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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 Medical Clinics of North America May 2021Age-related macular degeneration (AMD) is a leading cause of blindness. The main risk factor is advancing age, with the severity of vision loss ranging from mild to... (Review)
Review
Age-related macular degeneration (AMD) is a leading cause of blindness. The main risk factor is advancing age, with the severity of vision loss ranging from mild to severe. There is a 25% risk of early AMD and 8% risk of late AMD in patients over the age of 75, with the number of cases expected to increase because of the aging population. Diagnosis of the disease requires a dilated fundus examination. Physicians should be aware of the symptoms, risk factors, and treatment options for AMD to refer appropriately for ophthalmologic evaluation. Early detection can be helpful to prevent disease progression.
Topics: Blindness; Humans; Macular Degeneration; Risk Factors; Sensory Aids; Vision, Low
PubMed: 33926642
DOI: 10.1016/j.mcna.2021.01.003 -
Cell Jan 2022Methods to deliver gene editing agents in vivo as ribonucleoproteins could offer safety advantages over nucleic acid delivery approaches. We report the development and...
Methods to deliver gene editing agents in vivo as ribonucleoproteins could offer safety advantages over nucleic acid delivery approaches. We report the development and application of engineered DNA-free virus-like particles (eVLPs) that efficiently package and deliver base editor or Cas9 ribonucleoproteins. By engineering VLPs to overcome cargo packaging, release, and localization bottlenecks, we developed fourth-generation eVLPs that mediate efficient base editing in several primary mouse and human cell types. Using different glycoproteins in eVLPs alters their cellular tropism. Single injections of eVLPs into mice support therapeutic levels of base editing in multiple tissues, reducing serum Pcsk9 levels 78% following 63% liver editing, and partially restoring visual function in a mouse model of genetic blindness. In vitro and in vivo off-target editing from eVLPs was virtually undetected, an improvement over AAV or plasmid delivery. These results establish eVLPs as promising vehicles for therapeutic macromolecule delivery that combine key advantages of both viral and nonviral delivery.
Topics: Animals; Base Sequence; Blindness; Brain; DNA; Disease Models, Animal; Drug Delivery Systems; Fibroblasts; Gene Editing; Genetic Engineering; HEK293 Cells; Humans; Liver; Mice; Mice, Inbred C57BL; Proprotein Convertase 9; Proteins; Retinal Pigment Epithelium; Retroviridae; Virion; Vision, Ocular
PubMed: 35021064
DOI: 10.1016/j.cell.2021.12.021 -
The Lancet. Global Health Apr 2021
Review
Topics: Advisory Committees; Blindness; Cost of Illness; Eye Diseases; Global Burden of Disease; Global Health; Health Services Accessibility; Humans; Quality of Health Care; Quality of Life; Sustainable Development
PubMed: 33607016
DOI: 10.1016/S2214-109X(20)30488-5 -
Molecular Aspects of Medicine Aug 2023Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output... (Review)
Review
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
Topics: Humans; Intraocular Pressure; Neuroprotection; Neurodegenerative Diseases; Glaucoma; Retinal Ganglion Cells; Blindness
PubMed: 37331129
DOI: 10.1016/j.mam.2023.101193 -
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
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 -
Nature Medicine Jun 2022Causes of blindness differ across the globe; in higher-income countries, most blindness results from the degeneration of specific classes of cells in the retina,... (Review)
Review
Causes of blindness differ across the globe; in higher-income countries, most blindness results from the degeneration of specific classes of cells in the retina, including retinal pigment epithelium (RPE), photoreceptors, and retinal ganglion cells. Advances over the past decade in retinal regenerative medicine have allowed each of these cell types to be produced ex vivo from progenitor stem cells. Here, we review progress in applying these technologies to cell replacement - with the goal of vision restoration in degenerative disease. We discuss the landscape of human clinical trials for RPE transplantation and advanced preclinical studies for other cell types. We also review progress toward in situ repair of retinal degeneration using endogenous progenitor cells. Finally, we provide a high-level overview of progress toward prosthetic ocular vision restoration, including advanced photovoltaic devices, opsin-based gene therapy, and small-molecule photoswitches. Progress in each of these domains is at or near the human clinical-trial stage, bringing the audacious goal of vision restoration within sight.
Topics: Blindness; Humans; Regenerative Medicine; Retina; Retinal Degeneration; Retinal Pigment Epithelium; Stem Cell Transplantation
PubMed: 35715505
DOI: 10.1038/s41591-022-01862-8 -
Genes Aug 2021Leber's congenital amaurosis (LCA), one of the most severe inherited retinal dystrophies, is typically associated with extremely early onset of visual loss, nystagmus,... (Review)
Review
Leber's congenital amaurosis (LCA), one of the most severe inherited retinal dystrophies, is typically associated with extremely early onset of visual loss, nystagmus, and amaurotic pupils, and is responsible for 20% of childhood blindness. With advances in molecular diagnostic technology, the knowledge about the genetic background of LCA has expanded widely, while disease-causing variants have been identified in 38 genes. Different pathogenetic mechanisms have been found among these varieties of genetic mutations, all of which result in the dysfunction or absence of their encoded proteins participating in the visual cycle. Hence, the clinical phenotypes also exhibit extensive heterogenicity, including the course of visual impairment, involvement of the macular area, alteration in retinal structure, and residual function of the diseased photoreceptor. By reviewing the clinical course, fundoscopic images, optical coherent tomography examination, and electroretinogram, genotype-phenotype correlations could be established for common genetic mutations in LCA, which would benefit the timing of the diagnosis and thus promote early intervention. Gene therapy is promising in the management of LCA, while several clinical trials are ongoing and preliminary success has been announced, focusing on RPE65 and other common disease-causing genes. This review provides an update on the genetics, clinical examination findings, and genotype-phenotype correlations in the most well-established causative genetic mutations of LCA.
Topics: Blindness; Genetic Association Studies; Genetic Predisposition to Disease; Humans; Leber Congenital Amaurosis; Mutation; Retina; Retinal Dystrophies; cis-trans-Isomerases
PubMed: 34440435
DOI: 10.3390/genes12081261 -
The Lancet. Public Health Dec 2020Vision loss is an important public health issue in China, but a detailed understanding of national and regional trends in its prevalence and causes, which could inform...
BACKGROUND
Vision loss is an important public health issue in China, but a detailed understanding of national and regional trends in its prevalence and causes, which could inform health policy, has not been available. This study aimed to assess the prevalence, causes, and regional distribution of vision impairment and blindness in China in 1990 and 2019.
METHODS
Data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used to estimate the prevalence of moderate and severe vision impairment and blindness in China and compare with other Group of 20 (G20) countries. We used GBD methodology to systematically analyse all available demographic and epidemiological data at the provincial level in China. We compared the age-standardised prevalences across provinces, and the changes in proportion of vision loss attributable to various eye diseases in 1990 and 2019. We used two different counterfactual scenarios with respect to population structure and age-specific prevalence to assess the contribution of population growth and ageing to trends in vision loss.
FINDINGS
In 2019, the age-standardised prevalence was 2·57% (uncertainty interval [UI] 2·28-2·86) for moderate vision impairment, 0·25% (0·22-0·29) for severe vision impairment, and 0·48% (0·43-0·54) for blindness in China, which were all below the global average, but the prevalence of moderate and severe vision impairment had increased more rapidly than in other G20 countries from 1990 to 2019. The prevalence of vision loss increased with age, and the main causes of vision loss varied across age groups. The leading causes of vision impairment in China were uncorrected refractive error, cataract, and macular degeneration in both 1990 and 2019 in the overall population. From 1990 to 2019, the number of people with moderate vision impairment increased by 133·67% (from 19·65 to 45·92 million), those with severe vision impairment increased by 147·14% (from 1·89 to 4·67 million), and those with blindness increased by 64·35% (from 5·29 to 8·69 million); in each case, 20·16% of the increase could be explained by population growth. The contributions to these changes by population ageing were 87·22% for moderate vision impairment, 116·06% for severe vision impairment, and 99·22% for blindness, and the contributions by age-specific prevalence were 26·29% for moderate vision impairment, 10·91% for severe vision impairment, and -55·04% for blindness. The prevalence and specific causes of vision loss differed across provinces.
INTERPRETATION
Although a comprehensive national policy to prevent blindness is in place, public awareness of visual health needs improving, and reducing the prevalence of moderate and severe vision impairment should be prioritised in future work.
FUNDING
China National Key Research and Development Programme and Beijing Municipal Special Funds for Medical Research on Public Welfare Development and Reform.
Topics: Adolescent; Adult; Age Factors; Aged; Aging; Blindness; Cataract; Child; Child, Preschool; China; Female; Global Burden of Disease; Global Health; Humans; Macular Degeneration; Male; Middle Aged; Prevalence; Refractive Errors; Risk Factors; Severity of Illness Index; Young Adult
PubMed: 33271081
DOI: 10.1016/S2468-2667(20)30254-1 -
Vision Research Nov 2022Stereopsis provides us with a vivid impression of the depth and distance of objects in our 3- dimensional world. Stereopsis is important for a number of everyday visual... (Review)
Review
Stereopsis provides us with a vivid impression of the depth and distance of objects in our 3- dimensional world. Stereopsis is important for a number of everyday visual tasks, including (but not limited to) reaching and grasping, fine visuo-motor control, and navigating in our world. This review briefly discusses the neural substrate for normal binocular vision and stereopsis and its development in primates; outlines some of the issues and limitations of stereopsis tests and examines some of the factors that limit the typical development of stereopsis and the causes and consequences of stereo-deficiency and stereo-blindness. Finally, we review several approaches to improving or recovering stereopsis in both neurotypical individuals and those with stereo-deficiency and stereo-blindness and outline some emerging strategies for improving stereopsis.
Topics: Animals; Blindness; Depth Perception; Learning; Vision, Binocular
PubMed: 35841717
DOI: 10.1016/j.visres.2022.108082