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The Lancet. Global Health Feb 2021Many causes of vision impairment can be prevented or treated. With an ageing global population, the demands for eye health services are increasing. We estimated the... (Meta-Analysis)
Meta-Analysis
Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study.
BACKGROUND
Many causes of vision impairment can be prevented or treated. With an ageing global population, the demands for eye health services are increasing. We estimated the prevalence and relative contribution of avoidable causes of blindness and vision impairment globally from 1990 to 2020. We aimed to compare the results with the World Health Assembly Global Action Plan (WHA GAP) target of a 25% global reduction from 2010 to 2019 in avoidable vision impairment, defined as cataract and undercorrected refractive error.
METHODS
We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. We fitted hierarchical models to estimate prevalence (with 95% uncertainty intervals [UIs]) of moderate and severe vision impairment (MSVI; presenting visual acuity from <6/18 to 3/60) and blindness (<3/60 or less than 10° visual field around central fixation) by cause, age, region, and year. Because of data sparsity at younger ages, our analysis focused on adults aged 50 years and older.
FINDINGS
Global crude prevalence of avoidable vision impairment and blindness in adults aged 50 years and older did not change between 2010 and 2019 (percentage change -0·2% [95% UI -1·5 to 1·0]; 2019 prevalence 9·58 cases per 1000 people [95% IU 8·51 to 10·8], 2010 prevalence 96·0 cases per 1000 people [86·0 to 107·0]). Age-standardised prevalence of avoidable blindness decreased by -15·4% [-16·8 to -14·3], while avoidable MSVI showed no change (0·5% [-0·8 to 1·6]). However, the number of cases increased for both avoidable blindness (10·8% [8·9 to 12·4]) and MSVI (31·5% [30·0 to 33·1]). The leading global causes of blindness in those aged 50 years and older in 2020 were cataract (15·2 million cases [9% IU 12·7-18·0]), followed by glaucoma (3·6 million cases [2·8-4·4]), undercorrected refractive error (2·3 million cases [1·8-2·8]), age-related macular degeneration (1·8 million cases [1·3-2·4]), and diabetic retinopathy (0·86 million cases [0·59-1·23]). Leading causes of MSVI were undercorrected refractive error (86·1 million cases [74·2-101·0]) and cataract (78·8 million cases [67·2-91·4]).
INTERPRETATION
Results suggest eye care services contributed to the observed reduction of age-standardised rates of avoidable blindness but not of MSVI, and that the target in an ageing global population was not reached.
FUNDING
Brien Holden Vision Institute, Fondation Théa, The Fred Hollows Foundation, Bill & Melinda Gates Foundation, Lions Clubs International Foundation, Sightsavers International, and University of Heidelberg.
Topics: Aged; Aged, 80 and over; Blindness; Cataract; Eye Diseases; Female; Glaucoma; Global Burden of Disease; Global Health; Humans; Macular Degeneration; Male; Middle Aged; Refractive Errors; Vision Disorders; Vision, Low; Visual Acuity
PubMed: 33275949
DOI: 10.1016/S2214-109X(20)30489-7 -
The Lancet. Global Health Dec 2017Contemporary data for causes of vision impairment and blindness form an important basis of recommendations in public health policies. Refreshment of the Global Vision... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Contemporary data for causes of vision impairment and blindness form an important basis of recommendations in public health policies. Refreshment of the Global Vision Database with recently published data sources permitted modelling of cause of vision loss data from 1990 to 2015, further disaggregation by cause, and forecasts to 2020.
METHODS
In this systematic review and meta-analysis, we analysed published and unpublished population-based data for the causes of vision impairment and blindness from 1980 to 2014. We identified population-based studies published before July 8, 2014, by searching online databases with no language restrictions (MEDLINE from Jan 1, 1946, and Embase from Jan 1, 1974, and the WHO Library Database). We fitted a series of regression models to estimate the proportion of moderate or severe vision impairment (defined as presenting visual acuity of <6/18 but ≥3/60 in the better eye) and blindness (presenting visual acuity of <3/60 in the better eye) by cause, age, region, and year.
FINDINGS
We identified 288 studies of 3 983 541 participants contributing data from 98 countries. Among the global population with moderate or severe vision impairment in 2015 (216·6 million [80% uncertainty interval 98·5 million to 359·1 million]), the leading causes were uncorrected refractive error (116·3 million [49·4 million to 202·1 million]), cataract (52·6 million [18·2 million to 109·6 million]), age-related macular degeneration (8·4 million [0·9 million to 29·5 million]), glaucoma (4·0 million [0·6 million to 13·3 million]), and diabetic retinopathy (2·6 million [0·2 million to 9·9 million]). Among the global population who were blind in 2015 (36·0 million [12·9 million to 65·4 million]), the leading causes were cataract (12·6 million [3·4 million to 28·7 million]), uncorrected refractive error (7·4 million [2·4 million to 14·8 million]), and glaucoma (2·9 million [0·4 million to 9·9 million]). By 2020, among the global population with moderate or severe vision impairment (237·1 million [101·5 million to 399·0 million]), the number of people affected by uncorrected refractive error is anticipated to rise to 127·7 million (51·0 million to 225·3 million), by cataract to 57·1 million (17·9 million to 124·1 million), by age-related macular degeneration to 8·8 million (0·8 million to 32·1 million), by glaucoma to 4·5 million (0·5 million to 15·4 million), and by diabetic retinopathy to 3·2 million (0·2 million to 12·9 million). By 2020, among the global population who are blind (38·5 million [13·2 million to 70·9 million]), the number of patients blind because of cataract is anticipated to rise to 13·4 million (3·3 million to 31·6 million), because of uncorrected refractive error to 8·0 million (2·5 million to 16·3 million), and because of glaucoma to 3·2 million (0·4 million to 11·0 million). Cataract and uncorrected refractive error combined contributed to 55% of blindness and 77% of vision impairment in adults aged 50 years and older in 2015. World regions varied markedly in the causes of blindness and vision impairment in this age group, with a low prevalence of cataract (<22% for blindness and 14·1-15·9% for vision impairment) and a high prevalence of age-related macular degeneration (>14% of blindness) as causes in the high-income subregions. Blindness and vision impairment at all ages in 2015 due to diabetic retinopathy (odds ratio 2·52 [1·48-3·73]) and cataract (1·21 [1·17-1·25]) were more common among women than among men, whereas blindness and vision impairment due to glaucoma (0·71 [0·57-0·86]) and corneal opacity (0·54 [0·43-0·66]) were more common among men than among women, with no sex difference related to age-related macular degeneration (0·91 [0·70-1·14]).
INTERPRETATION
The number of people affected by the common causes of vision loss has increased substantially as the population increases and ages. Preventable vision loss due to cataract (reversible with surgery) and refractive error (reversible with spectacle correction) continue to cause most cases of blindness and moderate or severe vision impairment in adults aged 50 years and older. A large scale-up of eye care provision to cope with the increasing numbers is needed to address avoidable vision loss.
FUNDING
Brien Holden Vision Institute.
Topics: Aging; Blindness; Cataract; Diabetic Retinopathy; Glaucoma; Global Health; Humans; Macular Degeneration; Prevalence; Visual Acuity
PubMed: 29032195
DOI: 10.1016/S2214-109X(17)30393-5 -
Investigative Ophthalmology & Visual... Apr 2020To determine the risk between degree of myopia and myopic macular degeneration (MMD), retinal detachment (RD), cataract, open angle glaucoma (OAG), and blindness. (Meta-Analysis)
Meta-Analysis
PURPOSE
To determine the risk between degree of myopia and myopic macular degeneration (MMD), retinal detachment (RD), cataract, open angle glaucoma (OAG), and blindness.
METHODS
A systematic review and meta-analyses of studies published before June 2019 on myopia complications. Odds ratios (OR) per complication and spherical equivalent (SER) degree (low myopia SER < -0.5 to > -3.00 diopter [D]; moderate myopia SER ≤ -3.00 to > -6.00 D; high myopia SER ≤ -6.00 D) were calculated using fixed and random effects models.
RESULTS
Low, moderate, and high myopia were all associated with increased risks of MMD (OR, 13.57, 95% confidence interval [CI], 6.18-29.79; OR, 72.74, 95% CI, 33.18-159.48; OR, 845.08, 95% CI, 230.05-3104.34, respectively); RD (OR, 3.15, 95% CI, 1.92-5.17; OR, 8.74, 95% CI, 7.28-10.50; OR, 12.62, 95% CI, 6.65-23.94, respectively); posterior subcapsular cataract (OR, 1.56, 95% CI, 1.32-1.84; OR, 2.55, 95% CI, 1.98-3.28; OR, 4.55, 95% CI, 2.66-7.75, respectively); nuclear cataract (OR, 1.79, 95% CI, 1.08-2.97; OR, 2.39, 95% CI, 1.03-5.55; OR, 2.87, 95% CI, 1.43-5.73, respectively); and OAG (OR, 1.59, 95% CI, 1.33-1.91; OR, 2.92, 95% CI, 1.89-4.52 for low and moderate/high myopia, respectively). The risk of visual impairment was strongly related to longer axial length, higher myopia degree, and age older than 60 years (OR, 1.71, 95% CI, 1.07-2.74; OR, 5.54, 95% CI, 3.12-9.85; and OR, 87.63, 95% CI, 34.50-222.58 for low, moderate, and high myopia in participants aged >60 years, respectively).
CONCLUSIONS
Although high myopia carries the highest risk of complications and visual impairment, low and moderate myopia also have considerable risks. These estimates should alert policy makers and health care professionals to make myopia a priority for prevention and treatment.
Topics: Age Factors; Cataract; Disease Progression; Female; Glaucoma, Open-Angle; Humans; Macular Degeneration; Male; Myopia, Degenerative; Prevalence; Prognosis; Risk Assessment; Visual Acuity
PubMed: 32347918
DOI: 10.1167/iovs.61.4.49 -
The Cochrane Database of Systematic... Nov 2022Perception is the ability to understand information from our senses. It allows us to experience and meaningfully interact with our environment. A stroke may impair... (Review)
Review
BACKGROUND
Perception is the ability to understand information from our senses. It allows us to experience and meaningfully interact with our environment. A stroke may impair perception in up to 70% of stroke survivors, leading to distress, increased dependence on others, and poorer quality of life. Interventions to address perceptual disorders may include assessment and screening, rehabilitation, non-invasive brain stimulation, pharmacological and surgical approaches.
OBJECTIVES
To assess the effectiveness of interventions aimed at perceptual disorders after stroke compared to no intervention or control (placebo, standard care, attention control), on measures of performance in activities of daily living. SEARCH METHODS: We searched the trials registers of the Cochrane Stroke Group, CENTRAL, MEDLINE, Embase, and three other databases to August 2021. We also searched trials and research registers, reference lists of studies, handsearched journals, and contacted authors.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) of adult stroke survivors with perceptual disorders. We defined perception as the specific mental functions of recognising and interpreting sensory stimuli and included hearing, taste, touch, smell, somatosensation, and vision. Our definition of perception excluded visual field deficits, neglect/inattention, and pain.
DATA COLLECTION AND ANALYSIS
One review author assessed titles, with two review authors independently screening abstracts and full-text articles for eligibility. One review author extracted, appraised, and entered data, which were checked by a second author. We assessed risk of bias (ROB) using the ROB-1 tool, and quality of evidence using GRADE. A stakeholder group, comprising stroke survivors, carers, and healthcare professionals, was involved in this review update.
MAIN RESULTS
We identified 18 eligible RCTs involving 541 participants. The trials addressed touch (three trials, 70 participants), somatosensory (seven trials, 196 participants) and visual perception disorders (seven trials, 225 participants), with one (50 participants) exploring mixed touch-somatosensory disorders. None addressed stroke-related hearing, taste, or smell perception disorders. All but one examined the effectiveness of rehabilitation interventions; the exception evaluated non-invasive brain stimulation. For our main comparison of active intervention versus no treatment or control, one trial reported our primary outcome of performance in activities of daily living (ADL): Somatosensory disorders: one trial (24 participants) compared an intervention with a control intervention and reported an ADL measure. Touch perception disorder: no trials measuring ADL compared an intervention with no treatment or with a control intervention. Visual perception disorders: no trials measuring ADL compared an intervention with no treatment or control. In addition, six trials reported ADL outcomes in a comparison of active intervention versus active intervention, relating to somatosensation (three trials), touch (one trial) and vision (two trials). AUTHORS' CONCLUSIONS: Following a detailed, systematic search, we identified limited RCT evidence of the effectiveness of interventions for perceptual disorders following stroke. There is insufficient evidence to support or refute the suggestion that perceptual interventions are effective. More high-quality trials of interventions for perceptual disorders in stroke are needed. They should recruit sufficient participant numbers, include a 'usual care' comparison, and measure longer-term functional outcomes, at time points beyond the initial intervention period. People with impaired perception following a stroke should continue to receive neurorehabilitation according to clinical guidelines.
Topics: Adult; Humans; Activities of Daily Living; Perceptual Disorders; Stroke; Stroke Rehabilitation; Vision Disorders; Randomized Controlled Trials as Topic
PubMed: 36326118
DOI: 10.1002/14651858.CD007039.pub3 -
Neurology. Clinical Practice Jun 2016To summarize the literature on Alice in Wonderland syndrome (AIWS), a disorder characterized by distortions of visual perception, the body schema, and the experience of... (Review)
Review
PURPOSE OF REVIEW
To summarize the literature on Alice in Wonderland syndrome (AIWS), a disorder characterized by distortions of visual perception, the body schema, and the experience of time.
RECENT FINDINGS
On the basis of 169 published case descriptions, the etiology of AIWS is divided into 8 main groups, with neurologic disorders affecting mostly adults and elderly patients and encephalitides affecting mostly patients aged ≤18 years. Symptoms of AIWS are also experienced in the general population, with up to 30% of adolescents reporting nonclinical symptoms.
SUMMARY
In clinical cases of AIWS, auxiliary investigations (including blood tests, EEG, and brain MRI) are strongly advised. Treatment should be directed at the suspected underlying condition, although reassurance that the symptoms themselves are not harmful seems to suffice in about 50% of the cases. International classifications such as the DSM and ICD should consider placing the syndrome on their research agenda.
PubMed: 27347442
DOI: 10.1212/CPJ.0000000000000251 -
Frontiers in Public Health 2023The rising prevalence of myopia is a major global public health concern. Economic evaluation of myopia interventions is critical for maximizing the benefits of treatment... (Review)
Review
The rising prevalence of myopia is a major global public health concern. Economic evaluation of myopia interventions is critical for maximizing the benefits of treatment and the healthcare system. This systematic review aimed to evaluate the cost-effectiveness of interventions for treating myopia. Five databases were searched - Embase, Emcare, PubMed, Web of Science, and ProQuest - from inception to July 2022 and a total of 2,099 articles were identified. After careful assessments, 6 studies met the eligibility criteria. The primary outcomes of this systematic review were costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). The secondary outcomes included utility values and net monetary benefits (NMB). One study determined the cost-effectiveness of photorefractive screening plus treatment with 0.01% atropine, 2 studies examined cost-effectiveness of corneal refractive surgery, and 3 studies evaluated cost-effectiveness of commonly used therapies for pathologic myopia. Corneal refractive surgeries included laser keratomileusis (LASIK), femtosecond laser-assisted keratomileusis (FS-LASIK), photorefractive keratectomy (PRK), and small-incision lenticule extraction (SMILE). Interventions for pathologic myopia included ranibizumab, conbercept, and photodynamic therapy (PDT). At an incremental cost of NZ$ 18 (95% CI 15, 20) (US$ 11) per person, photorefractive screening plus 0.01% atropine resulted in an ICER of NZ$ 1,590/QALY (US$ 1,001/QALY) (95% CI NZ$ 1,390, 1,791) for an incremental QALY of 0.0129 (95% CI 0.0127, 0.0131). The cost of refractive surgery in Europe ranged from €3,075 to €3,123 ([US$4,046 to $4,109 - adjusted to 2021 inflation). QALYs associated with these procedures were 23 (FS-LASIK) and 24 (SMILE and PRK) with utility values of 0.8 and ICERs ranging from approximately €14 (US$17)/QALY to €19 (US$23)/QALY. The ICER of LASIK was US$683/diopter gained (inflation-adjusted). The ICER of ranibizumab and PDT were £8,778 (US$12,032)/QALY and US$322,460/QALY respectively, with conbercept yielding a saving of 541,974 RMB (US$80,163)/QALY, respectively. The use of 0.01% atropine and corneal refractive surgery were cost-effective for treating myopia. Treating pathologic myopia with ranibizumab and conbercept were more cost-effective than PDT. Prevention of myopia progression is more cost-effective than treating pathologic myopia.
Topics: Humans; Visual Acuity; Cost-Effectiveness Analysis; Ranibizumab; Myopia; Atropine Derivatives
PubMed: 36923029
DOI: 10.3389/fpubh.2023.1093836 -
Ophthalmic & Physiological Optics : the... Nov 2017Blue-blocking (BB) spectacle lenses, which attenuate short-wavelength light, are being marketed to alleviate eyestrain and discomfort when using digital devices, improve... (Review)
Review
PURPOSE
Blue-blocking (BB) spectacle lenses, which attenuate short-wavelength light, are being marketed to alleviate eyestrain and discomfort when using digital devices, improve sleep quality and potentially confer protection from retinal phototoxicity. The aim of this review was to investigate the relative benefits and potential harms of these lenses.
METHODS
We included randomised controlled trials (RCTs), recruiting adults from the general population, which investigated the effect of BB spectacle lenses on visual performance, symptoms of eyestrain or eye fatigue, changes to macular integrity and subjective sleep quality. We searched MEDLINE, EMBASE, the Cochrane Library and clinical trial registers, until 30 April 2017. Risk of bias was assessed using the Cochrane tool.
RESULTS
Three studies (with 136 participants) met our inclusion criteria; these had limitations in study design and/or implementation. One study compared the effect of BB lenses with clear lenses on contrast sensitivity (CS) and colour vision (CV) using a pseudo-RCT crossover design; there was no observed difference between lens types (log CS; Mean Difference (MD) = -0.01 [-0.03, 0.01], CV total error score on 100-hue; MD = 1.30 [-7.84, 10.44]). Another study measured critical fusion frequency (CFF), as a proxy for eye fatigue, on wearers of low and high BB lenses, pre- and post- a two-hour computer task. There was no observed difference between low BB and standard lens groups, but there was a less negative change in CFF between the high and low BB groups (MD = 1.81 [0.57, 3.05]). Both studies compared eyestrain symptoms with Likert scales. There was no evidence of inter-group differences for either low BB (MD = 0.00 [-0.22, 0.22]) or high BB lenses (MD = -0.05 [-0.31, 0.21]), nor evidence of a difference in the proportion of participants showing an improvement in symptoms of eyestrain or eye fatigue. One study reported a small improvement in sleep quality in people with self-reported insomnia after wearing high compared to low-BB lenses (MD = 0.80 [0.17, 1.43]) using a 10-point Likert scale. A study involving normal participants found no observed difference in sleep quality. We found no studies investigating effects on macular structure or function.
CONCLUSIONS
We find a lack of high quality evidence to support using BB spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.
Topics: Circadian Rhythm; Contrast Sensitivity; Eye Pain; Eyeglasses; Humans; Light; Macula Lutea; Randomized Controlled Trials as Topic; Sleep; Sleep Initiation and Maintenance Disorders; Visual Acuity
PubMed: 29044670
DOI: 10.1111/opo.12406 -
The Cochrane Database of Systematic... Sep 2021The clinical management of intermittent exotropia (X(T)) has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The clinical management of intermittent exotropia (X(T)) has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for intervention, the most effective form of treatment, and whether there is an optimal time in the evolution of the disease at which any given treatment should be carried out.
OBJECTIVES
The objective of this review was to analyze the effects of various surgical and non-surgical treatments in randomized controlled trials (RCTs) of participants with intermittent exotropia, and to report intervention criteria and determine whether the treatment effect varies by age and subtype of X(T).
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 1), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Science Information database (LILACS); the ISRCTN registry; ClinicalTrials.gov, and the WHO ICTRP. The date of the search was 20 January 2021. We performed manual searches of the British Orthoptic Journal up to 2002, and the proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA), and American Association for Pediatric Ophthalmology and Strabismus meeting (AAPOS) up to 2001.
SELECTION CRITERIA
We included RCTs of any surgical or non-surgical treatment for intermittent exotropia.
DATA COLLECTION AND ANALYSIS
We followed standard Cochrane methodology.
MAIN RESULTS
We included six RCTs, four of which took place in the United States, and the remaining two in Asia (Turkey, India). A total of 890 participants with basic or distance X(T) were included, most of whom were children aged 12 months to 10 years. Three of these six studies were from the 2013 version of this review. Overall, the included studies had a high risk of performance bias as masking of participants and personnel administering treatment was not possible. Two RCTs compared bilateral lateral rectus recession versus unilateral lateral rectus recession with medial rectus resection, but only one RCT (n = 197) reported on the primary outcomes of this review. Bilateral lateral rectus recession likely results in little difference in motor alignment at near (MD 1.00, 95% CI -2.69 to 4.69) and distance (MD 2.00, 95% CI -1.22 to 5.22) fixation as measured in pupillary distance using PACT (moderate-certainty evidence). Bilateral lateral rectus recession may result in little to no difference in stereoacuity at near fixation (risk ratio (RR) 0.77, 95% CI 0.35 to 1.71), adverse events (RR 7.36, 95% CI 0.39 to 140.65), or quality of life measures (low-certainty evidence). We conducted a meta-analysis of two RCTs comparing patching (n = 249) with active observation (n = 252), but were unable to conduct further meta-analyses due to the clinical and methodological heterogeneity in the remaining trials. We found evidence that patching was clinically more effective than active observation in improving motor alignment at near (mean difference (MD) -2.23, 95% confidence interval (CI) -4.02 to -0.44) and distance (MD -2.00, 95% CI -3.40 to -0.61) fixation as measured by prism and alternate cover test (PACT) at six months (high-certainty evidence). The evidence suggests that patching results in little to no difference in stereoacuity at near fixation (MD 0.00, 95% CI -0.07 to 0.07) (low-certainty evidence). Stereoacuity at distance, motor fusion test, and quality of life measures were not reported. Adverse events were also not reported, but study authors explained that they were not anticipated due to the non-surgical nature of patching. One RCT (n = 38) compared prism adaptation test with eye muscle surgery versus eye muscle surgery alone. No review outcomes were reported. One RCT (n = 60) compared lateral rectus recession and medial rectus plication versus lateral rectus recession and medial rectus resection. Lateral rectus recession and medial rectus plication may not improve motor alignment at distance (MD 0.66, 95% CI -1.06 to 2.38) (low-certainty evidence). The evidence for the effect of lateral rectus recession and medial rectus plication on motor fusion test performance is very uncertain (RR 0.92, 95% CI 0.48 to 1.74) (very low-certainty evidence).
AUTHORS' CONCLUSIONS
Patching confers a clinical benefit in children aged 12 months to 10 years of age with basic- or distance-type X(T) compared with active observation. There is insufficient evidence to determine whether interventions such as bilateral lateral rectus recession versus unilateral lateral rectus recession with medial rectus resection; lateral rectus recession and medial rectus plication versus lateral rectus recession and medial rectus resection; and prism adaptation test prior to eye muscle surgery versus eye muscle surgery alone may confer any benefit.
Topics: Asia; Child; Exotropia; Humans; Oculomotor Muscles; Strabismus; Visual Acuity
PubMed: 34516656
DOI: 10.1002/14651858.CD003737.pub4 -
The Lancet. Global Health Feb 2021To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990-2020, and forecasts for 2050.
METHODS
We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision
visual acuity is ≥6/12). We forecast estimates of vision loss up to 2050. FINDINGS
In 2020, an estimated 43·3 million (95% UI 37·6-48·4) people were blind, of whom 23·9 million (55%; 20·8-26·8) were estimated to be female. We estimated 295 million (267-325) people to have moderate and severe vision impairment, of whom 163 million (55%; 147-179) were female; 258 million (233-285) to have mild vision impairment, of whom 142 million (55%; 128-157) were female; and 510 million (371-667) to have visual impairment from uncorrected presbyopia, of whom 280 million (55%; 205-365) were female. Globally, between 1990 and 2020, among adults aged 50 years or older, age-standardised prevalence of blindness decreased by 28·5% (-29·4 to -27·7) and prevalence of mild vision impairment decreased slightly (-0·3%, -0·8 to -0·2), whereas prevalence of moderate and severe vision impairment increased slightly (2·5%, 1·9 to 3·2; insufficient data were available to calculate this statistic for vision impairment from uncorrected presbyopia). In this period, the number of people who were blind increased by 50·6% (47·8 to 53·4) and the number with moderate and severe vision impairment increased by 91·7% (87·6 to 95·8). By 2050, we predict 61·0 million (52·9 to 69·3) people will be blind, 474 million (428 to 518) will have moderate and severe vision impairment, 360 million (322 to 400) will have mild vision impairment, and 866 million (629 to 1150) will have uncorrected presbyopia.
INTERPRETATION
Age-adjusted prevalence of blindness has reduced over the past three decades, yet due to population growth, progress is not keeping pace with needs. We face enormous challenges in avoiding vision impairment as the global population grows and ages.
FUNDING
Brien Holden Vision Institute, Fondation Thea, Fred Hollows Foundation, Bill & Melinda Gates Foundation, Lions Clubs International Foundation, Sightsavers International, and University of Heidelberg.
Topics: Aged; Aged, 80 and over; Blindness; Cataract; Eye Diseases; Female; Forecasting; Glaucoma; Global Burden of Disease; Global Health; Humans; Macular Degeneration; Male; Middle Aged; Presbyopia; Vision, Low; Visual Acuity
PubMed: 33275950
DOI: 10.1016/S2214-109X(20)30425-3 -
The Lancet. Global Health Sep 2017Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global estimates, trends, and projections of global blindness and vision impairment.
METHODS
We did a systematic review and meta-analysis of population-based datasets relevant to global vision impairment and blindness that were published between 1980 and 2015. We fitted hierarchical models to estimate the prevalence (by age, country, and sex), in 2015, of mild visual impairment (presenting visual acuity worse than 6/12 to 6/18 inclusive), moderate to severe visual impairment (presenting visual acuity worse than 6/18 to 3/60 inclusive), blindness (presenting visual acuity worse than 3/60), and functional presbyopia (defined as presenting near vision worse than N6 or N8 at 40 cm when best-corrected distance visual acuity was better than 6/12).
FINDINGS
Globally, of the 7·33 billion people alive in 2015, an estimated 36·0 million (80% uncertainty interval [UI] 12·9-65·4) were blind (crude prevalence 0·48%; 80% UI 0·17-0·87; 56% female), 216·6 million (80% UI 98·5-359·1) people had moderate to severe visual impairment (2·95%, 80% UI 1·34-4·89; 55% female), and 188·5 million (80% UI 64·5-350·2) had mild visual impairment (2·57%, 80% UI 0·88-4·77; 54% female). Functional presbyopia affected an estimated 1094·7 million (80% UI 581·1-1686·5) people aged 35 years and older, with 666·7 million (80% UI 364·9-997·6) being aged 50 years or older. The estimated number of blind people increased by 17·6%, from 30·6 million (80% UI 9·9-57·3) in 1990 to 36·0 million (80% UI 12·9-65·4) in 2015. This change was attributable to three factors, namely an increase because of population growth (38·4%), population ageing after accounting for population growth (34·6%), and reduction in age-specific prevalence (-36·7%). The number of people with moderate and severe visual impairment also increased, from 159·9 million (80% UI 68·3-270·0) in 1990 to 216·6 million (80% UI 98·5-359·1) in 2015.
INTERPRETATION
There is an ongoing reduction in the age-standardised prevalence of blindness and visual impairment, yet the growth and ageing of the world's population is causing a substantial increase in number of people affected. These observations, plus a very large contribution from uncorrected presbyopia, highlight the need to scale up vision impairment alleviation efforts at all levels.
FUNDING
Brien Holden Vision Institute.
Topics: Blindness; Global Health; Humans; Prevalence; Vision Disorders; Visual Acuity
PubMed: 28779882
DOI: 10.1016/S2214-109X(17)30293-0