Tonometer Calibration Guide Issue 2 July 2019

THE IMPORTANCE OF PERFECT CALIBRATION

Reliable results & reduced equipment downtime With eye clinics becoming increasingly busy it is vital that all tonometry equipment is maintained to the highest possible standard. Patient safety is critical, so it is imperitive that routine checks are completed regularly. This ensures that faults are quickly identified and that all measurements are accurate. Haag-Streit guidelines advise that the calibration of your tonometer should be checked at least once every month to ensure it performs in accordance with standards and specifications. This leaflet outlines the recommended procedures for checking the calibration of the Haag-Streit AT 900M/Q, AT 900 C/M and AT 900 BQ tonometers. It gives you advice on what to do if you find your tonometer is out of calibration during checks, or if you discover your tonometer is faulty.

Check at measuring drum setting 0 Check position -0.05 Turn the zero calibration on the measuring drum downwards by the width of one calibration marking, against the index marker. When the feeler arm is in the free movement zone, it should then move itself against the stop piece in the direction of the examiner.

Fig. 1: Check position -0.05 Check position +0.05 Turn the zero calibration on the measuring drum upwards by the width of one calibration marking, against the index marker. When the feeler arm is in the free movement zone, it should then move itself against the stop piece in the direction of the patient.

Fig. 2: Check position +0.05

Check at measuring drum setting 2 For this control procedure the check weight is used. Five circles are engraved on the weight bar. The middle one corresponds to drum position 0, the two immediately to the left and right correspond to position 2 and the outer ones to position 6. One of the marks on the weight corresponding to drum position 2 is set precisely on the index mark of the weight holder. Holder and weight are then fitted over the axis of the tonometer (1) so that the longer part of the weight points towards the examiner (Fig. 3).

1

6

2

0

2

Fig. 3: Check weight

CAUTION This is the most important check procedure, as the measuring of the ocular pressure in this area is highly significant.

6

Check at measuring drum setting 2 (cont.) Check position 1.95 When the measuring drum setting is 1.95, the feeler arm should move from the free movement zone against the stop piece towards the examiner.

Fig. 4: Check position 1.95 Check position 2.05 When the measuring drum setting is 2.05, the feeler arm should move from the free movement zone against the stop piece in the direction of the patient.

Fig. 5: Check position 2.05

Check at measuring drum setting 6 Turn the weight bar to scale calibration 6, the longer part shows in the direction of the examiner (Fig. 3). Check position 5.9 The check point is 5.9. The calibration marking 6 on the measuring drum is to be turned 1/2 an interval downwards. The feeler arm should move towards the examiner.

Fig. 6: Check position 5.9

Check position 6.1 The check point is 6.1. The calibration marking 6 on the measuring drum is to be turned 1/2 interval upwards. The feeler arm should move in the direction of the patient.

Fig. 7: Check position 6.1

THE TONOMETER IS FAULTY

What to do if your tonometer shows an error or is faulty

I’ve tested the calibration but my tonometer is showing errors The checks in this leaflet should be completed at east once every month* and a visual inspection should be completed before every use to check for damage. If your tonometer shows errors when you test the calibration, please check the following; The measuring prism is properly inserted The check weight is precisely adjusted The tonometer is on a level surface. Once you have made these checks, repeat the assessment procedure. If the tonometer is still showing errors then the equipment is faulty. Please note, any faulty equipment is not fit for use and requires servicing and calibration. Any faulty tonometry equipment should be returned to the HS-UK Service Division immediately for servicing.

Why choose the HS-UK Service Division? The HS-UK Service Division is the only Haag-Streit authorised tonometer service agent in the UK and, thus, the only organisation that uses genuine HaagStreit tonometer parts and jigs calibrated to HaagStreit standards. Our dedicated tonometer servicing workshop is fully-equipped with state-of-the-art testing equipment which is calibrated to Haag-Streit standards. Our Haag-Streit certified service engineers will service and repair your tonometer quickly, causing minimal disruption to your clinic. *Recommended Haag-Streit guidelines

What does my tonometer service include? Your tonometer contains more than 70 individual parts. For a fixed fee, an HS-UK Service Division Engineer will dismantle your tonometer and check for wear-and-tear or damage to each part. Your tonometer service includes; Replacement cone arm Replacement bearings Tonometer calibration using official Haag-Streit jig Genuine Haag-Streit replacements for any parts which are worn or damaged Correct adjustment in 0, 2 and 6 positions Baseplate and feet check Service report listing parts used and batch numbers Official certificate of calibration to confirm your device has undertaken a full Haag-Streit-approved service procedure A 3-month warranty is also provided, as standard.

Tonometer repair process During the repair process, the HS-UK Service Division will clean the tonometer, ensure movement is smooth, replace any worn parts and check the following; Bottom shaft Shaft spindle, for burrs and damage Shaft bearing bolt wheel & pin Shaft dial bearing Block tension spring Star washer and dial. Middle shaft Shaft pin Block shaft Spindle bar. Top Shaft Spindle and pin Movement of weights. The Engineer will also replace all the top shaft bearings and the cone arm on the tonometer and re-grease the spindle. Once reassembled and calibrated, a certificate will be issued for each tonometer listing the serial number of the tonometer and the serial number of the test jig used for calibration. The HS-UK Service Division maintains compliance with all applicable regulations and standards for the servicing of ophthalmic diagnostic equipment, including certification to BS EN ISO 13485 standards.

Contact us... To book a service or repair For further information, or to book in a tonometer service or repair, please contact the HS-UK Service Division on (01279) 456314 or, alternatively, email [email protected]. Buying a new tonometer If you feel your equipment is not serviceable, or is beyond repair, and you wish to purchase a new tonometer, please telephone 01279 883842, email [email protected] or visit www.haagstreituk.com/goldmanntonometer.

HAAG-STREIT UK Edinburgh Way Harlow Essex CM20 2TT (01279) 456314 [email protected] https://hsuk.co/tonometryservice

E&OE.

5805013/Issue 2/July 2019