On July 13, 1976 following graduation from the School of Optometry in Waterloo, Dr. Fretz opened her Listowel office. It had been purchased from John Monaghan and included records going back to 1949. The following day, July 14, she opened a second practice in New Hamburg. In addition, for a number of years, she also owned a practice Wellesley.
Dr. Fretz was granted Fellowships in the American Academy of Optometry, the International Orthokeratology Society, and In April of 2015 the College of Optometrists in Vision Development. She is a member of the Ontario Association of Optometrists, the Canadian Association of Optometrists, and the College of Optometrists in Vision Development. Dr. Fretz is designated as a prescriber of topical therapeutic agents.