10
DEUTSCH
ENGLISH
FRANÇAIS
ITALIANO
ESPAÑOL
NEDERLANDS
PORTUGUÊS
SVENSKA
© HAAG‑STREIT AG, 3098 Koeniz, Switzerland − HS‑Doc. no. 1500.7006000.04260 – 26. Edition / 2020 – 03
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 affect
the size of the semicircles.
8. The pressure on the eye is increased by turning the tonometer measuring drum
until the inner 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. Reading the scale value:
•
Reading the value
•
and multiplying by 10
•
yields the inter‑ocular pressure in mm Hg
(A)
(B)
5.7 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
Fluorescein band too wide (1)
1
The measuring prism was not dried after cleaning or the eyelids
came into contact with the measuring prism during measure‑
ment, or too much fluorescein has been used.
The slit lamp must be pulled back and the measuring prism
dried with a lint-free cloth (e.g., made of cellulose).
Fluorescein band too small (2)
2
The tear fluid dried during the longer-lasting measuring.
Allow the patient to close his eyes a few times and then re-
peat the measurement.
5.7.1 Wrong distance to patient
No semi circular image, only centre line is visible (3)
3
The measuring prism is not coming into contact with the cor‑
nea! If the patient draws his head back slightly, irregular pulsa‑
tions will be caused because the measuring prism is touching
the eye only intermittently. If the patient retreats even further,
the fluorescein rings will disappear completely.
Instruct the patient to adopt the correct position.
Only parts of both oversize semicircles are visible (4)
4
If the slit lamp is pushed too far against the patient, or if the
patient moves toward the slit lamp, the sensor arm will push
against a spring stop. The applanation surface is too large.
The image does not change when the measuring drum is
turned. Pull the slit lamp back until the uniform pulsations
of a correspondingly smaller surface show the correct mea-
suring position and pressure changes immediately cause
applanation surface changes.
5.7.2 Position too far to the right / left
Only part of the upper semicircle (5)
5
Measuring prism not centred on the eye, eye much too far to
the right.
Using the control lever, move the slit lamp to the right.
Whole upper semicircle – part of the lower semicircle (6)
6
Measuring prism not centred on the eye, eye still too far to the
right.
Using the control lever, move the slit lamp to the right.
1500_7006000_04260_Gebrauchsanweisung-AT-900_01_eng.indd 10
1500_7006000_04260_Gebrauchsanweisung-AT-900_01_eng.indd 10
19.03.2020 07:02:24
19.03.2020 07:02:24
