15
EN
D-KAT Tonometer by KEELER
8. PROBLEM SOLVING
8.1 THE FLUORESCEIN RING IS TOO WIDE OR TOO NARROW
Cause:
The fluorescein semicircles are too wide.
The measuring prism was not dried after
cleaning, or the eyelids came into contact
with the measuring prism during
measurement. The pressure reading is higher
than the real intraocular pressure.
Correction:
Move the slit lamp back and dry the
measuring prism with a wad of sterile
cotton wool or lint free cloth.
Cause:
The fluorescein semicircles are too narrow.
The lacrimal fluid has dried during
prolonged measurement. The pressure
reading is lower than real ocular pressure.
Correction:
Move the Slit Lamp back and ask the
patient to close his / her eyes once or twice,
then repeat the measurement procedure.
8.2 THE MEASUREMENT PRISM DOES NOT TOUCH THE CORNEA OR TOO
MUCH FORCE HAS BEEN APPLIED
Cause:
If the patient pulls his / her head back even
slightly, the pulses will become irregular
and the measuring prism contact with the
eye will become intermittent. If the patient
pulls his / her head even further back, the
fluorescein semi-circles will completely
disappear.
Correction:
If possible, use a band to hold the patient’s
head in place.