We thank Chang and colleagues for their thoughtful comments and interest regarding our article. We would like to clarify several points.
We agree that projection studies should be interpreted in light of their underlying assumptions. However, the issues largely reflect inherent limitations of the currently available global epidemiological evidence, rather than deficiencies specific to our projection framework. These assumptions and limitations were acknowledged in our original article. They do not, however, undermine the rationale or value of the projection, which aimed to estimate the potential public-health implications of rising myopia prevalence for open-angle glaucoma (OAG) using the best available data.
First, baseline OAG risk among non-myopic individuals may change with screening practices, diagnostic criteria, or healthcare access. Nevertheless, assuming a relatively stable baseline risk is commonly used in previous projections of OAG burden. Available epidemiological evidence suggests that age-specific OAG prevalence has remained relatively stable over recent decades. Consistently, our analysis found no significant differences in OAG prevalence among studies conducted before 2000, between 2000 and 2010, and after 2010 ( P =.87), supporting the use of a relatively stable baseline risk in the projection model.
Second, regarding the transportability of the myopia–OAG association, the best available meta-analytic evidence has not demonstrated statistically significant differences in effect estimates according to ethnicity, including Asian vs Western populations ( P =.80), or geographic region ( P =.06). Therefore, the use of a pooled risk estimate is supported by current evidence. Although glaucoma susceptibility increases with myopia severity in a dose-dependent manner, severity-stratified projections require reliable projections of myopia prevalence according to refractive error severity. Such data are currently available primarily for East Asian populations, whereas comparable data from many other regions are limited. More granular projections would be desirable but are not currently feasible because sufficient global data are lacking.
Third, age-related effect modification is an important consideration because age is a major determinant of OAG risk and may influence the association between myopia and OAG, particularly in individuals with high myopia. However, incorporating age-specific risk estimates into a global projection framework requires robust age-stratified effect estimates from large population-based studies across diverse regions. Most existing studies report overall risk estimates rather than age-specific associations, and evidence regarding age-specific risk estimates remains limited. In the absence of sufficiently reliable age-stratified data, introducing age-specific parameters would increase model complexity without necessarily improving validity.
Although these limitations should be recognized, incomplete evidence should not preclude efforts to quantify the potential public-health implications of rising myopia. Our study provides a timely, evidence-informed estimate of the contribution of increasing myopia prevalence to future OAG burden, supporting clinical awareness, public-health planning, and research prioritization. Although uncertainty remains regarding the precise magnitude of the projections, the available evidence supports the overall conclusion that rising myopia prevalence is likely to contribute substantially to the future global burden of OAG, and future studies incorporating more detailed severity-, age-, and region-specific data will further refine these estimates.
CRediT authorship contribution statement
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