e a lens. For the tutorial, we
will use the UPDATE LENS level commands. So much for listing the
current lens. Now, let's change something. All changes to the lens
database or "current lens" are made at the LENS UPDATE level. At that
level, most of the LENS INPUT level commands may be issued. There are
three additional commands, <strong>CHG</strong>, <strong>INS</strong>,
and <strong>DEL</strong>, which are unique to the LENS UPDATE
level. These commands are described in the User's Reference Manual. In
order