Sightsavers Logo
Research centre
  • Home
  • About us
  • Research approach
  • Research studies and publications
  • Evidence gap maps
Join in:
  • Join in: Facebook
  • Join in: Twitter
  • Join in: Instagram
  • Join in: LinkedIn
  • Join in: YouTube
  • Global
    • Close search bar
    Donate
    • Home
    • About us
    • Research approach
    • Research studies and publications
    • Evidence gap maps

    Refractive error evidence gap map

    Kalpana gets her eyes tested in the Sundarbans.

    What this map shows

    At Sightsavers, our EGMs summarise, appraise, and present evidence from systematic or literature reviews.

    The refractive error gap map compiles evidence from 188 reviews. Five of these reviews cover more than one thematic area and were thus included in the EGM multiple times. Among these, 95 reviews address the treatment of refractive error, 53 tackle the burden of disease (epidemiology), and 19 cover risk/prevention of refractive error. The remaining reviews address screening (10), quality of life (four), quality of clinical care (four), cost benefit (four), quality of non-clinical care (four), and access to services (two). This gap map reveals clear evidence gaps at the health-systems sector level, with no reviews identified around access to healthcare services.

    In response to the authors’ research questions, 103 reviews provide strong evidence, 61 reviews present weak or no evidence, and 27 reviews yield inconclusive (mixed) results. The reviews were assessed for quality: 90 reviews are graded as low quality, 77 as medium quality, and 24 as high methodological quality.

    Find out more about the key messages from this EGM in our refractive error evidence brief.

    How to read an evidence gap map


    Read our how to guide

    Read our how to guide

    How much detail would you like to see?

    Sectors
    Burden of disease
    Biomedical
    Service Delivery
    Health Systems
    Impact/Economic Evaluation
    Strength of Evidence
    Epi
    Risk
    Treat
    C.Detect
    QCC
    QNCC
    Access
    Workforce
    Financing
    Leadership
    HMIS
    Tech
    QoL
    Cost
    Strong
    32
    12
    46
    3
    3
    1
    2
    4
    2
    Inconclusive
    2
    2
    18
    1
    1
    1
    Weak
    19
    4
    28
    8
    2

    Are we missing a systematic review?

    This evidence gap map was last updated in 2024.
    Help us keep this gap map up to date by sending us an email: gapmap@sightsavers.org

    Reference

    Sightsavers (2022). Refractive Error Evidence Gap Map [online] Available at: https://research.sightsavers.org/evidence-gap-maps/refractive-error-gap-map/

    Our research is guided by our five year strategy

    Our research approach
    Sightsavers Logo
    Research centre
    • Join in:
    • Join in: Facebook
    • Join in: X
    • Join in: Instagram
    • Join in: LinkedIn
    • Join in: YouTube

    Protecting sight, fighting disease and promoting equality for all

  • Accessibility
  • Sightsavers homepage
  • Our policies
  • Media centre
  • Contact us
  • Jobs
    • Cookies and privacy Terms and conditions Modern slavery statement Safeguarding

    © 2025 by Sightsavers, Inc., Business Address for all correspondence: One Boston Place, Suite 2600, Boston, MA 02108.

    Our website uses cookies

    To make sure you have a great experience on our site, we’d like your consent to use cookies. These will collect anonymous statistics to personalise your experience.

    Manage preferences

    You have the option to enable non-essential cookies, which will help us enhance your experience and improve our website.

    Essential cookiesAlways on

    These enable our site to work correctly, for example by storing page settings. You can disable these by changing your browser settings, but some parts of our website will not work as expected.

    Analytics cookies

    To improve our website, we’d like to collect anonymous data about how you use the site, such as which pages you read, the device you’re using, and whether your visit includes a donation. This is completely anonymous, and is never used to profile individual visitors.

    Advertising cookies

    To raise awareness about our work, we’d like to show you Sightsavers adverts as you browse the web. By accepting these cookies, our advertising partners may use anonymous information to show you our adverts on other websites you visit. If you do not enable advertising cookies, you will still see adverts on other websites, but they may be less relevant to you. For info, see the Google Ads privacy policy.