First
,
light
travels
through
the
____________________
,
which
is
transparent
.
Then
,
it
passes
through
a
hole
called
the
____________________
,
which
is
surrounded
by
the
iris
.
After
that
,
it
passes
through
the
____________________
,
which
helps
the
eye
to
focus
.
Finally
,
it
reaches
the
____________________
.
