Dr. Daniel Casper practices general, medical ophthalmology full-time at Columbia University Medical Center, dividing his time between the Naomi Berrie Diabetes Center and the Harkness Eye Institute Faculty Practice. His ophthalmology training, including residency and fellowship, has all been done at Columbia, and he has been affiliated with the university in various capacities since 1986.

After completing his residency, Dr. Casper was a fellow in orbital and oculoplastic Surgery with Dr. Stephen Trokel at Columbia, and along with Dr Linda Chi of the Radiology department, co-edited the textbook, "Orbital Disease: Imaging and Analysis," on which Dr. Casper served as senior editor and illustrator. In 2019, Drs. Casper and Cioffi co-edited the book, "The Columbia Guide to Basic Elements of Eye Care: A Manual for Helathcare Professionals." Dr. Casper also was the senior editor and illustrator on this book.

Although Dr. Casper practices comprehensive, non-surgical ophthalmology, he specializes in diabetic eye disease, and is Director of Ophthalmology at the Naomi Berrie Diabetes Center at Columbia University Medical Center. He is currently a Professor of Ophthalmology at CUMC, and in addition to his patient care responsibilities, he regularly teaches medical students enrolled at the College of Physicians and Surgeons, as well as residents in ophthalmology, internal medicine and family practice medicine, and fellows training in endocrinology.