Z8A9F9 | IFU323EN00
INSTRUCTIONS FOR USE
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Fig 30 - Microscope observed image
6
Slowly turn the tonometer measurement knob until the
semicircles will be perfectly aligned.
Fig 31 - Correct semicircles alignment
4.10
HOW TO MEASURE THE INTRAOCULAR PRESSURE IN
ASTIGMATIC PATIENTS
In case of irregular cornea, measurements can be taken on any
meridian.
In case of patients with astigmatism greater than 3 dioptres, the choice
of the prism position considering the flatter meridian is significant to
improve the measurement accuracy.
The Goldmann tonometry
,
to measure the real intra-ocular pressure,
is based on the principle of applanation of a surface of 7,354 mm
2
with
3.06 mm diameter from the center of the cornea.
The prism's semicircles are therefore reached sooner in the flatter
meridian than in the steeper one. The problem can be overcome
rotating the prism to 43°, on red sign positioned on the prism holder,
in the respect of the flatter meridian.
