ng></p>

<p>Experiment with other changes to the lens using other UPDATE LENS
  level commands described in the LENS section.</p>

<h3>Query of Lens Values During Lens Input and Update</h3>

<p>During LENS INPUT and LENS UPDATE, typing a lens parameter name
followed by a space and a question mark will result in the current
value of that parameter being displayed on the screen. For example,
while at surface 3, typing:</p>

<p><strong>
    RD ?<br>
</strong></p>

<p>will result in the radius of curvature of s