Despite high-quality evidence being essential for planning and delivering eye health programmes, evidence on what works is relatively scarce. To address this need, we developed eye health evidence gap maps (EGMs), with the first one focusing on cataracts. These maps summarise, critically appraise and present evidence in a user-friendly format. This paper presents experiences of developing the cataract gap map and discusses the challenges and benefits of the process. Following a comprehensive search of relevant databases, we sifted and extracted data from all relevant reviews on cataracts. A total of 52 reviews were included in the map. The majority of the reviews addressed quality of clinical care (20) and types of treatment (18). Overall, 30 reviews provided strong evidence in response to the research question, 14 reviews showed weak or no evidence, and in 14 reviews the results were inconclusive.