When placing a lens on the patient’s 
left eye (assuming you are right 
handed and standing on the patient’s 
right side) place your left hand on the patient’s head as before but over the 
left eye.  Place your right hand on the patient’s left cheek as before being careful not to block the vision of the patient’s right eye as you want the patient to be able to maintain fixation 
on the distant target so they do not 
move their eyes when you are about 
to place the lens on the eye.

Do not try to change sides and be on the patient’s left when placing the left lens.  This wastes time, is awkward, and if it is being done in the examination room the instrument stand will be in the way.