If we position
our eyes on the eye-ring and the area of the pupil of our eye is
greater or equal to the area of the eye-ring, our eyes will collect
all the light refracted by the objective The precise location of
the eye-ring naturally depends on the separation between the
objective and the eye-piece When you view through a microscope
by placing your eyes on one end,the ideal distance between the
eyes and eye-piece is usually built-in the design of the
instrument 9