Effect of providing near glasses on productivity among rural Indian tea workers with presbyopia (PROSPER): a randomised trial

Strategies to address inequity of uncorrected refractive error in the Western Pacific: A modified Delphi process

PURPOSE

Uncorrected refractive error is the leading cause of vision impairment globally; however, little attention has been given to equity and access to services. This study aimed to identify and prioritise: (1) strategies to address inequity of access to refractive error services and (2) population groups to target with these strategies in five sub-regions within the Western Pacific.

METHODS

We invited eye care professionals to complete a two-round online prioritisation process. In round 1, panellists nominated population groups least able to access refractive error services, and strategies to improve access. Responses were summarised and presented in round 2, where panellists ranked the groups (by extent of difficulty and size) and strategies (in terms of reach, acceptability, sustainability, feasibility and equity). Groups and strategies were scored according to their rank within each sub-region.

RESULTS

Seventy five people from 17 countries completed both rounds (55% women). Regional differences were evident. Indigenous peoples were a priority group for improving access in Australasia and Southeast Asia, while East Asia identified refugees and Oceania identified rural/remote people. Across the five sub-regions, reducing out-of-pocket costs was a commonly prioritised strategy for refraction and spectacles. Australasia prioritised improving cultural safety, East Asia prioritised strengthening school eye health programmes and Oceania and Southeast Asia prioritised outreach to rural areas.

CONCLUSION

These results provide policy-makers, researchers and funders with a starting point for context-specific actions to improve access to refractive error services, particularly among underserved population groups who may be left behind in existing private sector-dominated models of care.

The burden, causes, and determinants of blindness and vision impairment in Asia: An analysis of the Global Burden of Disease Study

Background

Asia accounts for more than half of the world's population and carries a substantial proportion of the global burden of blindness and vision impairment. Characterising this burden, as well as its causes and determinants, could help with devising targeted interventions for reducing the occurrence of blindness and visual impairment.

Methods

Using the Global Burden of Disease Study 2019 database, we retrieved data on the number of disability-adjusted life years (DALYs); crude and age-standardised rates; and the prevalence (with 95% uncertainty intervals (95%UIs)) of blindness and vision loss due to six causes (age-related macular degeneration, cataracts, glaucoma, near-vision impairment, refractive error, and other vision loss) for Asian countries for the period between 1990 and 2019. We defined DALYs as the sum of the years lost due to disability and years of life lost, and calculated age-standardised figures for the number of DALYs and prevalence by adjusting for population size and age structure. We then evaluated the time trend of the disease burden and conducted subgroup analyses by gender, age, geographic locations, and socio-demographic index (SDI).

Results

In 2019, the DALYs and prevalence of blindness and vision loss had risen by 90.1% and 116% compared with 1990, reaching 15.84 million DALYs (95% UI = 15.83, 15.85) and 506.71 million cases (95% UI = 506.68, 506.74). Meanwhile, the age-standardised rate of DALYs decreased from 1990 to 2019. Cataracts, refractive error, and near vision impairment were the three most common causes. South Asia had the heaviest regional disease burden (age-standardised rate of DALYs = 517 per 100 000 population; 95% UI = 512, 521). Moreover, the burden due to cataracts ranked high in most Asian populations. Being a woman; being older; and having a lower national SDI were factors associated with a greater vision loss burden.

Conclusions

The burden due to vision loss remains high in Asian populations. Cataracts, refractive error, and near vision loss were the primary causes of blindness and vision loss. Greater investment in ocular disease prevention and care by countries with lower socioeconomic status is needed, as well as specific strategies targeting cataract management, women and the elderly.

Near vision impairment and effective refractive error coverage for near vision in Andhra Pradesh, India - The Akividu Visual Impairment Study (AVIS)

CLINICAL RELEVANCE

Near Vision Impairment (NVI) is common in developing countries. A substantial proportion of NVI can be addressed by providing spectacles. Innovative eye care programmes are needed to address NVI. Population-based epidemiological studies can provide vital data to plan such eye care service delivery models.

BACKGROUND

To report the prevalence of NVI and effective Refractive Error Coverage (eREC) for near vision in West Godavari and Krishna districts in Andhra Pradesh, south India.

METHODS

A population-based cross-sectional study was carried out using a Rapid Assessment of Visual Impairment methodology. Presenting and pinhole distance visual acuity were assessed followed by near vision assessment using a N notation chart at a fixed distance of 40 cm. If the presenting near vision was worse than N8, the best corrected near visual acuity was recorded with age appropriate near vision correction. NVI was defined as presenting near vision worse than N8 among those without distance vision impairment (6/18 or better in the better eye). Effective Refractive Error Coverage for near was calculated as the proportion of individuals with an adequate correction to the total participants, including those with inadequate, adequate, and no correction for near vision.

RESULTS

Data of 2,228 participants aged ≥40 years were analysed. The mean age of these participants was 54.0 ± 10.4 years; 53.8% were women; 44.5% had no formal education. The prevalence of NVI was 27.1% (95% CI: 25.2-29.0%). NVI significantly associated with 70 and above age group (adjusted OR: 1.97; 95% CI: 1.45-3.70). Participants with formal education had lower odds for NVI (adjusted OR: 0.75; 95 % CI: 0.68-0.83). The eREC for near vision was 48.0%.

CONCLUSION

NVI affects over a quarter of people aged ≥40 years in the West Godavari and Krishna districts of Andhra Pradesh. However, eREC is under 50% and there is scope for improving this by establishing eye care services to achieve universal eye health for all.

BCLA CLEAR Presbyopia: Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

The effect on income of providing near vision correction to workers in Bangladesh: The THRIVE (Tradespeople and Hand-workers Rural Initiative for a Vision-enhanced Economy) randomized controlled trial

INTRODUCTION

Presbyopia, the leading cause of vision impairment globally, is common during working years. However, no trials have assessed presbyopia's impact on income.

METHODS

In April 2017, we conducted a census among 59 Bangladesh villages to identify persons aged 35 to 65 years with presbyopia (presenting distance vision > = 6/12 bilaterally and correctable inability to see 6/13 at 40 cm with both eyes), who never had owned glasses. Participants were randomized (1:1) to receive immediate free reading glasses (intervention) or glasses delivered 8 months later (control). Visual demand of different jobs was stratified into three levels. Outcomes were between-group differences in the 8 month change in: self-reported monthly income (primary) and Near Vision Related Quality of Life (NVRQOL, secondary).

RESULTS

Among 10,884 census participants, 3,655 (33.6%) met vision criteria and 863 (23.6%) comprised a sample enriched for near vision-intensive jobs, but 39 (4.52%) could not be reached. All participants allocated to intervention (n = 423, 51.3%) and control (n = 401, 48.7%) received the appropriate intervention, and follow-up was available for 93.4% and 96.8% respectively. Groups were similar at baseline in all characteristics: mean age was 47 years, 50% were male, 35% literate, and about half engaged in "most near vision-intensive" occupations. Glasses wear at 8-month follow-up was 88.3% and 7.81% in intervention and control respectively. At baseline, both the intervention and control groups had a self-reported median monthly income of US$35.3. At endline, the median income for the intervention group was US$47.1 compared with US$35.3 for control, a difference of 33.4%. Predictors of greater income increase in multivariate models included intervention group allocation (OR 1.45, 95% CI 1.12, 1.88, P = 0.005), male sex (OR 2.41, 95% CI 1.84, 3.16, P <0.001), and not engaging in income-producing work at baseline (OR 2.35, 95% CI 1.69, 3.26, P<0.001).

CONCLUSION

Provision of reading glasses increases income in near vision-intensive occupations, and may facilitate return to work for those currently unemployed.

Evaluation of a telemedicine-enabled universal eye health delivery model in rural southern India

OBJECTIVES

To evaluate the accuracy of tele-ophthalmic examination (TOE) for common ocular conditions in comparison with the gold-standard in-person examination (IPE) for diagnosis and treatment advice.

METHODS

In a prospective, diagnostic accuracy validation study, we recruited 339 consecutive new patients, aged ≥16 years, visiting a vision centre (VC) associated with Aravind Eye Hospital in south India during January and February, 2020. All participants underwent the TOE, followed by IPE on the same visit. The in-person ophthalmologist was masked to the TOE diagnosis and treatment advice. Data were analysed via the sensitivity specificity of TOE versus the gold-standard IPE.

RESULTS

TOE achieved high sensitivity and specificity for identifying normal eyes with 87.4% and 93.5%, respectively. TOE had high sensitivity for cataracts (91.7%), infective conjunctivitis (72.2%), and moderate sensitivity for pterygium (62.5%), DR (57.1%), non-serious injury (41.7%), but low sensitivity for glaucoma (12.5%). TOE had high specificity ranging from 93.5% to 99.8% for all diagnoses. The sensitivity for treatment advice ranged from 58.1% to 77.2% and specificity from 96.9% to 100%.

CONCLUSIONS

The TOE in VCs has acceptable accuracy to an IPE by an ophthalmologist for correctly identifying and treating major eye ailments. Through providing universal eye care to rural populations, this model may contribute to work toward achieving Universal Health Coverage, which is a linchpin of the health-related U.N. Sustainable Development Goals (SDG).

Uncorrected Refractive Error in the African American Eye Disease Study

Importance

Refractive error remains the largest cause of correctable visual impairment in the US. Correction of refractive error will reduce visual impairment and its associated morbidity but also improve quality of life and productivity.

Objective

To determine the burden of and risk factors (RFs) associated with any uncorrected refractive error (UCRE) and unmet refractive need (URN) in a population-based sample of African American adults.

Design, Setting, and Participants

This cross-sectional study, conducted from April 2014 to April 2018, included a population-based sample of self-identified African American participants 40 years and older from 30 contiguous census tracts in Inglewood, California. Participants underwent a complete ophthalmic examination and an in-home-administered questionnaire to assess sociodemographic, lifestyle, biological, medical, and health care and eye care usage RFs associated with UCRE and URN. Measurements of visual acuity (VA) were performed using a standard Early Treatment Diabetic Retinopathy Study protocol. Noncycloplegic automated refraction with supplemental subjective refraction was performed. UCRE was defined as an improvement of 2 or more lines with refraction in the better-seeing eye. URN was defined as an improvement of 2 or more lines with refraction in the better-seeing eye in those persons who were visually impaired. Sex- and age-specific burden of UCRE and URN were calculated, and multiple regression analyses were used to identify independent RFs. Study data were analyzed from May 2018 to December 2023.

Exposures

Presence or absence of correctable refractive error.

Main Outcomes and Measures

Self-reported sex- and age-specific prevalence of and risk indicators of UCRE and URN.

Results

Of the 7957 eligible participants in the African American Eye Disease Study (AFEDS), 6347 (80%) completed both the in-home interview and the clinical examination. Of these, 6337 participants (mean [SD] age, 61 [11] years; 3997 female [63%]) with complete refractive error data were included in the analysis. Refractive error-related correctable visual impairment was present in over two-thirds of participants with visual impairment (68.7%). The overall prevalence of any UCRE was 14.6% (925 of 6337), and the overall prevalence of any URN was 5.4% (URN1 [those with presenting VA of worse than 20/40 in the better-seeing eye but who could achieve 20/40 or better with correction], 157 of 2893; URN2 [those with presenting VA of worse than 20/40 in the better-seeing eye but who could achieve an improvement of 2 or more lines with refractive correction], 155 of 2891).

Conclusions and Relevance

Results of this cross-sectional study suggest a high burden of refractive error-associated correctable refractive error in African American adults, making it the leading cause of visual impairment in this population. Providing universal coverage for vision care and prescription glasses is an affordable and achievable health care intervention that could reduce the burden of visual impairment in African American adults by over two-thirds and likely raise the quality of life and work productivity, especially in this vulnerable minority population.

Needs and views on eye health and women's empowerment and theory of change map: implication on the development of a women-targeted eyecare programme for older Zanzibari craftswomen

OBJECTIVES

To assess needs and views regarding eye health and empowerment from craftswomen's perspectives to develop a theory of change (ToC) for a women-targeted eyecare programme.

MATERIAL AND METHODS

Eighteen stakeholders participated in a 2-day consultation workshop in Zanzibar. The composition was (1) 15 women and 3 men; (2) Unguja (n=8), Pemba (n=6) and Tanzania mainland (n=4) and (3) craftswomen (n=14) and governmental stakeholders (n=4). Thematic analysis determined the craftswomen's needs and views regarding eye health and empowerment and subsequently inputs, activities, outputs, outcomes and impact to develop the programme's initial ToC. In refining the initial ToC, we used insights from a qualitative study suggesting that improved near vision is perceived by craftswomen as a potential source of empowerment across economic, psychological, social, political and educational dimensions.

RESULTS

The eye conditions experienced by the craftswomen were eye irritation caused by foreign bodies, the need for near spectacles and other eye morbidities. They were advised by the cooperatives to visit eye health centres for treatment. The main barriers to accessing services were inaccessibility and unaffordability of eye services and a lack of eye health knowledge and practices. Nineteen subthemes on women empowerment (economic n=4, social n=4, psychological n=6, education n=2 and political n=3) were obtained. We created a ToC on how investing in improving craftswomen near vision could achieve empowerment.

CONCLUSION

The participants provided insights into their needs and how they would like the eyecare programme to be implemented and how they see they could be empowered in the process.

Global, Regional, and National Epidemiology of Visual Impairment in Working-Age Individuals, 1990-2019

Importance

Visual impairment in working-age individuals can affect their general health and employment prospects, leading to decreased social and economic productivity and increased poverty rates. Nonetheless, investigations in this population appear to be limited.

Objective

To investigate the trends of visual impairment prevalence and disability-adjusted life-years (DALYs) in working-age individuals from 1990 to 2019.

Design, Setting, and Participants

This cross-sectional, population-based study used data for individuals of working age (15-64 years) from 204 countries and territories obtained from the Global Burden of Disease 2019 study. The data analysis was performed between May 1 and 10, 2023.

Exposure

Visual impairment, defined as visual acuity of less than 6/18 (20/60) or near visual acuity of less than 6/12 (20/40) distance equivalent as determined by Snellen chart.

Main Outcomes and Measures

Trends of visual impairment prevalence, DALYs, and corresponding estimated annual percent changes (EAPCs) from 1990 to 2019 were stratified according to region, nation, and sociodemographic index (SDI).

Results

There were 437 539 484 (95% uncertainty interval [UI], 325 463 851-575 573 588) prevalent cases of visual impairment globally (53.12% female and 46.88% male) in 2019, representing an increase of 91.46% from 1990 (prevalent cases, 228 530 964; 95% UI, 172 515 833-297 118 596). Over 3 decades, visual impairment-associated DALYs increased from 7 601 852 (95% UI, 5 047 030-11 107 897) to 12 563 276 (95% UI, 8 278 866-18 961 723). Among the 5 SDI groups, the low-SDI group had the largest increase in DALYs (898 167 [95% UI, 597 161-1 301 931] in 1990 to 1 634 122 [95% UI, 1 079 102-2 444 381] in 2019). Regionally, the greatest increase in prevalence was observed in Eastern Europe (EAPC, 0.10; 95% CI, 0.02-0.19). Among all countries and territories, Nepal had the highest national prevalence of visual impairment per 100 000 population in 2019 (26 008.45; 95% UI, 19 987.35-32 482.09), while South Sudan had the highest DALY rate per 100 000 population (480.59; 95% UI, 316.06-697.06).

Conclusions and Relevance

Despite the mild decrease in visual impairment prevalence rates in less-developed countries, these findings suggest that the number of prevalent cases globally has increased substantially, with discernible unfavorable patterns in developed regions. The findings support the notion that visual impairment in working-age individuals is a growing global health challenge. A better understanding of its epidemiology may facilitate the development of appropriate measures for prevention and treatment from both medical and social perspectives.

Factors influencing the need and willingness for presbyopic correction: a cross sectional study from south India

Presbyopia is an age-related physiological phenomenon in which eye gradually losses its ability to accommodate. It is one of the leading causes of visual impairment worldwide, especially in adults above the age of 40. If uncorrected, it can significantly impair a patient's quality of life. This study aims to evaluate the factors which affects patient's need and willingness to accept presbyopic correction. This cross-sectional analytical study was carried out in a semi urban tertiary care hospital from Jan 2021 to June 2022 among patients aged 40 and above who presented to Outpatient department (OPD). Demographic details, medical history, presenting ocular complaints pertaining to presbyopia, spectacle use and decision regarding using near vision correction were noted. Ocular examination included refraction and ocular biometry. Factors that may have influenced complaints of presbyopia or willingness to accept presbyopic correction were analysed. Three hundred and forty two patients with a mean age of 48.55 ± 6.68 years were included. Of these, 262 (76.61%) patients presented with chief complaints related to presbyopia. Those with higher educational qualification (p = 0.031), hypermetropia (p = 0.021), shallower AC depth (p = 0.028) and on medications for systemic ailments (p = 0.01), were more likely to present with chief complaints attributable to presbyopia. Among them, those with higher educational qualifications (p = 0.02) and skilled workers were more likely to accept near vision glasses (p = 0.02), while those with lower Hb (p = 0.01) and myopia (p = 0.01) were less likely to accept correction for presbyopia. Among the 80 patients without chief complaints related to presbyopia, 35 (43.75%) were not willing to accept near vision glasses. Those with higher BMI (p = 0.04) and hypermetropes (p = 0.05) were more willing to accept presbyopic correction. Presbyopia constitutes a significant reason for patients above the age of 40 visiting eye care facility. Multiple socio-economic, systemic and ocular factors influenced both the chief complaints related to presbyopia and willingness to accept presbyopic correction.

Development and Validation of the Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire

PURPOSE

To develop and validate a novel patient-reported outcome (PRO) measure to assess vision-related functioning in individuals with severe peripheral field loss (PFL).

DESIGN

Prospective outcome measure development/validation study.

METHODS

A 127-item questionnaire was developed based on a prior qualitative interview study. A total of 116 participants with severe PFL due to retinitis pigmentosa (RP) or glaucoma were recruited at the Kellogg Eye Center and completed the Likert-scaled telephone-administered questionnaire. Included participants had a horizontal extent of their visual field <20 degrees (RP) or a mixed or generalized stage 4 to 5 defect using the Enhanced Glaucoma Staging System (glaucoma) in the better seeing eye (or in 1 eye if the fellow eye visual acuity was <20/200). Response data were analyzed using exploratory factor analysis and Rasch modeling. Poorly functioning items were eliminated, confirmatory factor analysis was used to ensure scale unidimensionality, and the model was refit to produce the final instrument.

RESULTS

The final Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire contains 53 items across 6 domains: mobility, object localization, object recognition, reading, social functioning, and technology. There were 74 items removed because of high missingness, poor factor loadings, low internal consistency, high local dependency, low item information, item redundancy, or differential item functioning. Using Rasch item calibrations, person ability scores could be calculated for each of the 6 unidimensional LV-SCOPE domains with good test-retest stability.

CONCLUSIONS

The LV-SCOPE Questionnaire provides a valid and reliable measure of vision-related functioning across 6 key domains relevant to individuals with severe PFL. Findings support the clinical utility of this psychometrically valid instrument.

Modelling ready-made spectacle coverage for children and adults using a large global database

BACKGROUND/AIMS

To model the suitability of conventional ready-made spectacles (RMS) and interchangeable-lens ready-made spectacles (IRMS) with reference to prescribing guidelines among children and adults using a large, global database and to introduce a web-based application for exploring the database with user-defined eligibility criteria.

METHODS

Using refractive power and interpupillary distance data for near and distance spectacles prescribed to children and adults during OneSight clinics in 27 countries, from 2 January 2016 to 19 November 2019, we modelled the expected suitability of RMS and IRMS spectacle designs, compared with custom-made spectacles, according to published prescribing guidelines.

RESULTS

Records of 18 782 presbyopic adult prescriptions, 70 619 distance adult prescriptions and 40 862 paediatric prescriptions were included. Globally, 58.7%-63.9% of adults could be corrected at distance with RMS, depending on the prescribing cut-off. For presbyopic adult prescriptions, coverage was 44.1%-60.9%. Among children, 51.8% were eligible for conventional RMS. Coverage for all groups was similar to the above for IRMS. The most common reason for ineligibility for RMS in all service groups was astigmatism, responsible for 27.2% of all ineligible adult distance prescriptions using the strictest cut-off, 31.4% of children's prescriptions and 28.0% of all adults near prescriptions globally.

CONCLUSION

Despite their advantages in cost and convenience, coverage delivered by RMS is limited under current prescribing guidelines, particularly for children and presbyopic adults. Interchangeable designs do little to remediate this, despite extending coverage for anisometropia. Our free application allows users to estimate RMS coverage in specific target populations.

Subjective Wellbeing, Work Performance and Lived Experience of Zanzibari Women Entrepreneurs with Uncorrected Functional Presbyopia: A Pre-Post Mixed-Methods Study

PURPOSE

Uncorrected presbyopia has been shown to reduce Zanzibari women's quality of life. In this mixed-methods study, we examined the subjective wellbeing and self-reported work performance among older women entrepreneurs with functional presbyopia before and shortly after correction, and how poor vision at close distance affected their daily lives.

METHODS

Women entrepreneurs underwent eye examination to identify those with uncorrected functional presbyopia. Their subjective wellbeing and work performance were both measured in Cantril's ladder. Ready-made glasses were then provided and 30 minutes to an hour later, their subjective wellbeing and work performance was remeasured. Twenty women entrepreneurs were interviewed to understand their lived experience with uncorrected presbyopia.

RESULTS

Two-hundred-seventeen women entrepreneurs were included in the survey (mean age 51.6 years, SD 8.64). Women entrepreneurs had a mean subjective wellbeing score of 3.32 (SD 1.10) pre-correction and 5.99 (SD 1.13) post-correction (p < .001), and a mean self-rated current work performance score of 4.62 (SD 1.36) before correction and 5.47 (SD 1.35) post-correction (p < .001). One-hundred-and-ninety (87.6%) and 121 women entrepreneurs (55.8%) rated their current subjective wellbeing and work performance scores < 5, respectively. Around 1/4 of women entrepreneurs reported having severe difficulties with near tasks.

CONCLUSION

Poor vision at a close distance caused by uncorrected functional presbyopia negatively affected economic, physical and psychosocial aspects of women entrepreneurs' lives. Subjective wellbeing and self-reported work productivity scores improved significantly shortly after presbyopia was corrected. More research with longer follow-up is needed to understand the full benefits of correcting presbyopia.

IRIS® Registry (Intelligent Research In Sight) Analysis of the Incidence of Monovision in Cataract Patients with Bilateral Monofocal Intraocular Lens Implantation

Purpose

To determine the incidence of pseudophakic monovision among patients bilaterally implanted with monofocal intraocular lenses (IOLs) and to characterize the distribution of myopic offsets achieved.

Patients and Methods

This retrospective database study included data on patients receiving care from ophthalmologists who contributed to the Academy IRIS® (Intelligent Research In Sight) Registry. Anonymized data were collected, including patient age, ethnicity, procedure data (CPT code, date, laterality), and postoperative manifest refractive spherical equivalent (MRSE) in both eyes implanted with monofocal or monofocal toric IOLs. No data regarding IOL manufacturer, model, or power were collected. One primary outcome measure was the percentage of patients achieving monovision (defined as emmetropia within ±0.25 diopters [D] in one eye and a myopic offset of ≥0.50 D in the fellow eye) among all patients receiving bilateral monofocal IOLs at the time of cataract surgery between January 1, 2016, and September 1, 2019, with at least 90 days of follow-up. Other primary outcomes included the distribution and frequency of myopic offsets (anisometropia) between eyes.

Results

Of the 16,765 people receiving bilateral monofocal IOLs within the study period, 4796 (28.6%) achieved emmetropia in at least one eye, as defined by an MRSE within ± 0.25 D. The incidence of monovision among these patients was 34.2% (1638/4796). One-quarter (24.7%; 405/1638) of patients who achieved monovision had a myopic offset between 0.50 and 0.74 D, with more than one-third (35.2%; 576/1638) falling within 0.75-1.24 D and 18.0% within 1.25-1.74 D. A myopic offset ≥1.75 D was observed in 22.1% (362/1638) of patients who achieved monovision.

Conclusion

Pseudophakic monovision for presbyopia correction was achieved in ~34% of patients in the IRIS Registry bilaterally implanted with monofocal IOLs, with myopic offsets typically ranging from 0.5 to 1.24 D.

Understanding Presbyopia in Asmara: Prevalence, Association with Refractive Error, and Age-Based Addition

Background

Presbyopia is an age-related progressive decrease of near vision, corrected by near addition glasses. These age-appropriate glasses, however, vary across different geographical locations and populations. But there is no existing information on the age-based addition for Asmara and high number of uncorrected presbyopes, so this study determined the required age-based addition for the presbyopes in Asmara.

Methods

A cross-sectional study was conducted on patients aged 35-60 years who visited all eye centers in the city. Patients with best-corrected visual acuity in both eyes better than 6/9 were included in the study. Near add was calculated using Monocular Estimation Method (MEM) and amplitude of accommodation results. Data entry and analysis were performed using Statistical Package for the Social Sciences v. 20.

Results

This study included 1310 participants of whom 48.5% were females and 51.5% were males. The prevalence of presbyopia was found to be 74.1% out of which 44% were females. There were 35.6% of the participants with a previous prescription for glasses, though only 24% of the participants presented with glasses on. Among the different occupational categories, laborers were the ones who had the highest number of presbyopes (79.5%), office workers (73%), and housewives (68.7%). The mean age of those with presbyopes was 49.5 ± 5.8 years. Multivariable analysis performed for presbyopia showed that older age and female sex were associated with a higher likelihood of presbyopia (<0.005). An addition table was prepared separately for males and females. On post-hoc tests, no significant association was found between the given and the different refractive status.

Conclusion

The study showed that there is a high level of uncorrected presbyopes in the city, so the availability of refraction sites and glasses accessibility needs to increase. The near addition demand for this population varies from the previously stated amount in other countries. Therefore, guidelines specifically prepared for a society are necessary.

Incidence, causes and risk factors of vision loss in rural Southern China: 6-year follow-up of the Yangxi Eye Study

PURPOSE

To report the 6-year incidence, causes and risk factors for vision loss (visual impairment (VI) and blindness), among elderly adults in rural southern China.

METHODS

Population-based, cohort study. Initiated in 2014, the study recruited participants aged 50 and older using random cluster sampling from Yangxi County. All eligible participants were invited to attend interviews and comprehensive eye examinations at the 6-year follow-up between November 2020 and March 2021. The WHO categories of vision loss were used to define incident cases of VI (3/60≤VA <6/12), moderate-to-severe VI (MSVI) (3/60≤VA<6/18) and blindness (VA <3/60) in the better-seeing eye.

RESULTS

Among the 5825 baseline participants, 3187 (64.4%) of 4946 surviving subjects participated in the 6-year follow-up. Based on presenting and best-corrected VA, respectively, the crude incidence rate of blindness was 0.8% (95% CI 0.5% to 1.1%) vs 0.3% (95% CI 0.1% to 0.5%), for MSVI 6.7% (95% CI 5.7% to 7.6%) vs 4.6% (95% CI 3.8% to 5.4%) and for any VI 16.1% (95% CI 14.5% to 17.6%) vs 12.9% (95% CI 11.6% to 14.1%). Cataract (48.3%) and refractive errors (44.4%) were the most common causes of vision loss. Factors significantly associated with greater incident vision loss were older age, female sex, less education, living alone and longer axial length (all p<0.05).

CONCLUSIONS

Substantial work is still required to reduce avoidable vision loss in rural China. Screening outreach and efforts to improve awareness which target the poorer and less educated are urgently needed to reduce the growing unmet need for eye care due to ageing.

How does a pair of near-vision spectacle correction empower older Zanzibari craftswomen?: A qualitative study on perception

BACKGROUND

Studies have shown that correcting presbyopia among women could increase short-term income and quality of life. However, it is unclear whether these short-term outcomes translate to long-term empowerment. This is partly due to women's empowerment being under-studied in the eye health field. Hence, we attempted to understand Zanzibari craftswomen's perception of how near-vision spectacle correction could empower them.

METHODS

Semi-structured interviews were conducted with 24 craftswomen with presbyopia (7 to 21 April 2022), identified from Zanzibari cooperatives using quota and heterogeneity sampling. We included a sample of tailors, beaders/weavers, and potters who were 40 years and older. Directed content analysis was performed on interview transcripts.

RESULTS

Two themes and seven sub-themes emerged from the data. Craftswomen perceived that at the personal level, near-vision spectacle correction could improve their economic empowerment (better income and savings and buying things for themselves), psychological empowerment (more self-confidence and decision-making), political empowerment (taking up leadership roles), and educational empowerment (acquiring new skills). At a relational level, they perceived that near-vision spectacle correction could bring about economic empowerment (ability to buy things for the family), social empowerment (ability to participate in social activities), and educational empowerment (ability to educate other women).

CONCLUSION

Older craftswomen perceived that correcting near vision could empower them at personal and relational levels that encompass economic, psychological, social, political and educational empowerment. The findings laid the foundation for future research into eye health and women's empowerment.

Refractive error, eye care needs and attitude towards spectacle wearing among older Zanzibari craftswomen and implications for developing women-targeted services: a cross-sectional study

BACKGROUND

Aged Zanzibari women are in a disadvantaged position, having high demand for near-vision spectacles. Currently, there is no information on the eye health status of craftswomen, which makes planning a women-targeted project to deliver eye health services to older craftswomen in Zanzibar difficult. We assessed the prevalence of vision impairment, refractive error, presbyopia, effective spectacle coverage (distance and near) and attitude towards spectacle wearing among older Zanzibari craftswomen.

METHODS AND ANALYSIS

This was a cross-sectional study. Unaided and presenting distance and near vision of craftswomen 35 years and older were assessed at the women's co-operatives. We determined the number of those with distance vision poorer than 6/12 and their causes (distance-vision impairment), the number of those with near vision poorer than N8 at 40 cm (presbyopia) and the number of those whose distance and/or near-vision needs were met adequately with their habitual spectacles (effective distance and near spectacle coverages). A piloted and validated questionnaire (15 statements) was used to determine their attitude towards spectacle wearing.

RESULTS

In all, 263 craftswomen participated in the survey (mean age 52.1 years±9.4 years). The prevalence of distance vision impairment among the craftswomen was 29.7% (95% CI 24.2% to 35.6%), the primary cause being uncorrected refractive error (n=51, 65.4%), and none were corrected. The prevalence of presbyopia was 86.6% (95% CI 81.5% to 90.7%, n=231) and the effective near spectacle coverage was 0.99%. The craftswomen showed a positive attitude towards spectacle wearing (strongly agree or agree) based on 12 out of 15 statements.

CONCLUSION

The high burden of vision impairment, uncorrected distance refractive error and presbyopia, and a positive attitude towards spectacle wearing among older craftswomen in Zanzibar indicated the need for women-targeted eye health programmes in low-resource settings.

Burden of near vision loss in China: findings from the Global Burden of Disease Study 2019

PURPOSE

To investigate the burden of near vision loss (NVL) in China by year, age and gender from 1990 to 2019.

METHODS

We used estimates from the Global Burden of Disease (GBD) 2019 study to report the prevalence and disability-adjusted life-years (DALYs) due to NVL in China. Estimates of crude counts and age-standardised rates per 100 000 population are accompanied by 95% uncertainty intervals (UIs). We summarised the age-specific and sex-specific patterns and trends regarding the burden of NVL in China, compared with seven neighbouring countries.

RESULTS

From 1990 to 2019, the all-age number and rate for NVL prevalence and DALYs increased significantly in China (all p<0.001). The age-standardised rate decreased from 7538.1 (95% UI 6946.3 to 8075.1) to 7392.9 (95% UI 6855.8 to 7890.5) per 100 000 population for NVL prevalence (p=0.107), and from 74.9 (95% UI 69.6 to 79.9) to 73.8 (95% UI 70.6 to 80.1) per 100 000 population for DALYs (p=0.388). Women had higher NVL prevalence (t=170.1, p<0.001) and DALYs (t=192.5, p<0.001) than men. Higher disease burden of NVL was observed in the middle-aged and elderly population. The age-standardised prevalence and DALY rate attributable to NVL in China were lower than in India, North Korea, Pakistan (all p<0.001), but higher than Russia, South Korea, Singapore and Japan (all p<0.001).

CONCLUSIONS

Despite a small decrease in age-standardised prevalence and DALYs due to NVL in China in the past two decades, the existing burden is still considerable and significantly higher compared with neighbouring developed countries. An approach that includes all stakeholders is needed to further reduce this burden.

Prevalence of refractive error in Portugal estimated from ophthalmic lens manufacturing data: Ten-years analysis

PURPOSE

To investigate the prevalence, distribution and trends of refractive error from ophthalmic lens manufacturing data over a ten-year period.

METHODS

Fully anonymized data from ophthalmic lenses, for the years between 2010 and 2020, provided by the leading ophthalmic lens manufacturer operating in Portugal were analysed (no human participants were involved in the research). Prescriptions delivered were divided in single vision prescriptions and progressive/multifocal prescriptions and categorized into 14 spherical equivalent ranges. Given the lack of absolute values, indirect estimates and a qualitative analysis of the current situation and trends on refractive error epidemiology was carried out.

RESULTS

Dataset from manufacturer comprises percentage values of ophthalmic lenses dispensed in Portugal. The distribution of ophthalmic prescriptions for single vision prescriptions presents most of the observations in the range [-1.49, -0.50] diopters, in every year from 2010 to 2020. For the progressive prescription's lenses, most of the observations is in an interval of two ranges, [0.50, 1.49] and [1.50, 2.99] diopters. From 2010 to 2020 the proportion of single vision ophthalmic lens prescriptions for myopia increased from 38.13% to 46.21%; the proportion for high myopia increased from 2.76% to 4.45%; and the proportion for hyperopia decreased from 40.85% to 31.36%.

CONCLUSIONS

Ophthalmic lens manufacturing data can be a valuable source for long-term analysis of refractive error prescription and trends over time. It was possible to observe a trend of increasing prevalence of myopia and high myopia from 40.89% in 2010 to 50.66% in 2020. That increase trend has important implications for public health and in the planning of services.

New insights in presbyopia: impact of correction strategies

Presbyopia occurs when the physiologically normal age-related reduction in the eyes focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual’s requirements. Hence, it is more about the impact it has on an individual’s visual ability to function in their environment to maintain their lifestyle than a measured loss of focusing ability. Presbyopia has a significant impact on an individual’s quality of life and emotional state. While a range of amelioration strategies exist, they are often difficult to access in the developing world and prescribing is generally not optimal even in developed countries. This review identified the need for a standardised definition of presbyopia to be adopted. An appropriate battery of tests should be applied in evaluating presbyopic management options and the results of clinical trials should be published (even if unsuccessful) to accelerate the provision of better outcomes for presbyopes.

Development and Validation of a Digital (Peek) Near Visual Acuity Test for Clinical Practice, Community-Based Survey, and Research

Purpose

Unaddressed near vision impairment (NVI) affects more than 500 million people. Testing near vision is necessary to identify those in need of services. To make such testing readily accessible, we have developed and validated a new smartphone-based near visual acuity (NVA) test: Peek Near Vision (PeekNV).

Methods

Two forms of the PeekNV test were developed: (1) quantitative measurement of NVA, and (2) binary screening test for presence or absence of NVI. The validity study was carried out with 483 participants in Sagarmatha Choudhary Eye Hospital, Lahan, Nepal, using a conventional Tumbling "E" Near Point Vision Chart as the reference standard. Bland-Altman limits of agreement (LoA) were used to evaluate test agreement and test-retest repeatability. NVI screening was assessed using Cohen's kappa coefficient, sensitivity, and specificity.

Results

The mean difference between PeekNV and chart NVA results was 0.008 logMAR units (95% confidence interval [CI], -0.005 to 0.021) in right eye data, and the 95% LoA between PeekNV and chart testing were within 0.235 and -0.218 logMAR. As a NVI screening tool, the overall agreement between tests was 92.9% (κ = 0.85). The positive predictive value of PeekNV was 93.2% (95% CI, 89.6% to 96.9%), and the negative predictive value 92.7% (95% CI, 88.9% to 96.4%). PeekNV had a faster NVI screening time (11.6 seconds; 95% CI, 10.5 to 12.6) than the chart (14.9 seconds; 95% CI, 13.5 to 16.2; P < 0.001).

Conclusions

The PeekNV smartphone-based test produces rapid NVA test results, comparable to those of an accepted NV test.

Translational Relevance

PeekNV is a validated, reliable option for NV testing for use with smartphones or digital devices.

Validation of a novel iPhone application for evaluating near functional visual acuity

Monitoring dynamic changes in near vision is important for early detection of presbyopia. This study assessed the accuracy and reliability of a new smartphone-based application, the Smart Vision Check (SVC), compared with those of a conventional device (AS-28; Kowa, Aichi, Japan), for measuring near functional visual acuity (NFVA). We enrolled 115 healthy volunteers aged ≥ 20 years with bilateral best-corrected visual acuity of ≥ 20/25. The SVC was designed for use on an Apple iPhone SE2 to measure NFVA by tapping on the orientation icon manually. Conventional FVA was measured using the AS-28 with - 2.50 D added to the best distance correction at baseline. There was no significant difference in NFVA-related measurements between the AS-28 and SVC (P > 0.05). The Spearman correlation coefficients of NFVA measurements between the two devices were over 0.60 (P < 0.001). The Bland-Altman plot indicated minimal bias with limits of agreements of ± 0.34 logMAR for NFVA with habitual correction when comparing the AS-28 and SVC. The intraclass correlation coefficient of the repeated SVC-measured NFVA was 0.915 (95% CI 0.800-0.969). In summary, the SVC has the potential to evaluate NFVA in a relatively easy manner. Applied clinically, the SVC can be useful for presbyopia screening.

Effective refractive error coverage in adults aged 50 years and older: estimates from population-based surveys in 61 countries

BACKGROUND

In 2021, WHO Member States endorsed a global target of a 40-percentage-point increase in effective refractive error coverage (eREC; with a 6/12 visual acuity threshold) by 2030. This study models global and regional estimates of eREC as a baseline for the WHO initiative.

METHODS

The Vision Loss Expert Group analysed data from 565 448 participants of 169 population-based eye surveys conducted since 2000 to calculate eREC (met need/[met need + undermet need + unmet need]). A binary logistic regression model was used to estimate eREC by Global Burden of Disease (GBD) Study super region among adults aged 50 years and older.

FINDINGS

In 2021, distance eREC was 79·1% (95% CI 72·4-85·0) in the high-income super region; 62·1% (54·7-68·8) in north Africa and Middle East; 49·5% (45·0-54·0) in central Europe, eastern Europe, and central Asia; 40·0% (31·7-48·2) in southeast Asia, east Asia, and Oceania; 34·5% (29·4-40·0) in Latin America and the Caribbean; 9·0% (6·5-12·0) in south Asia; and 5·7% (3·1-9·0) in sub-Saharan Africa. eREC was higher in men and reduced with increasing age. Global distance eREC increased from 2000 to 2021 by 19·0%. Global near vision eREC for 2021 was 20·5% (95% CI 17·8-24·4).

INTERPRETATION

Over the past 20 years, distance eREC has increased in each super region yet the WHO target will require substantial improvements in quantity and quality of refractive services in particular for near vision impairment.

FUNDING

WHO, Sightsavers, The Fred Hollows Foundation, Fondation Thea, Brien Holden Vision Institute, Lions Clubs International Foundation.

Global, regional, and national years lived with disability due to blindness and vision loss from 1990 to 2019: Findings from the Global Burden of Disease Study 2019

Purpose

This study aimed to provide a comprehensive assessment of burden estimates and the secular trend of blindness and vision loss, as measured by years lived with disability (YLDs), at the global, regional, and national levels.

Methods

The age-standardized YLD rates (ASYRs) due to blindness and vision loss and its subtypes, including moderate vision loss, severe vision loss, blindness, and presbyopia, from 1990 to 2019 were extracted from the Global Burden of Disease Study 2019 database. The estimated annual percentage changes (EAPCs) were calculated to quantify the temporal trends in the ASYRs due to blindness and vision loss.

Results

In 2019, the global ASYRs per 100,000 population was 327.98 for blindness and vision loss, specifically, 85.81 for moderate vision loss, 74.86 for severe vision loss, 95.03 for blindness, and 62.27 for presbyopia. From 1990 to 2019, the ASYRs due to blindness and vision loss slightly decreased. Females showed higher ASYRs than males in 2019. The global highest ASYRs were observed in South Asia and sub-Saharan Africa. Negative associations were found between the burden estimates of blindness and vision loss and the sociodemographic index levels. The EAPCs of ASYRs in blindness and vision loss were significantly negatively correlated with the ASYRs in 1990 and positively correlated with human development indices in 2019.

Conclusions

Globally, blindness and vision loss continue to cause great losses of healthy life. Reasonable resource allocation and health-service planning are needed for the prevention and early intervention of disabilities caused by vision loss.

Potential productivity loss from uncorrected and under-corrected presbyopia in low- and middle-income countries: A life table modeling study

Objective

To estimate the burden of potential productivity losses due to uncorrected and under-corrected presbyopia in LMICs among the working-age population in both the cross-sectional and longitudinal manner.

Methods

We extracted data for the prevalence of presbyopia from the Global Burden of Diseases (GBD), Injuries, and Risk Factors Study 2019. Data for the gross domestic product (GDP) per capita were extracted from the World Bank database and Central Intelligence Agency's World Factbook. We introduced life table models to construct age cohorts (in 5-year age groups) of the working-age population (aged from 40 to 64 years old) in LMICs, with simulated follow-up until 65 years old in people with and without uncorrected presbyopia. The differences in productivity-adjusted life years (PALYs) lived and productivity between these two cohorts were calculated. The potential productivity loss was estimated based on GDP per capita. The WHO standard 3% annual discount rate was applied to all years of life and PALYs lived.

Results

In 2019, there were 238.40 million (95% confidence interval [CI]: 150.92-346.78 million) uncorrected and under-corrected presbyopia cases in LMICs, resulting in 54.13 billion (current US dollars) (95% confidence interval [CI]: 34.34-79.02 billion) potential productivity losses. With simulated follow-up until retirement, those with uncorrected and under-corrected presbyopia were predicted to experience an additional loss of 155 million PALYs (an average loss of 0.7 PALYs per case), which was equivalent to a total loss of US$ 315 billion (an average loss of US$ 1453.72 per person).

Conclusions

Our findings highlight the considerable productivity losses due to uncorrected and under-corrected presbyopia in LMICs, especially in a longitudinal manner. There is a great need for the development of enabling eye care policies and programs to create access to eye care services, and more healthcare investment in the correction of presbyopia in the working-age population in LMICs. This study could provide evidences for some potential health-related strategies for socio-economic development.

The economic and social costs of visual impairment and blindness in India

Purpose

To provide a current estimate of the economic and social costs (or welfare costs) of visual impairment and blindness in India.

Methods

Using evidence from the recently conducted Blindness and Visual Impairment Survey across India, the Lancet Global Health Commission on Global Eye Health and other sources, we developed an economic model that estimates the costs of reduced employment, elevated mortality risk, education loss for children, productivity loss in employment, welfare loss for the unemployed, and caregiver costs associated with moderate and severe visual impairment (MSVI) and blindness. Probabilistic sensitivity analyses were also conducted by varying key parameters simultaneously.

Results

The costs of MSVI and blindness in India in 2019 are estimated at INR 1,158 billion (range: INR 947-1,427 billion) or $54.4 billion at purchasing power parity exchange rates (range: $44.5-67.0 billion), accounting for all six cost streams. The largest cost was for the loss of employment, whereas the the second largest cost was for caregiver time. A more conservative estimate focusing only on employment loss and elevated mortality risk yielded a cost of INR 504 billion (range: INR 348-621 billion) or $23.7 billion (range: $16.3-29.2 billion).

Conclusion

Poor eye health imposes a non-trivial recurring cost to the Indian economy equivalent to 0.47% to 0.70% of GDP in the primary scenario, a substantial constraint on the country's growth aspirations. Furthermore, the absolute costs of poor eye health will increase over time as India ages and becomes wealthier unless further progress is made in reducing the prevalence of MSVI and blindness.

The effect of poor vision on economic farm performance: Evidence from rural Cambodia

Roughly one-fifth of the global population is affected by poor visual acuity. Despite the fact that inhabitants of rural areas in low-income countries are most distressed by this, no prior research has studied the impact of poor visual acuity on the economic performance of farms. We conduct a standardized eye test with 288 farm managers in rural Cambodia and find that around 30 percent of our sample suffers from poor visual acuity in terms of nearsightedness (myopia). Our analyses indicate a statistically significant and economically meaningful association of poor visual acuity with economic farm performance. Our results show that gross margins for cropping activities per year could be, on average, around 630 USD higher if farm managers were able to correct for poor vision. Our results suggest that poor visual acuity impairs farm managers from tapping the full potential of their business, which in turn decreases their chance to break the vicious cycle of poverty.

A pilot cost-benefit analysis of a children’s spectacle reimbursement scheme: Evidence for Including children’s spectacles in Mongolia’s Social Health Insurance

Background and aim

Globally, 12.8 million children have vision impairment due to uncorrected refractive error (URE). In Mongolia, one in five children needs but do not have access to spectacles. This pilot cost-benefit analysis aims to estimate the net benefits of a children’s spectacles reimbursement scheme in Mongolia.

Methods

A willingness-to-pay (WTP) survey using the contingent valuation method was administered to rural and urban Mongolia respondents. The survey assessed WTP in additional annual taxes for any child with refractive error to be provided government-subsidised spectacles. Net benefits were then calculated based on mean WTP (i.e. benefit) and cost of spectacles.

Results

The survey recruited 50 respondents (mean age 40.2 ± 9.86 years; 78.0% women; 100% response rate) from rural and urban Mongolia. Mean WTP was US$24.00 ± 5.15 (95% CI US$22.55 to 25.35). The average cost of a pair of spectacles in Mongolia is US$15.00. Subtracting the average cost of spectacles from mean WTP yielded a mean positive net benefit of US$9.00.

Conclusion

A spectacle reimbursement scheme is potentially a cost-effective intervention to address childhood vision impairment due to URE in Mongolia. These preliminary findings support the proposal of the inclusion of children’s spectacles into existing Social Health Insurance. A much larger random sample could be employed in future research to increase the precision and generalisability of findings.

All eyes on the price: An assessment of the willingness-to-pay for eyeglasses in rural Burkina Faso

Vision impairment is the most common disability worldwide and it is untreated in large parts of the developing world. We assess the willingness-to-pay (WTP) for eyeglasses among adults in a resource-poor rural setting. We elicit the WTP using the Becker-DeGroot-Marschak (BDM) method. We combine this approach with a layaway scheme and a video intervention to probe to what extent liquidity constraints and information influence the WTP. Our results show that the average WTP is close to the cost of production for corrective glasses. Nevertheless, we find evidence for information constraints. Our video intervention raises the WTP for corrective glasses by 16 percent. We do not find evidence of screening effects, that is after 6 months, use is unrelated to the initial WTP.

Pilocarpine 1.25% and the changing landscape of presbyopia treatment

PURPOSE OF REVIEW

Despite affecting approximately 1.8 billion individuals worldwide, until recently, a pharmacologic treatment for presbyopia was not available. This special commentary reviews the treatment of presbyopia with a focus on the recently approved medication Vuity (pilocarpine 1.25%, Allergan, an AbbVie Company).

RECENT FINDINGS

Vuity is a re-engineered formulation of pilocarpine 1.25% specifically designed for the treatment of presbyopia. Recently published results from the GEMINI 1 Phase 3 clinical trial reported improvement in distance corrected near vision without significant compromise in distance vision. No unexpected safety findings were reported with mild headache being the most common adverse event. Notably, there were no reported cases of retinal detachment or angle closure during the 30-day phase 3 clinical trials.

SUMMARY

Vuity is the first treatment designed and FDA approved to treat the growing presbyopia market. Phase 3 clinical trials demonstrated its ability to improve near vision without significant compromise in distance vision. We recognize this paradigm shift in the treatment of presbyopia and anxiously await additional treatment options for this ubiquitous condition.

Prediction of manifest refraction using machine learning ensemble models on wavefront aberrometry data

PURPOSE

To assess the performance of machine learning (ML) ensemble models for predicting patient subjective refraction (SR) using demographic factors, wavefront aberrometry data, and measurement quality related metrics taken with a low-cost portable autorefractor.

METHODS

Four ensemble models were evaluated for predicting individual power vectors (M, J₀, and J₄₅) corresponding to the eyeglass prescription of each patient. Those models were random forest regressor (RF), gradient boosting regressor (GB), extreme gradient boosting regressor (XGB), and a custom assembly model (ASB) that averages the first three models. Algorithms were trained on a dataset of 1244 samples and the predictive power was evaluated with 518 unseen samples. Variables used for the prediction were age, gender, Zernike coefficients up to 5th order, and pupil related metrics provided by the autorefractor. Agreement with SR was measured using Bland-Altman analysis, overall prediction error, and percentage of agreement between the ML predictions and subjective refractions for different thresholds (0.25 D, 0.5 D).

RESULTS

All models considerably outperformed the predictions from the autorefractor, while ASB obtained the best results. The accuracy of the predictions for each individual power vector component was substantially improved resulting in a ± 0.63 D, ±0.14D, and ±0.08 D reduction in the 95% limits of agreement of the error distribution for M, J₀, and J₄₅, respectively. The wavefront-aberrometry related variables had the biggest impact on the prediction, while demographic and measurement quality-related features showed a heterogeneous but consistent predictive value.

CONCLUSIONS

These results suggest that ML is effective for improving precision in predicting patient's SR from objective measurements taken with a low-cost portable device.

Advancing the Sustainable Development Goals through improving eye health: a scoping review

UN member states have committed to achieving the Sustainable Development Goals (SDGs) by 2030. This Review examines the published evidence on how improving eye health can contribute to advancing the SDGs (beyond SDG 3). We identified 29 studies that showed direct benefits from providing eye health services on SDGs related to one or more of poverty (SDGs 1, 2, and 8), education (SDG 4), equality (SDGs 5 and 10), and sustainable cities (SDG 11). The eye health services included cataract surgery, free cataract screening, provision of spectacles, trichiasis surgery, rehabilitation services, and rural community eye health volunteers. These findings provide a comprehensive perspective on the direct links between eye health services and advancing the SDGs. In addition, eye health services likely have indirect effects on multiple SDGs, mediated through one of the direct effects. Finally, there are additional plausible links to other SDGs, for which evidence has not yet been established.

Biaxial Estimation of Biomechanical Constitutive Parameters of Passive Porcine Sclera Soft Tissue

This study assesses the modelling capabilities of four constitutive hyperelastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine' slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96%. The polynomial (anisotropic) model gave the best correlation of 98%. However, the estimated material parameters varied widely from one test to another such that there would be need to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be need to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters, thereby making it an easier option for application of its material parameters to a finite element model and requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy was more influenced by the fiber-related properties than the background material matrix-related properties.

Vision Impairment and Productivity Among Female Garment Workers in Bangladesh: A Cohort Study

PURPOSE

To assess the prevalence of near and correctable distance visual impairment among screened participants in the garment industry and to explore associations with income, age, and urban versus rural residence.

METHODS

Vision screenings were conducted at 4 garment factories, 2 urban and 2 rural locations during September and October 2019. Distance vision impairment was the presence of uncorrected vision of <6/12 in either eye, correctable to ≥6/7.5 with distance refraction. Near vision impairment was defined as 1 or more of the following: 1) either eye with presenting near vision 6/12 in the same eye; 2) having been prescribed near add spectacle power in examination records; and/or 3) clinical diagnosis of presbyopia at the time of screening. Demographic information and monthly income were self-reported by questionnaire completion.

RESULTS

Among 915 participating workers (100% female, 18 to 70 years), 29.2% (n = 267) and 26.8% (n = 245) had correctable distance and near vision impairment respectively. Prevalence of near vision impairment was significantly higher among rural residents (34.2%, n = 160), compared to urban (19.0%, n = 85, P < 0.0001) with the largest differences in the 35 to 39 (68.2% vs 44.2%, P = 0.0019) and 40+ (85.9 vs 48.9%, P < 0.0001) year age ranges. Prevalence of near vision impairment was already high among urban (20.4%, n = 20) and rural (23.0%, n = 17) workers aged 30 to 34 years. In simple linear regression models, participants with near vision impairment earned $13.3 [standard error (SE) 2.44, P < 0.0001] less per month than those without, while urban residents earned $40.6 (SE 1.74, P < 0.0001) more than rural dwellers. In the final multivariate linear model, both near vision impairment ($6.51 lower monthly earnings, SE 1.84, P = 0.0004) and urban residence ($43.2 higher monthly earnings, SE 2.39, P < 0.0001) remained significantly associated with income.

CONCLUSIONS

This study found high rates of near vision impairment among female garment workers, particularly rural dwellers, and at a younger age than expected. The high prevalence and association between near vision impairment and lower income suggest that focusing on industries with a high proportion of female workers, such as readymade garments, may be effective in addressing gender disparities in vision impairment and its economic impact.

Delivering Refractive Care to Populations With Near and Distance Vision Impairment: 2 Novel Social Enterprise Models

ABSTRACT

Vision impairment due to refractive error affects crucial time periods across the life course-the educational years for children and working years for adults. Refractive error is easily and safely corrected with glasses, but many potential beneficiaries remain uncorrected due to various barriers, which can be addressed with innovative service delivery models. This review describes evidence-based initiatives from 2 social enterprises, Peek Vision and VisionSpring, addressing barriers to refractive error correction in children and working adults, particularly in low-resource settings. The reach, implementation challenges, adoption, and future development of these 2 novel models are described, and research evidence of program effectiveness is presented.

Near vision impairment among the elderly in residential care-the Hyderabad Ocular Morbidity in Elderly Study (HOMES)

BACKGROUND/OBJECTIVE

To report on the prevalence and risk factors for near vision impairment (NVI) among the elderly in residential care in Telangana State in India.

METHODS

Individuals aged ≥60 years were recruited from 41 'home for the aged' centres in Hyderabad, India. All participants had complete eye examinations including presenting and best-corrected visual acuity assessment for distance and near. NVI was defined as binocular presenting near vision worse than N8 (6/15) among those who had a normal presenting distance visual acuity of 6/18 in the better eye.

RESULTS

Of the 826 participants, the mean age was 74.4 years (standard deviation-8.4 years), 525 (63.6%) were women, 715 (86.6%) had at least school education. The prevalence of NVI was 51.2% (95% CI: 47.7-54.7) based on presenting vision. On applying multiple logistic regression analysis, the odds of NVI were higher in 80 years and older age (OR: 2.17; 95% CI: 3.44-13.6). Those with school education (OR: 0.58: 95% CI: 0.36-0.94) and higher education (OR: 0.38; 95% CI: 0.21-0.69) had lower odds for NVI. Similarly, those with self-reported diabetes (OR: 0.69; 95% CI: 0.49-0.97), those using spectacles (OR: 0.09; 95% CI: 0.05-0.16), and those who had undergone cataract surgery (OR: 0.51; 95% CI: 0.36-0.74) had lower odds for NVI.

CONCLUSIONS

NVI was common among the elderly in residential care in homes for the aged in Hyderabad, India. As most of this NVI is correctable, a routine screening programme and dispensing of spectacles can be undertaken to address this vision loss.

Factors affecting guardians' decision making on clinic-based purchase of children's spectacles in Nigeria

BACKGROUND

This study aims to understand the key factors influencing guardians' decisions when purchasing spectacles for their children in semi-urban and urban areas of Cross River State, Nigeria, where a spectacle cross-subsidisation scheme will be implemented.

METHODS

This cross-sectional study was conducted among all consecutive guardians visiting the Calabar (urban), Ugep, Ikom and Ogoja (semi-urban) public eye clinics in Cross River State, southern Nigeria, from August 1 to October 31 2019, and whose children had significant refractive errors (myopia ≤-0.50D, hyperopia ≥1.50D, astigmatism >0.75D) and received spectacles. Guardians were interviewed using a questionnaire which included i) close-ended questions on reasons guardians choose to purchase spectacles for their children in eye clinics, ii) guardians' perceptions of the quality and design of children's current spectacle, iii) factors most heavily influencing their choice of spectacles for children, and iv) open-ended questions to seek guardians' suggestions on how to improve the current spectacle range.

RESULTS

All 137 eligible guardians (67.2% women [n = 92]) who visited the selected eye clinics participated in the study (response rate = 100%), with 109 (79.6%) from semi-urban and 28 (20.4%) attending urban clinics. Guardians from both urban and semi-urban clinics prioritised frame design, quality, and material as the main factors affecting their decision when purchasing spectacles for their children. Female guardians and those with higher incomes were both 1.5 times more likely to emphasise frame quality when describing selection criteria for purchasing spectacles for their children than male guardians (p = 0.01) or guardians earning less (p = 0.03).

CONCLUSION

Design, material, and frame quality are key factors influencing guardians when purchasing spectacles for their children in these setting and female guardians or those with higher income prioritise frame quality. This study could guide the planning and implementation of a novel cross-subsidisation scheme in Cross River State.

The Economic Impact of Presbyopia

Presbyopia is the world's number one cause of vision loss with more than 1 billion individuals affected globally. The total global costs associated with correcting near vision impairment due to uncorrected presbyopia have been estimated at $30.8 billion for a comprehensive eye care model. Both cost to the patient and cost to society, which is greater in low-income countries relative to high-income areas, should be considered. Ultimately, surgical correction of the nonaccommodating dysfunctional natural lens may provide the "cure" for presbyopia. Presbyopia-correcting intraocular lenses (IOLs) may provide better visual acuity and fewer adverse effects. Patients are pursuing cataract surgery at a younger and younger age. Although this expands the viable pool for lens exchange, this younger group of patients has extreme demands and has a much more scrutinizing frame of reference for comparison (a milder cataract). Thus, they are at a much higher risk for dissatisfaction and have a much higher chance of noticing potential adverse effects from multifocal IOLs. Setting appropriate expectations and thoroughly educating patients preoperatively helps create a partnership with the patient and a strong foundation for a successful surgical outcome. A cure for presbyopia has always been considered the holy grail of ophthalmology. In 2021, ophthalmologists are moving closer to achieving this goal while also creating a safer, more productive, cost-effective solution to presbyopia on an individual and on a global level. [J Refract Surg. 2021;37(6 Suppl):S17-S19.].

Presbyopia - A Review of Current Treatment Options and Emerging Therapies

Presbyopia is a common age-related vision disorder characterized by a progressive inability to focus on near objects. If uncorrected or under-corrected, presbyopia can significantly impact patients' quality of life. Presbyopia represents an area of considerable unmet need due to its rising prevalence worldwide as the population ages, the high proportion of under-treated individuals in some parts of the world, and the limitations of currently available corrective methods. Progressive or bifocal spectacles are associated with peripheral blur, a restricted visual field and impaired depth perception, which have been linked to an increased risk of falls in the elderly. Contact lens options can be difficult to maintain due to the development of age-related dry eye symptoms and reduced manual dexterity. Other corrective methods involve surgical interventions that modify the optics of the cornea, replace the crystalline lens, or attempt to restore active accommodation. While patients undergoing surgery report satisfactory outcomes post-operatively, many of them eventually require reading glasses. Non-invasive therapies with novel mechanisms of action are currently being investigated; these include miotic agents and UNR844, a lipoic acid choline ester. In this narrative review, available evidence on presbyopia prevalence, quality of life impact and risk factors are described, with a focus on observational studies in non-clinical settings. The diagnosis pathway and patient journey in presbyopia are outlined, and various treatment options are analyzed. The data reviewed herein reveals significant gaps in the provision of vision correction for this common condition, with a paucity of effective, non-invasive treatment options broadly accessible to presbyopic individuals.

Global economic productivity losses from vision impairment and blindness

BACKGROUND

In the absence of accessible, good quality eye health services and inclusive environments, vision loss can impact individuals, households and communities in many ways, including through increased poverty, reduced quality of life and reduced employment. We aimed to estimate the annual potential productivity losses associated with reduced employment due to blindness and moderate and severe vision impairment (MSVI) at a regional and global level.

METHODS

We constructed a model using the most recent economic, demographic (2018) and prevalence (2020) data. Calculations were limited to the working age population (15-64 years) and presented in 2018 US Dollars purchasing power parity (ppp). Two separate models, using Gross Domestic Product (GDP) and Gross National Income (GNI), were calculated to maximise comparability with previous estimates.

FINDINGS

We found that 160.7 million people with MSVI or blindness were within the working age and estimated that the overall relative reduction in employment by people with vision loss was 30.2%. Globally, using GDP we estimated that the annual cost of potential productivity losses of MSVI and blindness was $410.7 billion ppp (range $322.1 - $518.7 billion), or 0.3% of GDP. Using GNI, overall productivity losses were estimated at $408.5 billion ppp (range $320.4 - $515.9 billion), 0.5% lower than estimates using GDP.

INTERPRETATION

These findings support the view that blindness and MSVI are associated with a large economic impact worldwide. Reducing and preventing vision loss and developing and implementing strategies to help visually impaired people to find and keep employment may result in significant productivity gains.

FUNDING

MJB is supported by the Wellcome Trust (207472/Z/17/Z). JR's appointment at the University of Auckland is funded by the Buchanan Charitable Foundation, New Zealand. The Lancet Global Health Commission on Global Eye Health was supported by grants from The Queen Elizabeth Diamond Jubilee Trust, Moorfields Eye Charity (GR001061), NIHR Moorfields Biomedical Research Centre, The Wellcome Trust, Sightsavers, The Fred Hollows Foundation, The SEVA Foundation, The British Council for the Prevention of Blindness and Christian Blind Mission. The funders had no role in the design, conduct, data analysis of the study, or writing of the manuscript.

Near-vision impairment and effective near-vision spectacle coverage in two districts in Telangana, India: a population-based cross-sectional study

OBJECTIVES

To investigate the prevalence of near-vision impairment (NVI) and effective spectacle coverage for near vision in those aged ≥40 years in Khammam and Warangal district in Telangana, India.

DESIGN

A population-based cross-sectional study.

SETTING

Khammam and Warangal district in Telangana, India.

PARTICIPANTS

Of 6000 people enumerated, 5357 were examined (89%). 4526 participants without distance vision impairment were included in the analysis.

MAIN OUTCOME MEASURES

The study teams visited selected households and conducted eye examinations. NVI was defined as binocular presenting near vision worse than N6. 'Unmet need' was deemed to be present if the unaided near vision was worse than N6 and improved to N6 with near correction among the participants who did not have spectacles for near vision. 'Met need' was deemed to be present when unaided near vision was worse than N6 but improving to N6 with their spectacles. The 'undermet need' was deemed to be present when aided near vision was worse than N6 but improved to N6 with correction. Based on these definitions, e-near-vision coverage (%) is calculated as follows: e-NVC (%)=met need/(met need+undermet need+unmet need) × 100.

RESULTS

The mean age was 53.5 years (SD: 10.8 years), 2534/4526 (55.8%) were women, 1819/4526 (41.8%) had at least primary school education and 2368/4526 (52.3%) were from the Khammam district. The prevalence of NVI was 55.8% (95% CI 72.5 to 75.1; n=3343). Overall, the e-NVC (%) was 31.8%. It was 40.0% in Khammam and 23.2% in Warangal.

CONCLUSION

NVI is common in Khammam and Warangal districts in Telangana with inadequate effective near-vision coverage. Effective service delivery models are needed to reach out and provide services to address NVI to achieve universal eye health coverage in the region.

Barriers and Facilitators to Obtaining Eyeglasses for Vulnerable Patients in a Michigan Free Clinic

SIGNIFICANCE

Uncorrected refractive error is the main cause of visual impairment globally. Understanding barriers and facilitators underserved individuals face in obtaining eyeglasses will help address high rates of uncorrected refractive error.

PURPOSE

The purpose of this study was to understand the barriers and facilitators to obtaining eyeglasses among low-income patients in Michigan.

METHODS

Participants older than 18 years with hyperopia, myopia, or presbyopia and without active eye disease, severe mental illness, or cognitive impairment at Hope Clinic, Ypsilanti, Michigan, were included in this study. The participants answered a sociodemographic survey and underwent autorefraction and an interview. Interviews were audiorecorded, transcribed, and analyzed by two investigators.

RESULTS

Interviews were completed by 43 participants, and 30 participants' interviews were analyzed. The mean ± standard deviation age of 30 participants was 55 ± 12 years, 70% were female, 57% were African American, 40% had high school diploma or less, 57% earned less than U.S. $25,000 per year, 93% had worn glasses previously, and 87% had some medical insurance. Uncorrected visual acuity was logMAR 0.73 ± 0.61; best-corrected visual acuity was logMAR 0.16 ± 0.21. Thematic saturation was reached after 25 transcripts. Top barriers to using eyeglasses were cost (312 mentions, 29 participants), negative experiences with eyeglasses (263, 29), and limited access to eye care (175, 27). Top facilitators were positive experiences with glasses (230, 29), easy access to eyeglasses (143, 27), and availability of transportation (65, 27). Most participants (97%, 29) reported being negatively impacted by uncorrected refractive error. Most (97%, 29) were skeptical about obtaining eyeglasses online because of possible prescription problems.

CONCLUSIONS

Key barriers to correcting uncorrected refractive error in our community span across multiple health domains but are predominately rooted in external factors such as cost and access to vision care. Online eyeglasses may address access issues, but many participants were uncomfortable or unable to obtain glasses online.

Oral administration of resveratrol or lactic acid bacterium improves lens elasticity

A decrease in the elasticity of the ocular lens during aging is associated with loss of the accommodative ability of the eye, leading to presbyopia. Although near vision impairment is a social issue affecting the length of healthy life expectancy and productivity of elderly people, an effective treatment to improve near vision has not yet become available. Here we examined the effect of Enterococcus faecium WB2000, Lactobacillus pentosus TJ515, and resveratrol on lens elasticity in rats, where the stiffness of the ocular lens increases exponentially during the aging process. A combination of WB2000 and resveratrol improved lens elasticity not only in the long term but also with just short-term treatment. In addition, TJ515 decreased stiffness in the eye lens with long-term treatment. Therefore, the oral administration of WB2000 and resveratrol or TJ515 may be a potential approach for managing the progression of near vision impairment.

The value and implementation of routine ophthalmic examination in the era of HAART

BACKGROUND

The high prevalence of ocular manifestations (OMs) in patients with human immunodeficiency virus (HIV) infection and chronic diseases such as diabetes has become a global health issue. However, there is still a lack of an appropriate ophthalmic diagnostic procedure for the early detection of OMs in this population, leading to the risk of an irreversible visual impairment that substantially affects the quality of life of these patients.

METHODS

The Guangzhou HIV Infection Study was a retrospective study that enrolled hospitalised HIV-infected patients in Guangzhou between January 2005 and December 2016, period corresponding to the highly active antiretroviral therapy (HAART) era in China. We collected data on OMs, systemic diseases, hospitalisation, and demographic characteristics. We classified the patients into 3 groups according to the ophthalmic examination mode they underwent: the non-ophthalmologist examination group (patients hospitalised in 2005-2011 who were only treated by infectious disease physicians), the on-demand ophthalmic examination group (patients hospitalised in 2012-2013 who were referred for a consultation with an ophthalmologist), and the routine ophthalmic examination group (patients hospitalised in 2014-2016 who routinely underwent standard ophthalmic examinations). Binary logistic regression models were used to investigate the factors related to OMs.

FINDINGS

A total of 8,743 hospitalised HIV-infected patients were enrolled. The prevalence of detected OMs were 1.5% in the non-ophthalmologist examination group, 1.9% in the on-demand ophthalmic examination group, and 12.8% in the routine ophthalmic examination group. The odds of detection of OMs were highest in the routine ophthalmic examination group (adjusted odds ratio [aOR]=9.24, [95%CI, 6.51-13.12], compared to the non-ophthalmologist examination group). The detection of all types of OMs increased substantially, with keratitis, retinitis and vascular abnormalities increased the most (by 15.8-20.0 times). In the routine examination group, patients who were older than 50 years, males, with medical insurance, and were not resident in Guangzhou, had higher odds to have OMs. Several systemic diseases also increased the odds of OMs, with the highest odds among patients with a cytomegalovirus infection (aOR=5.59, [95%CI, 4.12-7.59]). Patients with retinitis, retinopathy and conjunctivitis had higher odds of having a CD4⁺ T cell counts less than 200 cells/μL compared to the patients that did not have these referred OMs.

INTERPRETATION

The implementation of a routine ophthalmic examination has improved the odds of OM detection by approximately 9 times and increased the diagnosis rates of all types of OMs. Therefore, we encourage all HIV-infected patients to undergo regular ophthalmic examinations. Patients with OMs, especially retinopathy and retinitis, need to be evaluated for immune function (such as CD4⁺ T cell counts) and systemic diseases.

Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study

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 <N6 or <N8 at 40 cm where best-corrected distance 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.

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.