Prevalencia de ojo seco en pacientes que acuden a la Clínica de Prevalencia de ojo seco en pacientes que acuden a la Clínica de Optometría de la FESI, UNAM * La presente investigación no depende de ningún proyecto institucional o subvención económica. En ella tampoco existe conflicto de intereses con los autores. ** BA in Optometry, in charge Prevalencia de ojo seco en pacientes que acuden a la ABSTRACT Objetive: To report the prevalence of dry eye and to determine the differences between young and adult patients attending the Optometry Clinic of the Iztacala School of Higher Education at Universidad Nacional Autónoma de México (UNAM). Material and methods: In 1957, patients between the ages of 15 and 65 assessed at the "Centro de Diagnóstico de Alteraciones de Superficie Ocular" of the Iztacala School of Higher Education of UNAM between August 2016 and August 2017. The patients answered the digital version of the Ocular Surface Disease Index (OSDI) diagnostic questionnaire and the mucin arborization pattern was evaluated using the Tear Ferning Test (TFT). Results: The mean prevalence of the diagnosis with a significant difference of positive P<0.05 for Ferning (59.1%) and OSDI (63.8%). Using the Ferning technique in young patients (15 to 29 years), it was possible to assess a prevalence of dry eye of 51.9%; whereas in adults (30 to 65 years) it was 66.9%. Using the OSDI questionnaire, the prevalence was 60.1% in young people and 67.8% in adults; in addition, for each year of increase in age, the probability of having a dry eye increased by 1% with OSDI and 2% with Ferning. Conclusions: With this study, it was established, for the first time, that the young people who go to the optometry clinic of FES-Iztacala, a sector that had not been previously considered, also suffer from this disease.