Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia

Methodological quality of the review: Low confidence

Author: Timothy R. Fricke, Nina Tahhan, Serge Resnikoff, Eric Papas, Anthea Burnett, Suit May Ho, Thomas Naduvilath, Kovin S. Naidoo

Region: Worldwide

Sector: Refractive error

Subsector: Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia

Equity focus: No

Study population: All ages

Type of programme: global prevalence

Review type: Other review

Quantitative synthesis method: Systematic review and meta-analysis

Qualitative synthesis method: Not applicable

Background: Presbyopia was estimated to affect more than one billion people globally in 2005, with more than half unable to access the necessary refractive correction to overcome the associated vision impairment (VI). Data for presbyopia correction rates similarly were limited, and correction estimates similarly uncertain. In addition to the paucity of evidence, the authors noted a need to increase consistency in presbyopia prevalence study methodology to enable comparability. New prevalence and spectacle-correction data, together with improved modelling techniques based on newer demographic data, warrant updated global presbyopia estimates and projections.

Objectives: The aim of this study was to update global and regional presbyopia prevalence and spectacle-correction coverage estimates based on new epidemiologic evidence and improved modelling.

Main findings: 25 studies were included in the analysis of the prevalence of presbyopia and 43 studies were included for spectacle coverage. The global estimates of prevalence and people with presbyopia cover from 2000 through 2050. In 2000, presbyopia was estimated to affect 1.4 billion people, that is, 23% of the world population (95% CI, 1.3-1.5 billion [22%-24%]). In 2015, we estimate presbyopia affected 1.8 billion people, that is, 25% (95% CI, 1.7-2.0 billion [23%-27%]). The global crude suggests that all-ages prevalence of presbyopia is predicted to peak soon after and then start to decrease. We predict that the number of people affected by presbyopia will continue to increase because of population growth, until peaking at approximately 2.1 billion in 2030. By 2050, we predict a decrease to 1.9 billion, that is, 20% (95% CI, 1.6e2.3 billion [19%-21%]). Prevalence of presbyopia is estimated to be higher in regions with longer life expectancies, whereas the greatest burden of VI resulting from uncorrected presbyopia occurs in low-resource countries. Globally, we estimated that there were 826 million people (95% CI, 686-960 million people) with VI resulting from uncorrected, or inadequately corrected, presbyopia in 2015.

Methodology: Inclusion criteria included: 1) population-based studies quantifying presbyopia prevalence; 2) presbyopia defined as unaided near vision worse than N6 or N8 at 40 cm or customary working distance; 3) a mechanism to exclude people with eye disease causing reduced near vision; 4) sampling representative of entire communities; and 5) sample size of at least 400 participants, without date restrictions.

Record was identified through PubMed National library Medicine using MeSH terms. Articles that were not available in English were excluded. Seven additional articles were identified by key informants and reference lists of included studies. Analysis: We gathered the prevalence data into five-year age groups from 0 to 90 years or older. Published evidence covered all age groups 40 years or older in 11 of the 21 World Health Organization Global Burden of Disease (GBD) regions, plus the 35- to 39-year-old age group in six of the same regions. Authors meta-analysed the prevalence of presbyopia within each age group within each of the 11 GBD regions using Comprehensive Meta-Analysis version 3 (Biostat, Englewood, NJ). A logit random effects model was used to combine studies within each age group and region.

Applicability/external validity: Regarding external validity, the authors reported some limitations which need to be considered when using the results externally; they further added that data tends to be less reliable in low income countries where sampling is sometimes incomplete – there could be location and ethnicity effects that have not been detected in this analysis. Hyperopia was not considered in the modelling. The estimates of refractive correction rates are reliant on the accuracy of country-level HDI, Gini coefficient and health expenditure data.

Geographic focus: Worldwide, but this data is not reliable in LMIC.

Summary of quality assessment:

Overall, there is low confidence in this review’s findings. Searches were not thorough enough to ensure that all potentially relevant studies were identified, and it is not clear from the review which studies were low risk and high risk of bias. These limitations impact on study findings’ validity and reliability.

This review has missing methodological points. The search period was not highlighted in the article. The authors did not report on how quality assessment was done. No appendix on link for quality assessment was present in the text. Additionally, no specification was reported on the number of people who did the screening and data extraction.