1. University Institute of Tropical Diseases and Public Health of the Canary Islands, University of La Laguna, Avda Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Tenerife, Canary Islands, Spain
2. Department of Ophthalmology, Hospital Universitario de Canarias, Tenerife, Canary Islands, Spain
3. Laboratoire Matériaux-Molécules et Applications, IPEST, B.P. 51 2070 La Marsa, University of Carthage, Tunisia