BACKGROUND There is controversy on when and in who recommend visual screening, the aim of this paper is to assess the level of evidence on the topic and compare it with current recommendations. METHODS Systematic review of scientific papers searching in Medline and Cochrane Library Plus, without date limit and only papers in English and Spanish. Grey literature accessed through manual search, no restrictions were made by study design. RESULTS There is a great variability in recommendations ranging from very restrictive to very lax. The vast majority were through clinical practice guidelines or opinion papers. The scientific paper identified, 2 were RCT, 3 non controlled trials, and one cross-sectional. CONCLUSIONS Professional associations should use scientific arguments instead of corporative ones. The studies on adults don't allow to determine if the recommendation made by associations are evidence based. In the case of children, the studies and the recommendations give no information on what is the ideal age to perform the screening.