Alicia Galán1, Noemí Roselló2. 1. Department of Ophthalmology, Joan XXIII Hospital, University of Rovira i Virgily, Tarragona, Spain Centro de Estrabismo, Clínica DYTO, Barcelona, Spain. 2. Department of Ophthalmology, Joan XXIII Hospital, University of Rovira i Virgily, Tarragona, Spain Centro de Estrabismo, Clínica DYTO, Barcelona, Spain. Electronic address: nrosello.bcn.ics@gencat.cat.