Dr. Murchison Callender is a Professor Emeritus with the School of Optometry and Vision Science at the University of Waterloo known for research in the microbiology and physiology of the eye in contact lens wear and the clinical applications of contact lenses, and the investigation of the the anatomical and biochemical mechanisms associated with the refractive changes in the developing eye. In addition to an active research agenda, Callender is known for a long-standing clinical teaching practice and vision care programmes in the Caribbean.

Callender was born in the village of Sainte Madeleine in Trinidad and Tobago to George Elton Callender (1908-2008) and Dorothy Orgato Wilson Callender. His father worked as an accountant for the Usine Ste Madeleine Sugar Estate and later for the Trinidad and Tobago government, and his mother taught at a business school in San Fernando before opening her own business school. Callender attended primary school and high school in San Fernando and excelled in science. After completing high school, he worked for the Trinidad Texaco Oil Company as a Research Assistant.

Immigrating to Canada on September 5, 1958, to attend Sir George Williams University (now Concordia University) in Montreal, Quebec, as an undergraduate student, where he received his B.Sc. (Biology). Callender completed postgraduate work at the Royal Victoria Hospital in Montreal and developed an interest in the optometry, going on to join the College of Optometry in Toronto. In 1967, the College of Optometry moved to the University of Waterloo and Callender was part of the first graduating class from the School of Optometry at the University of Waterloo in 1968. In addition to optometry training, he also holds a M.Phil (Vision Sciences) from the University of Aston in Birmingham, England.

After graduating from Waterloo, Callendar worked as Assistant Optometrist at the School where he was involved with teaching and clinical aspects of optometry. His appointment as a full-time faculty member is believed to have been the first such appointment of a Black faculty member in optometry in Canada, and perhaps North America. Prior to retiring from the Waterloo, Callendar served in various administrative roles, including the Director of the Contact Lens Clinic and Admissions Officer, and spent several decades managing vision care programmes for people of the Caribbean in both Waterloo and on location, including in Jamaica.