Keeler D-KAT Z, Инструкция по эксплуатации

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14
EN
D-KAT Z-Type Tonometer by KEELER
7.4 USING THE INSTRUMENT / TAKING A MEASUREMENT
Instructions to the patient
• The patient’s head must be firmly positioned on the chin rest and the forehead rest. If
necessary, a band may be used to hold the head still.
• Ask the patient to look straight ahead. If necessary, use a fixation target to keep the eyes still.
• We recommend occasionally reminding the patient during the examination, to keep his /
her eyes wide open. If necessary, the examiner may use the tips of his fingers to hold the
lids open, taking care not to exert pressure on the eye.
• When elevating the lids, the angle between the microscope and the lighting unit must be
reduced to about 10° so that the light beam passes through the body of the prism. In this
position it should be possible to obtain an image with no reflections.
• Immediately before measurement, ask the patient to close his / her eyes for a few seconds,
in order to ensure that the cornea be sufficiently wetted by the lacrimal fluid containing
the fluorescein solution.
Taking the measurement
• Move the Slit Lamp forward to bring the measuring prism into contact with the centre of
the cornea in the area above the pupil. The limbus will be illuminated with a bluish light. The
examiner will be able to better directly observe this phenomenon from the opposite side.
• As soon as the corneal limbus is correctly illuminated, immediately stop all forward
movement of the Slit Lamp.
• After contact is established, observe the cornea
through the microscope. When the measurement drum
is set to position 10 on the LED, the two semicircular
fluorescein rings (which will vary in size according to
the ocular pressure) will pulse rhythmically when the
Tonometer is in the correct position for measurement.
• Use the Slit Lamp joystick control to make any
corrections needed until the applanated surface is
observed as two semicircular surfaces of equal area
at the centre of the field of vision. (Figure 1). Small
adjustments downward made with the joystick will
have no effect on the sizes of the semicircular images.
• Increase the applanation pressure by rotating the Tonometer measurement drum until the
margins of the fluorescein rings touch and cross as the eye pulses (Figure 2). The width of
the fluorescein rings around the contact position of the measuring prism should be equal
to about 1/10 of the diameter of the applanation surface (0,3 mm).
Figure 1: Semicircular images at the
Centre of the field of vision.