Dr John Mark de Leon finished his ophthalmology residency at Cardinal Santos Medical Center (Philippines) where he is a glaucoma consultant. He completed glaucoma clinical research fellowships at the Jules Stein Eye Institute, UCLA, at the Singapore Eye Research Institute, and at the Massachusetts Eye & Ear Infirmary, Boston. He is also affiliated with the East Avenue Medical Center, Dept of Health Eye Center, Philippines, where he is the Assistant Chair for Research.