Perkins Mk3 Instruction Manual Issue 4

en Contents

1. Introduction... 2 1.1 Technical Description... 2 1.2 Purpose of Use... 3 1.3 Brief Description of the Appliance... 3

2. General Layout... 4/5 3. Safety and Regulatory Information... 6 3.1 Safety Notices... 6 3.2 Measuring Prism Replacement... 7 3.3 Transportation and Storage...8 3.4 Notes on Usage... 8 3.5 Statutory Requirements... 9 3.6 Caution... 9 3.7 Regulatory Information: CE Mark... 9 3.8 Regulatory Information: UL Mark... 10 3.9 Environmental Conditions of Use... 10 3.10 EMC (Electromagnetic Compatibility) Declaration... 11 3.11 Product Labelling and Safety Symbols... 12 3.12 Safety Symbols... 12

4. Taking a Pressure Measurement...13/14 5. To Prepare the Prism for Use... 15 5.1 Remove Perkins Mk3 Tonometer From Case... 15 5.2 Doubling Prism... 15 5.3 To Insert Prism into Prism Holder... 15 5.4 Tonosafe Disposable Prism... 15

6. Operating the Equipment... 16 6.1 Preparing the Patient... 16 6.2 Instruction to the Patient... 17

7. Cleaning the Equipment... 18 8. General Notes... 19 8.1 Astigmatism... 19 8.2 To Use the Instrument on Animals... 20 8.3 Special Precautions... 20

9. Measurement... 21 9.1 Sources of Error... 23 9.2 Inaccurate Horizontal Centering... 24 9.3 Inaccurate Vertical Centering... 25 9.4 Inaccurate Pressure... 26

10. Case Contents... 27 11. Calibration Check... 28 12. Storage of Prism and Tonometer... 29 13. Charging the Battery... 30 14. Battery Pack... 30 15. Charger Unit... 31 16. Technical Specifications... 31 References... 32 Accessories... 33

en 1. Introduction We would like to thank you for your decision to purchase this CLEMENT CLARKE product. If the instructions in this manual are carefully followed, we are confident that this product will give you reliable and trouble-free usage. We will be forced to disclaim any warranty and liability if the instrument is altered in any way or if routine maintenance is neglected or not carried out according to factory specifications. Only original CLEMENT CLARKE accessories are to be used to ensure continued reliability of the instrument. Following the popular Mark 2 Perkins tonometer, comes the technically advanced and well designed Mark 3 model. Its improved LED illumination and convenience are some of the many features which maintain the reputation of Perkins hand-held instruments in the forefront of tonometry. Because the Perkins tonometer is capable of being used in all positions, the mass of the Goldmann doubling prism must be controlled accurately. Only HAAG-STREIT prisms should be used or the disposable Tonosafe prism can be used to prevent cross-infection. Any other prisms may give a false reading if used in the Perkins tonometer.

1. 1

Technical Description

A pair of spiral wound flat springs connected in series are progressively tensioned by rotation of the operator’s calibrated thumb-wheel. The resulting force stored in the spring is transmitted through a balanced arm to the applanation doubling prism or the Tonosafe prism mounted at its end. The tonometer is fitted with two cobalt blue LEDs, (wavelength 450-490nm) to provide illumination. These are powered by a 3.6V, 280 mAh Ni-Mh rechargeable battery. The LED meets the requirements for a Class 1 LED product to IEC/EN 60825-1 (2001) under normal operating conditions and those of single fault failure. The battery charger conforms to Class II insulation and has also been tested to EN60601 and UL60601-1. This equipment is designed and manufactured to be as safe as is reasonably practicable when installed and used correctly by persons qualified to do so in accordance with the manufacturer’s instructions. Any misuse, incorrect assembly or installation could result in the equipment becoming unsafe. It must not be repaired except by competent persons under the manufacturer’s instructions.

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en 1. Introduction - continued 1. 2

Purpose of Use

Applanation Tonometers are used at room temperature in the examination, diagnosis and documentation of the human eye. Applanation tonometry may only be performed by healthcare professionals who are qualified by their respective authorities to do so.

1. 3

Brief Description of the Appliance

The Applanation Tonometer functions according to the “Goldmann” method: The measuring of the pressure required to maintain a uniform applanation of the surface of the cornea.

Advantages

• High accuracy of the measurement - the average deviation in any one single examination does not exceed ± 0.5 mm Hg. • The intraocular pressure in mm Hg is found by multiplying the drum reading by ten. • Scleral-rigidity is not to be taken into account as the small volumetric displacement of 0.56 mm3 increases the intraocular tension by about 2.5% only. • Massage effect DOES occur if repeated measurement occurs. • There are no standardization and calibration difficulties.

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en 2. General Layout 3

1

2

Fig 1 1 2 3 4 5 6

Forehead rest Forehead rest locking screw Forehead rest stem Prism holder Doubling prism Illumination LEDs

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5

6

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en 2. General Layout - continued

Fig 2 7 8 9 10 11 12

Viewing lens Milled thumb-wheel Scale Tonogrip (Cone arm securing buttons) Battery Indicator Charging Port

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10

8

9

11

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en 3. Safety and Regulatory Information 3. 1

Safety Notices No user serviceable parts inside. Do not open the Tonometer case moulding under any circumstances. Caution: In the event of any malfunction, contact your local distributor or visit our website to contact us directly. Use only the charger supplied with the device. This product is intended for indoor use only. This product is not suitable for operation in the presence of a flammable anaesthetic mixture with air or with oxygen or with nitrous oxide. Not protected against the ingress of water or other fluids.

The following instructions should be observed to ensure the safety of patients: Avoid examinations in cases of eye infections or injured corneas • There is no known contraindication for performing tonometry. Medical assessment is necessary and due care is to be exercised in cases of eye infections and injuries to the cornea.

Only clean and disinfected measuring prisms should be used • Examinations should be conducted with cleaned and disinfected measuring prisms. • Tonometer prisms are not dispatched in a disinfected state and should always be disinfected before use. • The disinfecting of contact glasses e.g. with cotton wool or a damp cloth without putting them into disinfecting fluid is insufficient and should not be allowed. • Incorrect medical disinfecting can cause patients to be infected and can also cause damage to the eyes. • Residue from the disinfecting may cause a caustic reaction to the patient’s eye, therefore rinse thoroughly.

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en 3. Safety and Regulatory Information - continued No damaged prisms should be used Before each use the contact surface of all prisms should be checked for contamination or damage (such as scratching, rips or sharp edges). A slit lamp microscope or Loupe is best used for this purpose, at a magnification of 10x to 16x. • If cracks form, the disinfectant may get into the hollow interior and can enter the patient’s eye while tonometry is taking place, leading to irritation of the cornea. Defective measuring prisms should not be used, to avoid any damage to the patient’s cornea.

3. 2 Measuring Prism Replacement • Due to the number of variables involved - type and concentration of disinfecting material used, number of patients, handling etc. - it is almost impossible to put a figure on the number of times and/or period of time that a measuring prism can safely be used for. • Our experience, and that of our users, indicates that under ‘normal’ usage (i.e. as per the instructions contained within this instruction manual) a maximum of two years provides an adequate safety factor. • HAAG-STREIT therefore recommend strongly that no measuring prism is used beyond two years from it’s date of first usage (a measuring prism may be retained as a spare indefinitely - deterioration does not start until it is first used). • The recommended time is overruled if the prism is in any way damaged within this time period - damaged prisms should be immediately discarded.

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en 3. Safety and Regulatory Information - continued 3. 3 Transportation and Storage • The Applanation Tonometer conforms to ISO 15004-1:2006 for Storage and Transport Conditions and should always be stored in its carry case when not in use.

Transport Conditions

Temperature: Relative Humidity: Atmospheric Pressure: Vibration, Sinusoidal: Shock: Bump:

Storage Conditions

Temperature: Relative Humidity: Atmospheric Pressure:

-40˚C to +70˚C 10% to 95% 500hPa to 1060hPa 10Hz to 500Hz: 0.5g 30g, duration 6 ms 10g, duration 6 ms -10˚C to +55˚C 10% t0 95% 700Pha to 1060hPa

• The Applanation Tonometer should be checked for damage after unpacking. • Defective equipment should always be returned in appropriate packaging. • The equipment may only be operated with the listed accessories (see page 33) according to the corresponding operating instructions. • The battery charger is exempt from the above standard but has been tested for Transport Conditions only within the carry case.

3. 4 Notes on Usage • Only qualified and trained personnel may operate the equipment. • The training of the operating personnel is the responsibility of the equipment user. • This type of sensitive measuring equipment should be checked after exposure to external force (e.g. unintentional shocks or being allowed to fall) and if necessary, should be returned to the manufacturer for repair. • The manufacturers of the equipment will not be liable for any loss or damage resulting from unauthorized intervention. In particular, it is forbidden to loosen any screws; this may reduce the accuracy of the measurement. All ensuing warranty claims will be deemed null and void as a result of unauthorized intervention. • The Perkins Mk3 should not be used while connected to the battery charger. 8

en 3. Safety and Regulatory Information - continued 3. 5 Statutory Requirements • The Applanation Tonometer is designed as a Class IIa device under the Medical Device Directive 93/42/EEC. • The Applanation Tonometer complies with the Tonometer regulation ISO 8612:2009 & ISO 15004-1: 2006.

3. 6 Caution • The safety regulations displayed in the operating instructions are to be observed with special care. Caution Strictly observe all warning notices!

3. 7

Regulatory Information: CE-Mark The products fulfil the requirements according to the following standards: Safety:

EN60601-1 Part 1: General Requirements for Safety, Medical Electrical Equipment

Electrical:

EN60601-1-2 Part 2: Collateral Standard: Electromagnetic Compatibility

Infrared:

EN60825-1 Part 1: Safety of Laser Products: Equipment classification requirements

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en 3. Safety and Regulatory Information - continued 3. 8

Regulatory Information: UL Mark

The UL Classification Mark: 4CH8 on our products signifies that they have been evaluated by Underwriters Laboratories for compliance with both Canadian and U.S. requirements as specified below:

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Usage:

Hospital and Optician use only

USA:

WITH RESPECT TO ELECTRIC SHOCK, FIRE AND MECHANICAL HAZARDS ONLY IN ACCORDANCE WITH UL 60601-1 UL Control number: 4CH8

Canada:

WITH RESPECT TO ELECTRIC SHOCK, FIRE AND MECHANICAL HAZARDS ONLY IN ACCORDANCE WITH CAN/CSA C22.2 No. 601.1 UL Control number: 4CH8 Medical equipment certified for Canada.

Environmental Conditions of Use Temperature:

+10˚C to +35˚C.

Relative Humidity:

30% to 90%

Atmospheric Pressure:

800hPa to 1060hPa

Shock (without packing):

10g, duration 6 ms

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en 3. Safety and Regulatory Information - continued 3. 10 EMC (Electro Magnetic Compatibility) Declaration With the increased number of electronic devices such as PC’s and mobiles, medical devices in use may be susceptible to electromagnetic interference from these devices. Which may result in incorrect operation of the medical device and create a potentially unsafe situation. Medical devices should also not interfere with other devices. In order to regulate the requirements for EMC with the aim to prevent unsafe product situations, the EN60601-1-2 standard has been implemented. This standard defines the levels of immunity to electromagnetic interferences as well as maximum levels of electromagnetic emissions for medical devices. Medical devices manufactured by Haag-Streit-UK Ltd conform to this EN60601-1-2 standard for both immunity and emissions. Nevertheless, special precautions need to be observed: The use of accessories and cables other than those specified by Haag-Streit-UK Ltd, with the exception of cables sold by Haag-Streit-UK Ltd as replacement parts for internal components, may result in increased emission or decreased immunity of the device. The medical devices should not be used adjacent to or stacked with other equipment. If adjacent or stacked use is unavoidable, the medical device should be seen to operate normally as it should in this situation. Further guidance regarding the EMC environment (in accordance with EN60601-1-2) in which the device should be used is available at: http://www.haagstreituk.com/medicalquality

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en 3. Safety and Regulatory Information - continued 3. 11 Product Labelling and Safety Symbols

The labels affixed to the equipment are there to remind you of safety precautions. Do not remove these labels.

3. 12 Safety Symbols The Perkins Mk3 Tonometer and its labels include the following markings:

!

Caution (Consult ‘Instructions for Use’)

0120

This product complies with the essential requirements of the medical devices directive (93/42/EEC). Compliance has been verified by UK notified body per 0120 (SGS United Kingdom Ltd). UL Classification Mark

4CH8

Do not dispose of with household refuse. Please contact your local authority for your nearest recycling centre. Manufacturer Direct Current (D.C.) Medical Electrical Equipment Type B

2010 e.g. SN0001 T3

Year of Manufacture Serial number Perkins Mk3 Tonometer (Example)

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en 4. Taking a Pressure Measurement The cornea is applanated with a measuring prism of organic glass that is fitted in a ring shaped holder at the end of the feeler arm. The contact surface of the measuring prism has a diameter of 7.0mm. It is planar with rounded edges to obviate any damage to the cornea. The measuring prism is brought into contact with the eye. The measuring drum is turned to increase pressure on the eye until a continuously regular surface of 3.06 mm ø = 7.354 mm2 has been applanated. Position of the measuring drum

Force

1

9.81 mN

Pressure 1.33 kPa =10mm Hg

The relationship between the measuring drum position, force and pressure on the applanation surface The intraocular pressure in mm Hg is found by multiplying the drum reading by ten.

SI-Units according to standard ISO 1000 mmHg

The conversion of mm Hg into the SI pressure unit kPa (Kilo Pascal) can be made on the comparison scale in Fig 3.

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The measurement of the flattened surface is made directly on the cornea. The built-in duplication system in the measuring prism divides the image and displaces the two semi circular halves from each other by 3.06 mm.

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The inner border of the ring represents the line of demarcation between the cornea flattened by applanation and the cornea not flattened.

20 1 Interval=1.471 mN

Before measuring, it will be necessary to anaesthetise the cornea locally, to place a strip of fluorescein paper in the conjunctival sac and switch on the blue filter of the tonometer.

0

40 50 60 70 80

k Pa

0 1 2 3 4 5 6 7 8 9 10

1 Interval=1.471 mN

According to ISO 1000 the derived unit of force is the N (Newton) and its decimal sub-multiple the mN (milli Newton).

HAAG-STREIT BERN

Fig 3 Comparative scale

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en 4. Taking a Pressure Measurement - continued The major advantage of applanation tonometry is the small bulbous deformation that amounts to only 0.56 mm3. The values found by this method of tonometry are only slightly influenced by scleral rigidity and radius of corneal curvature. The principle of applanation tonometry is simple. The careful construction of the apparatus is a guarantee of its continued correct performance. Nevertheless, in order to obtain exact results, the method of use indicated must be strictly followed. The readings obtained are based on the assumption that a cornea with a ‘normal’ thickness is being measured - alteration of the corneal thickness leads to changes in the measured IOP. A ‘normal’ corneal thickness is considered to be within the area of 530-560 microns. There is no universally agreed formula for the adjustment of the measured tonometry reading against altered corneal thickness. The users should bear these two facts in mind and keep themselves informed, through the current literature, with regard to the various formulae for adjusting measured tonometry readings in the event of thinned, or thickened, corneas being measured.

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en 5. To Prepare the Prism for Use 5. 1 Remove Perkins Mk3 Tonometer from case Remove the Perkins tonometer from the carrying case by holding the main body. Under no circumstances should it be lifted by the prism holder (Fig 1, 4).

5. 2 Doubling Prism The doubling prism (Fig 1, 5) should be prepared for use by cleaning following the cleaning instructions supplied with the prisms.

5. 3 To Insert Prism into Prism Holder

prism holder

prism

Tonogrip

Fig 4a 1. Lean the Tonometer back until the prism holder moves forward. (Fig 4a) 2. Gently pinch together the Tonogrip (cone arm securing buttons) (Fig 4a) on either side to hold the prism holder in position.

Fig 4b 3. With Tonogrip (cone arm buttons) pressed and the prism holder out (Fig 4b) the prism can be pushed into place.

N.B. Failure to follow these instructions could result in severe damage being caused to the instrument.

5. 4 Tonosafe Disposable Prism Alternatively, Tonosafe disposable prisms may be used. These are supplied as sterile single use items to help eliminate the risk of cross infection. Tonosafe and the prism holder have the same mass as the original doubling prism, so no conversion of results is required. The disposable prism can be inserted in the same manner as above.

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en 6. Operating the Equipment Caution It is imperative to read chapter 3. Safety and Regulatory Information, and to observe its precautions before operating the equipment. Perfect functioning can only be guaranteed with the use of an original HAAGSTREIT prism or Tonosafe. Sterilized fluorescein paper strips should always be used, as pathogenic exciters thrive well in fluorescein solutions. Regular calibration of the Tonometer is advised. Do not use without prism fitted.

6. 1 Preparing the Patient 1. Both eyes must always be anaesthetized (e.g. 2-3 drops each of an anaesthetic within half a minute) to reduce movements of the lids during examination. 2. Place a fluorescein paper strip near the external canthus in the lower conjunctival sac. After a few seconds the lacrimal fluid is sufficiently coloured and the paper can be removed. Alternatively combined anaesthetic fluorescein eye drops can be used. When using drops, a solution of sodium fluorescein 0.25% to 0.5% is advisable.

Caution: If the prism touches the cornea without any force applied, the pressure arm can vibrate and may disturb the patient. For this reason, the scale is set to read 1 before applying the prism face to the cornea. The Perkins tonometer should be held so that the thumb rests on the milled wheel ( Fig 2, 8) controlling the spring. The light is switched on by turning the thumb-wheel until the scale reading (Fig 5) is just above zero. If the forehead rest (Fig 1, 1) is to be used, the stem (Fig 1, 3), should be extended after loosening the locking screw (Fig 1, 2). When the forehead rest is correctly positioned, tighten the locking screw and the instrument can then be brought towards the patient so that the face of the prism cone comes into contact with the cornea. It is usually easier to hold the tonometer obliquely with the handle slanted away from the nose (Fig 6). Care should be taken to prevent the prism touching the eyelid margin.

Fig 5

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en 6. 1 Preparing the Patient - continued When seen through the viewing lens (Fig 2, 7) the semicircles of fluorescein should now be clearly visible and appear equal in size, denoting that the contact point is central on the cornea. The light is switched off by turning the thumb-wheel until the scale reading (Fig 2, 9) is below zero.

Note: The lighting is designed to give optimum fluorescence only when the prism cone is at its calibrated position i.e. when the rim of the prism holder is level with, or not more than 1 mm above the case surface.

6. 2 Instruction to the Patient

Fig 6 Instruct the patient to look straight ahead or slightly upward and if necessary use a fixation light for this purpose. It is recommended that patients are repeatedly asked to keep their eyes wide open during the examination. If required, the lids of the examined eye may be held open by the examiner’s fingers provided that no pressure is applied to the eye.

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en 7. Cleaning the Equipment Cleaning (manual) – non-immersion for Ophthalmic medical devices. Scope of Action Non-immersion manual cleaning methods are appropriate for low risk items (those items that come into contact with intact skin or do not contact the patient) where soaking in aqueous solution, e.g. electrical and electronic equipment, will compromise the device. Alcohol wipes should be used to clean electrical contacts on equipment. Equipment required: 1. A warm water/detergent solution at correct/recommended dilution. 2. A clean, disposable, absorbent, non-shedding cloth for application of detergent solution. 3. A clean, disposable, absorbent, non-shedding cloth for drying equipment. 4. An appropriate chemical neutraliser, first aid kit and eyewash, in case of splashing with detergent. Procedure: Ensure that it is disconnected from the charger and the unit is switched off (pointer reaches just below zero) before commencing the cleaning procedure. Wearing protective clothing, immerse the cleaning cloth in the detergent solution and wring thoroughly. Commencing with the upper surface of the item, wipe thoroughly ensuring that detergent solution does not enter the electrical components. Periodically rinse the cloth in clean water and repeat the above steps. Surfaces should be carefully hand-dried using a fresh dry cloth. Note: Non-immersion, manual cleaning is not a disinfection process, but where an alcohol wipe is used to dry surfaces, this may have a disinfecting effect. Safely dispose of cleaning materials and alcohol wipes, if used. The above was written with reference to: Sterilization Disinfection and cleaning of Medical Devices & Equipment: Guidance on Decontamination from the Microbiology Advisory Committee to the Department of Health Medical Devices Agency (MAC manual section 2 page 20 updated April 2005)

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en 8. General Notes Note

Only the shortest possible measuring time periods should be carried out on each eye. Should drying of the cornea epithelium be observed, then vision and field of sight should be checked in advance. The measuring procedure can be repeated several times. Excited or anxious patients often display a higher ocular pressure during the first measurement. For this reason, a reduction of tension is experienced during the first few minutes, as patients notice that tonometric examinations cause no unpleasant effects. A test measuring procedure should therefore be first made on each eye. These results can be disregarded. Thereafter, three measuring procedures are to be carried out on each eye. The readings will be correct when the pressure has been stabilised. When measuring procedures have been correctly carried out, divergences in the results will be only of the order of ± 0.5 mm Hg. When the measuring procedure lasts too long on one eye, drying will occur on the cornea epithelium of both eyes. A ring of fluorescein-positive deposits around the contact positions of the cornea and the measuring element will occur on the eye under examination. On the other eye, map-like fluorescein-positive dried places will occur, which will not allow a reliable measuring procedure. Extensive drying phenomena disappear after a short time without treatment becoming necessary. Focused vision will be affected by such fine epithelium defects.

8. 1 Astigmatism If the cornea is spherical, measurements can be made on any meridian, but it is most convenient to do it on the 0˚ meridian. This is not so when eyes with higher corneal astigmatism that 3 dioptres are examined, as the 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 mm) is to applanated, when the measuring prism is at an angle of 43˚ to the meridian of the greatest radius.

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