Your interviewers want to see if you understand the desired qualities and characteristics of a successful optometrist and are the kind of optometrist who embraces their values and whom they would be proud to count among their alumni. Their website states, "Pennsylvania College of Optometry at Salus University has an unparalleled legacy in the education of competent and compassionate Doctors of Optometry." Competence and compassion are two traits they value highly enough to mention.
Think about how you exhibit empathy and compassion and how that drives your pursuit in this field. You'll also notice when exploring the site that one of their keywords is 'innovation.' They pride themselves on continual innovation and scientific development through pioneering research. So, one can assume their definition of competence is staying ahead of the curve and being constantly informed on the most recent scientific developments in the field.
If you are interested in the research side of optometry, share this. Also, aligning your personality with the school's mission statement and values can go a long way. Consider these points when formulating your answer.