Greenspoon joined his father Reuben Greenspoon, also a contact lens specialist, in his practice Professional VisionCare Associates in 1951. In 1988 Greenspoon and Dr. Richard Silver joined as partners to form Professional VisionCare Associates and they worked in collaboration to create the technology for hand painted special effect soft contact lenses. As a still working optometrist, Greenspoon's practice is located in Sherman Oaks, California.