. 2019 Aug 28;12(4):240–247. doi: 10.1016/j.optom.2019.04.003
© 2019 Spanish General Council of Optometry. Published by Elsevier España, S.L.U.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).