CALIBRATION OF THE 
               KERATOMETER

Mounting the Units on the Instrument


The stem that holds the calibration balls 
clamps onto the headrest of the instrument 
with a thumb screw.  It should be mounted 
as far up on the headrest as possible 
without getting onto the curved portion. 
Rotate it in towards the objective of the 
instrument so the ball is at about the 
location where the patient’s eye would be.  
The tendency is to have it too far away 
from the objective where it is impossible 
to get it in focus.

With the single bar type of calibration unit, 
it is either held in place by magnets onto 
the headrest or clamps onto the head rest.  
Again position it as close to where the 
patient’s eye level would be as possible.