Structure and Specification Prism

T170R Applanation Tonometer

Prism Seat Within Accuracy Within Accuracy Out of Accuracy
User Manual Prism Seat
Test on position “ 2 ” with the Counterweight Seat on
Prism
1, Replace the Prism with the Counterweight Seat.
2, Set the Dial Drum at the number “ 2 ”.
3, Turn the Knob till the Prism Arm stays freely between the two extreme positions.
Mounting Rod
Prism Arm
4, If the scale line "2" is out of contact with the Basic Line, the tonometer is out of accuracy, shown
as below:
Dial Drum
Tonometer Body
Counterweight Seat
Turning Knob
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Range of Measurement: 0 mmHg ~ 80mmHg (0 kPa ~ 10.64kPa) Test on position “ 4 ” with 1 Counterweight on
Moving Range of the Rings： 1.53×2＝3.06mm。 1, Put one Counterweight in the Seat of the Counterweight.
Prism Diameter： 7mm。 2, Set the Dial Drum at the number “ 4 ”.
Moving Range of Prism： 0 ~ 3mm。 3, Turn the Knob till the Prism Arm stays freely between the two extreme positions.
Dimension： 190mm×80mm×80mm。 4, If the scale line "4" is out of contact with the Basic Line, the tonometer is out of accuracy, shown
Net Weight： 480g。 as below:
Working Temperature： 0℃～40℃ / 32℉～104℉。 Counterweight
Working Relative Humidity： 10%～85%。
Storage Temperature： 0℃～55℃ / 32℉～131℉。
Storage Relative Humidity: 10%～95%。
version： 1.0 Within Accuracy Within Accuracy Out of Accuracy
20140210 Installation Test on position “ 6 ” with 2 Counterweights on
serial number：2013-08-007 1, Keep 2 Counterweights in the Seat of the Counterweight.
Mounting the Tonometer onto the Slit lamp 2, Set the Dial Drum at the number “ 6 ”.
Shown as below: 3, Turn the Knob till the Prism Arm stays freely between the two extreme positions.
Tonometer
Acknowledgment 4, If the scale line "6" is out of contact with the Basic Line, the tonometer is out of accuracy, shown
as below:
Many thanks you for making the decision of purchasing our products known as the best Counterweight
price-performance and almost trouble-free products in the global market of Ophthalmic Instrument Mounting Screw
and Vision Machinery!
For having the smooth and pleasant experience in using our products, it is recommended to read the
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User Manual first after unpacking.
Mounting Adaptor Test on position “ 0” with 3 Counterweights on
Packing list Round Body type Slip Lamp
1, Keep 3 Counterweights in the Seat of the Counterweight.
2, Set the Dial Drum at the number “ 0 ”.
1, Applanation Tonometer (including Mounting Rod ) 3, Turn the Knob till the Prism Arm stays freely between the two extreme positions.
2, User Manual The Mounting Adapter provided in the packing is for the Slit Lamp with the round body only.
4, If the scale line "0" is out of contact with the Basic Line, the tonometer is out of accuracy, shown
3, Accessory Box (including Prism Arm x1, Prism x 3, Weight Seat x 1, Counterweight x 3 ) ( shown as above).
as below:
4, Mounting Adaptor (including Mounting Screw x 1 ) When coming across any problem with the Mounting Adapter, please contact your service or
Counterweight
supplier.
The Tonometer can also stay mounted on the Slit Lamp when not in use.

Accuracy Test Within Accuracy Within Accuracy Out of Accuracy

Applanation Accessory To ensure the reliability of the measurement, the test on the accuracy of the Tonometer is The Tonometer out of accuracy should be sent back to MediWorks for calibration.
Tonometer Caution: Any unauthorized attempt of calibration may cause the permanent damage to the
Box necessary at the first time when the Tonometer is to be used. The Accuracy Test should also
be carried out regularly after that. Tonometer.
Test on position “ 0 ” with the Prism on
1, Lay the Tonometer on a flat and firm surface with the Prism pointing upwards.
Measurement
2, Set the Dial Drum at the number “0”. Preparation of the equipment
3, Turn the Knob till the Prism Arm stays freely between the two extreme positions. 1, Install the Prism Arm onto the Tonometer, shown as (a);
4, If the scale line "0" is out of contact with the Basic Line, the tonometer is out of accuracy, 2, Insert the Prism gently into the Prism Seat, shown as (b);
User Mounting
shown as below:
Manual Adapter
 7, Repeat the measuring process above for 3 times on each patient. If the results are similar,
Prism Seat
180 the measurement is reliable.
Astigmatism
8, Clean the Prism with 3% Hydrogen Peroxide or 1:5000 Chlorhexidine solution and dry it If the cornea is spherical, measurements can be made on any meridian. It is most convenient to do it
up with cotton ball after the measurement. on the 0° meridian.
Prism This is not so when eyes with higher corneal astigmatism than 3 dioptres are examined, as the
How to solve the Problems in Measurement flattened areas are not circular but elliptic.
It has been calculated that, in cases of larger corneal astigmatisms, a surface of 7.354 mm2 (ø 3.06
(a) (b) Problem : The fluorescein rings are too fat ( Figure 3 ) mm) is to be applanated, when the measuring prism is at an angle of 43° to the meridian of the
3, Clean the prism with 1:32000 solution of Phenylmercuric Borate or other organic glass friendly Cause: The prism was not properly dried up after cleaning, greatest radius.
cleaning solution. Dry it up with cotton ball afterward; or the eyelids touched the prism while measuring. For example, if the corneal astigmatism amounts to
4, Mount the Tonometer onto the Slit Lamp. For the patient who has Astigmatism, it is necessary to Solution: Pull the Slit Lamp back to withdraw the prism. Figure 3 6.5 mm / 30° = 52.0 D / 30° and
adjust the axis of the prism accordingly. For the detail please read the chapter " Astigmatism "; Dry up the prism properly with a cotton ball and try again. 8.5 mm / 120° = 40.0 D / 120°
5, Set the number of the Dial Drum at " 1 "; the graduation value 120° of the prism is set at the red 43°
6, Adjust the the eyepieces of the Slit Lamp Microscope to get it focused; P: The fluorescein rings are too thin ( Figure 4 ) mark of the prism holder.
C: The cornea was in lack of lacrimal fluid. If there is a corneal astigmatism of
7, Position the illumination of the Slit Lamp and the Microscope in 40~60° angle to properly light
S: Pull the Slit Lamp back to withdraw the prism. 8.5 mm / 30° = 40.0 D / 30° and
up the Prism; Figure 4
Let the patient blink the eyes for a couple of times before 6.5 mm / 120° = 52.0 D / 120°
8, Open the slit light to the maximum into a round spot.; Figure 13
trying again. the graduation value 30° is set at the red 43° mark.
9, Switch the filter to the Cobalt Blue; In other words, set the axial position of the greatest radius, that is the axis of a minus cylinder, on the
10, Set the magnification at 10 x. P: The fluorescein rings are too large( Figure 5 ) prism graduation at the red mark on the prism holder.
Caution: The direct contact to the surface of the Prism with the finger or any kind of hard material C: The Slit Lamp and the Tonometer were too close to the cornea.
may cause the scratch on it. S: Pull the Slit Lamp and the Tonometer back into the correct position. Figure 5
Tips for the Measurement
Preparation of the patient
The result of the measurement could be affected if the patient drinks coffee, alcohol or too much
1, Both eyes must always be anesthetized to stop the movement of the eye lids during the
P: The lower Half-Ring looks larger than the upper one( Figure 6 ) water before the measurement. Body tension, holding breath or a tight collar of the patient could
measurement. For example 2-3 drops of 0.2% novesin or other anesthetic into each of the patient
C: The cornea is too low in position. also affect the measurement result.
eyes. Repeat it every 1 - 2 minutes for 2 - 3 times.
S: Raise the position of the cornea or lower the the position of the Prism. Different anaesthetics may also affect the result of the measurement. It is recommended to use
2, Place a fluorescein paper strip near the external canthus in the lower conjunctival sac for 2 - 3
Figure 6 0.2% Novesine or 0.5%-1% teracainum or 0.2% Dorsacaine
seconds till the lacrimal fluid is properly colored.
The value of first time measurement could be higher than the second time because of the tension of
3, Or using eye drop solution of sodium fluorescein 0.25 % to 0.5 % .
the patient.
4, Position the head of the patient on the chin rest.
P: The fluorescein ring appears on the left side( Figure 7 ) When measuring procedure is correctly carried out, the differences of the results in a run of
5, When the patient has problem of keeping the eyes open during the measurement, the fingers could
S: Move the Slit Lamp and the Tonometer leftwards. measurement on a patient should be within ± 0.5 mm Hg.
be used to assist, on the condition of without extra pressure on the eyeball. Figure 7 When the differences are within 1 mmHg value, take the average one.
Procedure of Measurement
During the measuring process, keep the eyelids and eyelashes of the patient out of contact with the
1, Right before the start of the measurement instruct the patient to blink the eyes for a couple of Prism.
times to moisten the cornea with the lacrimal fluid and the fluorescein. P:The rings are completely in the upper half( Figure 8 ) A measurement should be completed within 30 seconds to avoid coloration of the cornea.
2, Move the Slit Lamp gently forward till the surface of the prism contact the center part of the S: Move the Slit Lamp and the Tonometer upwards. Too frequent measurement in one run on one eye may result with the lower measurement value. It
cornea of the patient. Figure 8 is recommended to measure both eyes alternately.
3, Observe the cornea through the left side eyepiece of the microscope During the measurement the patient should focus on an object 5 meter away.
( for R type of MediWorks Tonometer ). The head of the patient should be kept still during the measurement.
Adjust the microscope till the two bluish Half-Rings are focused. 3-5 minutes interval is necessary when switching among the different Tonometers during a
P: The rings are on the right side ( Figure 9 )
( The Dial Drum is set at “ 1 ” ) ( Figure 1). Figure 1 Figure 2
measurement on a patient.
S: Move the Slit Lamp and the Tonometer rightwards.
4, Turn the Dial Drum slowly to add the pressure onto the cornea Figure 9
till the inner edges of the two Half-Rings meet. ( Figure 2). Maintenance
5, Read the number on the Dial Drum.
For the mmHg value or kPa value of the Intraocular Pressure please check the Conversion Table Before the measurement
P: The outer edges of the rings touch each other( Figure 10 ) Clean the prism with 1:32000 solution of Phenylmercuric Borate or other organic glass friendly
below against the read out from the measurement.
S: Increase the pressure till the inner edges of the rings meet. cleaning solution. Dry it up with the cotton ball afterward.
mmHg/kPa Value Conversion Table Figure 10
After the measurement
Read out mmHg value kPa value Clean the prism with 3% Hydrogen Peroxide or 1:5000 Chlorhexidine solution after the
1 10 1.33 measurement. Dry it up with cotton ball before putting it back into the accessory box.
P: The ends of the rings coincide to form a continued line ( Figure 11 )
2 20 2.66
S: Increase the pressure till the inner edges of the rings meet.
3 30 3.99 Figure 11
4 40 5.32
5 50 6.65
P: The inner edges of the rings miss each other ( Figure 12 )
6 60 7.98
S: Decrease the pressure till the inner edges of the rings meet.
7 70 9.31 Figure 12
0 80 10.64

6, Reset the Dial Drum at “ 1 ” for the next measurement.