1. Research Department, Asociación para Evitar la Ceguera en México I.A.P, Mexico City, Mexico
2. Cell Biology Department, Advanced Research Center, I.P.N. (CINVESTAV), Mexico City, Mexico
3. School of Medicine, Instituto Tecnológico de Estudios Superiores de Monterrey, Mexico City, Mexico
4. Biochemistry Department, Universidad Nacional Autónoma de Mexico, School of Medicine, Mexico City, Mexico
5. Department of Ophthalmology, University of Colorado, Denver, CO, USA