KERATOMETRY

The proper technique should be used to obtain accurate readings:

adjust eyepiece
calibrate instrument
properly position patient
properly position and focus 
   the mires
accurately align mires for  
   measurement
may make 2 or 3 measurements 
   on each eye
extend the range of the instrument 
   if necessary


Remember that the keratometer reads from 2 points on the cornea approximately 3.0 mm apart.