the capacity to understand a broad range of topics; "a teacher must have a breadth of knowledge of the subject"; "a man distinguished by the largeness and scope of his views"
the eye unaided by any optical instrument that alters the power of vision or alters the apparent size or distance of objects; "it is not safe to look directly at the sun with the naked eye"
increased pressure in the eyeball due to obstruction of the outflow of aqueous humor; damages the optic disc and impairs vision (sometimes progressing to blindness)