A recent study published in The Lancet Global Health modeled global and regional estimates of effective refractive error coverage (eREC) to evaluate progress toward the World Health Organization’s (WHO’s) 2030 goal.
Give me some background.
Uncorrected refractive error is a major public health problem globally. Case in point:
- 3.7 million people (95% uncertainty interval [UI]: 3.1-4.3) are classified as blind (presenting visual acuity [PVA] < 3/60 in the better eye)
- 157 million people (95% UI: 140-175) have moderate or severe vision impairment (PVA < 6/18 to 3/60)
- 509.7 million people (95% UI: 371.1-666.6) have near vision impairment due to uncorrected or under-corrected presbyopia
- The growing myopia epidemic may foreshadow a future increase in vision loss due to pathological myopia and associated conditions
So with this in mind …
In 2024, WHO included eREC into the results framework of the 14th General Programme of Work, which outlines a roadmap for global health and guides WHO’s work from 2025-2028.
- Note: eREC is a measure of both the availability and quality of refractive correction in a population.
- It’s defined as the proportion of people in need of refractive error correction who have received services and have a good quality outcome.
Tell me more.
Countries with a baseline effective coverage rate < 60.0% were encouraged to adopt the national target of a 40 percentage-point increase in eREC by 2030.
Meanwhile: Countries with a baseline effective coverage rate > 60.0% were encouraged to strive for universal coverage, and—to reduce inequalities±place a greater focus on increasing effective coverage in their traditionally underserved population subgroups.
Now talk about the study.
In this systematic review and meta-analysis, the Vision Loss Expert Group, composed of over 70 specialists, analyzed data from 237 population-based eye surveys conducted in 76 countries since 2000—comprising a total of 815,273 participants.
The Group calculated eREC and the relative quality gap between eREC and REC (see here).
Country-age-sex group estimates were aggregated to provide estimates according to Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) super-regions.
And the findings?
In 2023, the global eREC was estimated to be 65.8% (95% UI: 64.7-66.8%), which was 6 percentage points higher than in 2010 (59.8% [95% UI: 59.4-60.2%]).
There were notable differences in eREC between GBD super-regions in 2023, ranging from 84.0% (95% UI: 83.0-85.0%) in high-income countries to 28.3% (95% UI: 26.4-30.4%) in sub-Saharan Africa.
Let’s dig deeper.
Since 2000, the relative increase in eREC per GBD super-region was as follows:
- Sub-Saharan Africa: 60.2%
- North Africa and the Middle East: 45.7%
- Southeast Asia, east Asia, and Oceania: 41.5%
- South Asia: 40.3%
- Latin America and the Caribbean: 16.2%
- Central Europe, eastern Europe, and central Asia: 8.3%
- High-income super-region (North America and western Europe): 6.8%
The relative quality gap ranged from 2.9% to 78.3% across studies, with larger gaps characteristically occurring in regions with lower eREC.
Moreover: Globally, the percentage of those with a refractive need that was undermet reduced between 2000 and 2023 from 10.0% (95% UI: 9.5-10.5%) to 5.3% (95% UI: 5.1-5.5%), respectively.
How did gender and age impact eREC?
In all super-regions, eREC was lower in females than males, and declined with increasing age among adults aged ≥50 years.
The highest levels of distance eREC in 2023 were in the high-income super-region (85.1% [95% UI: 84.1-86.0%] for males vs. 83.0% [95% UI: 81.9-84.0] for females).
- Conversely: The lowest level of distance eREC in 2023 was in sub-Saharan Africa (29.9% [95% UI: 27.9-32.0%] for males vs. 26.8% [95% UI: 24.9-28.8] for females).
Expert opinion?
An additional factor affecting eREC is suboptimal quality in prescribing and dispensing spectacles.
For example: “57% of people in a study from Pakistan had only the spherical component of distance spectacles tested, and only 35% of the single-vision distance spectacles dispensed to those in a study from Cambodia met all quality components in both lenses”.
Limitations?
These included:
- A level of caution must be exercised in interpreting country-level data given the heterogeneity of data sources and data sparsity in some countries and at different time points
- Only 17% (42 of 237) of studies in the dataset were nationally representative, with the remained being subnational and only six countries had nationally representative studies at two timepoints
Tie it all together for me.
These findings suggest that the current trajectory of improvement in eREC and the relative quality gap are insufficient to meet the WHO’s 2030 target.
- Further: No region is close to achieving universal coverage.
Global efforts to equitably increase spectacle coverage, such as the WHO SPECS 2030 initiative, and to address equity failings associated with geography, age, and sex, are crucial to accelerating progress towards the 2030 targets.