OPHTHALMOMETER MEASURING TECHNIQUE Aligning the Instrument The patient's eye level should be at the level with the pointer on the side of the instrument. To do this the instrument is moved to one side by using the joystick so the examiner can sight along side the instrument, aligning the pointer with the center of the patient's eye. See next screen to adjust height. Be sure to loosen the base lock to allow the intrument to be moved.