r-defined and predefined operands. We will
make up a merit function which consists of the following
aberrations:</p>

<p><strong>Predefined:</strong> The Y-height on the image surface of
the full marginal Y-ray for an on-axis image position The PY marginal
paraxial ray height on surface 3</p>

<p><strong>User-defined:</strong> The PY marginal paraxial ray height
on surface 3 squared and added to the PCY chief paraxial ray height on
surface 3 squared. The difference between the X-ray heights of the FOB
1, RA