Dominus illuminatio mea

Dominus illuminatio mea is the incipit of Psalm 27 and is used by the University of Oxford as its motto. It has been in use there since at least the second half of the sixteenth century, and it appears in the Coat of [arms of the University of Oxford|coat of arms of the university].
An article written in 2000 by the Roman Catholic priest and theologian Ivan Illich may help to explain this ancient university motto, at a time when scientists were progressively replacing the concept of vision as a gaze radiating from the pupil by the concept of vision as the retinal perception of an image formed by reflected sunlight:

Other uses

Dominus illuminatio mea is also the motto of Loyola High School in India, founded in 1961.
It is one of the two mottos of Robert College in Istanbul, and it has appeared in the arms of the Robert College Alumni Association since 1957, next to Veritas.
In the US, it is the motto of Cair Paravel-Latin School, a private college-preparatory school in Topeka, Kansas. It is also used Finlandia University, St Leo's College, University of Queensland, and by Drew University in Madison, NJ.
In Hong Kong, it is the motto of Marymount Secondary School.