The College of Optometrists

Does anyone know how the calibration is checked on the Nidek NT 3000 tonometer and it's method of pressure measurement (ie. is it time to applanate the cornea to max reflection of projected image or is there a direct pressure measuring transducer in the piston.) The store where I work has misplaced the manual and I have had trouble contacting Nidek for info.

its based on the same principle as the reichart nct in that it measures the time taken to applanate the cornea.

to calibrate it u need to open the small lid at the front and slide the switch onto the demo/test function. you then fire the tonometer and the screen should read "calibration okay".

i had the same trouble as u and went through many lengths to find this out. unfortunately they didnt even bother asking me about it last week which pissed me off.

oh and btw, after applanation has reached (i.e. peak stimulation at photoreceptor diode) the jet of air is cut off (unlike AO Mark I) so the eye dosnt receive the full blast.

Also where the px rests their head, there is a sensor which allows the instrument to get in sync with cardiac pulse. you need to be on a seperate mode to use this, and readings take longer.