What do ALM, APL, OVR, PCE and BLK mean on the NIDEK TONOREF II?

Q: What do ALM, APL, OVR, PCE and BLK mean on the NIDEK TONOREF II?

On the NIDEK TONOREF II, ALM means alignment error, APL means insufficient corneal applanation, OVR means the IOP exceeds the preset range, PCE means the APC range cannot handle substantial IOP fluctuation, and BLK means blinking or slight movement. Correct alignment or eyelid opening as indicated, or switch the measurement range when the manual specifies it.

The answer

On the NIDEK TONOREF II, ALM means alignment error, APL means insufficient corneal applanation, OVR means the IOP exceeds the preset range, PCE means the APC range cannot handle substantial IOP fluctuation, and BLK means blinking or slight movement. Correct alignment or eyelid opening as indicated, or switch the measurement range when the manual specifies it.

Filed under Error codes

The NT error code determines the next action:

ALM: perform alignment and measure again.
APL: ask the patient to open wider; an assistant may hold the lids open with a swab if necessary.
OVR: switch to APC 60 or 60.
PCE: switch from APC 40 to 40, or from APC 60 to 60.
BLK: repeat after the patient stops blinking or moving.

OVR and PCE are not interchangeable: the first is an out-of-range pressure result, while the second concerns fluctuation that defeats APC control.

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