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© HAAG-STREIT AG, 3098 Koeniz, Switzerland - HS-Doc. No. 1500.7220067.04180 – 18. Edition / 2020 – 01
DEUTSCH
ENGLISH
FRANÇAIS
ITALIANO
ESPAÑOL
NEDERLANDS
PORTUGUÊS
SVENSKA
DEUTSCH
ENGLISH
FRANÇAIS
ITALIANO
ESPAÑOL
NEDERLANDS
PORTUGUÊS
SVENSKA
6. Snap the sensor arm into place so that the axes of the measuring prism and of
the microscope align.
7. Switch on the tonometer and set a value between 5 and 10 mm.
Model R and model BQ
1. Swing the illumination apparatus to the left.
2. Release the tonometer from the dwell position to the right of the microscope,
and swing it forward until it locks in the measuring position.
3. From the left, bring the illumination apparatus into contact with the tonometer
bearer arm. This is the only illumination position in which both the patient’s left
and right eyes can be easily examined (no 60° position). This arrangement fa‑
cilitates the splaying of the patient’s eyelids, should this be necessary for meas‑
urement. The illumination of the applanated surface through the measuring
prism is practically reflection-free.
Observation:
with model R in the left eyepiece
with model BQ in the right eyepiece
Model T
1. For an examination through the tonometer’s left or right eyepiece, the angle
between the illumination instrument and the microscope should be approx. 60°
so that the image is bright and reflection-free. Alternatively: lighting through the
measuring prism at approx. 10°.
5.7 Measuring correctly
1. Immediately before taking measurements, the patient should close his eyes
briefly so that the cornea becomes sufficiently moistened with fluorescein-im
‑
pregnated tear fluid.
2. By moving the slit lamp, the measuring prism comes into contact with the centre
of the cornea over the pupillary area.
3. During contact, the cornea's limbus takes on a bluish glow. This glow can be
best observed with the naked eye from the opposite side of the illumination ap‑
paratus.
4. When the limbus glows, stop moving the slit lamp immediately.
5. After contact is made, viewing is conducted through the microscope. The uni‑
form pulsation of the two semi circular fluorescein bands, which could be of dif
‑
ferent sizes in drum setting 1 depending upon inter‑ocular pressure, shows that
the tonometer is in the right measuring position.
6. Any necessary corrections are done using the slit lamp control lever, until the
flattened surface is observed in the form of two semicircles of similar size in the
middle of the visual field (A).
7. Smaller changes in the depth of the slit lamp using the control lever do not af‑
fect the size of the semicircles.
8. The pressure on the eye is increased by turning the tonometer knob until the in‑
ner borders of both fluorescein bands just touch = correct setting (B).
9. When the eye pulsates, both semi circles cross over each other.
10.
The width of the fluorescein band around the contact point of the measuring
prism should be about 1/10 of the diameter of the applanation surface (0.3 mm).
11. Display value in mm Hg.
(A)
(B)
NOTE!
If the tonometer is too close to the
eye, the color of the LED changes
to red and a warning tone alerts the
user to the fact that he has left the
measuring range and the sensor is
in the safety distance.
5.8 Sources of error
Ocular images
Fluorescein band incorrect
1 – 2
Wrong distance to patient
3 – 9
Position too far to the right/left
5 – 9
Position too high/low
10 – 14
Incorrect pressure
15 – 18
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