Uncorrected refractive error is the leading cause of vision impairment in child and adult populations. In recognition of the large unmet need for care, coupled with the fact a highly cost-effective intervention exists (i.e. spectacles), WHO Member States endorsed the first-ever global target for refractive error at the Seventy-fourth World Health Assembly (2021): https://apps.who.int/gb/ebwha/pdf_files/WHA74/A74(12)-en.pdf

Proportion of people who have received refractive error services (i.e. spectacles, contact lenses or refractive surgery) and have a resultant good quality outcome relative to the number of people in need of refractive error services.

Age (population aged 50 years and above) , sex, geography (e.g. urban vs non-urban) and socioeconomic status.

Here is the formula:

\[ \frac{a+b}{a+b+c+d} \times 100 \]

Note: all visual acuities are measured for distance. Presenting visual acuity (PVA) is the measure of unaided vision; or, if spectacles or contact lenses are worn to the assessment, visual acuity is measured with the person wearing them. Best-corrected visual acuity (BCVA) is assessed either by pinhole or refraction. For measuring uncorrected visual acuity (UCVA), if spectacles or contact lenses are worn to the assessment, visual acuity is measured with the person not wearing them.

Numerator:

1. Individuals with UCVA worse than 6/12 in the better eye who present with spectacles or contact lenses for distance vision and whose PVA is equal to or better than 6/12 in the better eye (“met need”).
2. Individuals with a history of refractive surgery whose UCVA is equal to or better than 6/12 in the better eye (“met need”).

Denominator:

1. Individuals with UCVA worse than 6/12 in the better eye who present with spectacles or contact lenses for distance vision and whose PVA is equal to or better than 6/12 in the better eye (“met need”).
2. Individuals with a history of refractive surgery whose UCVA is equal to or better than 6/12 in the better eye (“met need”).
3. Individuals with UCVA worse than 6/12 in the better eye who present with spectacles or contact lenses for distance vision and a PVA of worse than 6/12 in the better eye, but who improve to equal to or better than 6/12 on pinhole or BCVA (“undermet need”).
4. Individuals with UCVA worse than 6/12 in the better eye who do not have distance vision correction and who improve to equal to or better than 6/12 on pinhole or BCVA (“unmet need”).

-

Every 5 years

vision@who.int

Vision and Eye Care Programme

3154

The use of pinhole visual acuity to establish an individual’s BCVA is by no means equivalent to a refraction. Despite this, due to feasibility considerations, most existing rapid assessment survey methodologies use pinhole visual acuity as a proxy for BCVA.