Hashemi H, Heydarian S, Hooshmand E, et al. - Utilizing a structured search strategy from two sources, four electronic databases (PubMed, Web of Science, Google Scholar, and Scopus) and the reference lists of the selected articles have been explored from inception to June 2018 with no limitations and filters, researchers conducted this systematic review and meta-analysis to ascertain the prevalence and risk factors for keratoconus worldwide. Three thousand nine hundred ninety-six articles have been retrieved, 29 of which have been analyzed. The sample consisted of 7,158,241 candidates from 15 countries. Data reported that keratoconus prevalence in the whole population was 1.38 per 1,000 population. In studies reporting gender, keratoconus prevalence was 20.6 per 1,000 in men and 18.33 per 1,000 in women. The odds ratio of eye rubbing, keratoconus family history, allergy, asthma, and eczema, respectively, was 3.09, 6.42, 1.42, 1.94, and 2.95. Findings revealed that keratoconus had a low prevalence in the world. According to the available evidence, the most important risk factors for keratoconus were eye rubbing, family history of keratoconus, allergy, asthma, and eczema.