Cataract evidence gap map

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What this map shows

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

The cataract EGM summarizes evidence from 98 reviews, of which six have been included twice as they report on two thematic areas (e.g. treatment as well as QCC). Of the 98 reviews, four are pediatric-related cataract reviews and 94 are age-related cataract reviews.

The reviews are unevenly distributed across the sectors, with most addressing treatment of cataract (36), closely followed by clinical care (29) and risk factors and prevention of cataract (20). Very little evidence is identified in terms of access to cataract-related health care services (8), economic evaluations of interventions (3), epidemiology (5) and quality of life (3). Therefore, this gap map shows that there are clear gaps in evidence at the health systems sector level. No reviews are identified for cataract-related screening and quality of non-clinical care.

A total of 46 reviews are of low confidence, of which 27 provide strong evidence in response to the research question they set out to answer. 29 reviews on the map are of medium quality, where the majority (19) show strong evidence in response to their research question. Finally, a total of 29 reviews are of high confidence; 12 of these provide strong evidence in response to their research question and another 11 provide weak evidence. Very few reviews provide weak evidence in response to author’s research question, regardless of confidence level.

A special thank you to Dr. Baixiang Xiao for supporting in the review of studies written in Chinese.

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

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This evidence gap map was last updated March 2020.
Help us keep this gap map up to date by sending us an email: [email protected]


Sightsavers (2021). Cataract Evidence Gap Map [online] Available at: [Add date accessed]

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