Orthotes is a Greek philosophy concept which means approximately "an eye's correctness". In Plato

Plato

Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

's philosophy it is said to be the passage from the physical eyes to the eyes of the intellect.

At least this seems to be the interpretation of Martin Heidegger

Martin Heidegger

Martin Heidegger was a German philosopher known for his existential and phenomenological explorations of the "question of Being."...

 (as says Marilena Chaui

Marilena Chauí

Marilena de Souza Chaui is a Brazilian philosopher. She has been teaching political and modern philosophy in the Department of Philosophy of the University of São Paulo since 1967, when she presented her dissertation on Merleau-Ponty...

 in her philosophy classes at University of São Paulo

University of São Paulo

Universidade de São Paulo is a public university in the Brazilian state of São Paulo. It is the largest Brazilian university and one of the country's most prestigious...

) in his "Plato's Doctrine of Truth".

In his essay, "The End of Philosophy and the Task of Thinking," Heidegger distinguishes "Orthotes" from the similar Pre-Socratic concept, "Aletheia" ("unconcealment"), describing it as "the correctness of representations and statements."