Kahloun

Bourne

et al. 2015

Invest. Ophthalmol. Vis. Sci.

311

205

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PURPOSE.To estimate prevalence and number of people visually impaired or blind due to cataract. METHODS.Based on the Global Burden of Diseases Study 2010 and ongoing literature research, we examined how many people were affected by moderate to severe vision impairment (MSVI; presenting visual acuity <6/18, ‡3/60) and blindness (presenting visual acuity <3/60) due to cataract. RESULTS.In 2010, of overall 32.4 million blind and 191 million vision impaired, 10.8 million people were blind and 35.1 million were visually impaired due to cataract. Cataract caused worldwide 33.4% of all blindness in 2010, and 18.4% of all MSVI. These figures were lower in the high-income regions (<15%) and higher (>40%) in South and Southeast Asia and Oceania. From 1990 to 2010, the number of blind or visually impaired due to cataract decreased by 11.4% and by 20.2%, respectively; the age-standardized global prevalence of cataract-related blindness and MSVI reduced by 46% and 50%, respectively, and the worldwide crude prevalence of cataract-related blindness and MSVI reduced by 32% and 39%, respectively. The percentage of global blindness and MSVI caused by cataract decreased from 38.6% to 33.4%, and from 25.6% to 18.4%, respectively. This decrease took place in almost all world regions, except East Sub-Saharan Africa.CONCLUSIONS. In 2010, one in three blind people was blind due to cataract, and one of six visually impaired people was visually impaired due to cataract. Despite major improvements in terms of reduction of prevalence, cataract remains a major public health problem.Keywords: cataract, epidemiology, blindness, visual impairment A lthough cataract is relatively easily, safely, and costefficiently treatable, and in spite of the increasing rates of cataract surgery, 1 cataract is still the leading cause of blindness and visual impairment worldwide, especially in developing countries. 2,3 Population-based studies and previous meta-analyses performed in different regions worldwide have reported that cataract is responsible for 47.8% to 51% of all global blindness. 2,4-9 However, these studies did not report data on the change during the past 2 decades in terms of prevalence and number of people blind or visually impaired due to cataract.The purpose of the current study was to determine, in a meta-analysis of all available population-based studies performed worldwide within the past 2 decades, prevalence and number of people affected by blindness and visual impairment due to cataract, to assess changes during the period from 1990 to 2010, and to examine regional differences in the prevalence of cataract-related blindness and visual impairment.

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“…The degradation of visual acuity in our patients is mainly due to the persistence of advanced O.volvulus –induced posterior eye segment lesions and secondary anomalies, mostly the evolution of cataract - the main cause for visual impairment worldwide [28] and in sub-Saharan Africa total blindness due to cataract ranges between 21% and 67% [29]. In urban Togo, the main ocular blinding disease was also found to be cataract with 8.3% prevalence [30], while in our patients, resident in rural central and northern Togo, the prevalence and incidence of cataract was higher and rising with age.…”

Section: Discussionmentioning

confidence: 99%

Sustainable Control of Onchocerciasis: Ocular Pathology in Onchocerciasis Patients Treated Annually with Ivermectin for 23 Years: A Cohort Study

Banla

Solim

Karabou³

et al. 2014

PLoS ONE

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The evolution and persistence of ocular pathology was assessed in a cohort of Onchocerca volvulus infected patients treated annually with ivermectin for 23 years. Patients were resident in rural Central and Kara Region of Togo and ocular examinations included testing of visual acuity, slit lamp examination of the anterior eye segment and the eye fundus by ophthalmoscopy. Before ivermectin treatment, vivid O.volvulus microfilariae (MF) were observed in the right and left anterior eye chamber in 52% and 42% of patients (n = 82), and dead MF were seen in the right and left cornea in 24% and 15% of cases, respectively. At 23 years post initial treatment (PIT), none of the patients (n = 82) presented with MF in the anterior chamber and cornea. A complete resolution of punctate keratitis (PK) lesions without observable corneal scars was present at 23 years PIT (p<0.0001), and sclerosing keratitits (SK) lessened by half, but mainly in patients with lesions at early stage of evolution. Early-stage iridocyclitis diminished from 42%(rE) and 40%(lE) to 13% (rE+lE)(p<0.0001), but advanced iridocyclitis augmented (p<0.001) at 23 years PIT compared to before ivermectin. Advanced-stage papillitis and chorioretinitis did not regress, while early-stage papillitis present in 28%(rE) and 27%(lE) of patients at before ivermectin regressed to 17%(rE) and 18%(lE), and early-stage chorioretinitis present in 51%(rE+lE) of cases at before ivermectin was observed in 12%(rE) and 13%(lE) at 23 years PIT (p<0.0001). Thus, regular annual ivermectin treatment eliminated and prevented the migration of O. volvulus microfilariae into the anterior eye chamber and cornea; keratitis punctata lesions resolved completely and early-stage sclerosing keratitits and iridocyclitis regressed, whilst advanced lesions of the anterior and posterior eye segment remained progressive. In conclusion, annual ivermectin treatments may prevent the emergence of ocular pathology in those populations still exposed to O.volvulus infection. Trial Registration: www.pactr.org PACTR201303000464219)

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Blindness and visual impairment due to age-related cataract in sub-Saharan Africa: a systematic review of recent population-based studies

Cited by 23 publications

References 35 publications

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

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

Number of People Blind or Visually Impaired by Cataract Worldwide and in World Regions, 1990 to 2010

Sustainable Control of Onchocerciasis: Ocular Pathology in Onchocerciasis Patients Treated Annually with Ivermectin for 23 Years: A Cohort Study

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