US-800 Operators Manual Jan 2009

NIDEK CO., LTD. (Manufacturer) NIDEK CO., LTD (Tokyo Office)

NIDEK INCORPORATED (United States Agent) NIDEK SOCIETE ANONYME (EU Authorized Representative)

: 34-14, Maehama, Hiroishi-cho, Gamagori, Aichi 443-0038, Japan Telephone: 81-533-67-6611 Facsimile: 81-533-67-6610 : 3F Sumitomo Fudosan Hongo Bldg., 3-22-5, Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan Telephone: 81-3-5844-2641 Facsimile: 81-3-5844-2642 : 47651 Westinghouse Drive, Fremont, California 94539, U. S. A. Telephone: 1-510-226-5700 Facsimile: 1-510-226-5750 : Europarc 13, rue Auguste Perret, 94042 CRETEIL, France Telephone: 33-1-49 80 97 97 Facsimile: 33-1-49 80 32 08

January 2009 14800-P902N Printed in JAPAN

BEFORE USE OR MAINTENANCE, READ THIS MANUAL. THIS MANUAL CONTAINS ONLY INFORMATION TO UNDERSTAND THE OPERATING PROCEDURES AND MAINTENANCE. This manual contains information to understand the NIDEK Echoscan Model US-800. This manual contains general information about the device, cautions for safety, operating procedures, and maintenance instructions. This manual is required to correctly use the device. Especially, cautions for safety and operating procedures must be thoroughly understood before using this device. Keep this manual handy to verify use whenever necessary. Use of this device is limited to measurement of the axial length and calculation of the refractive power of an IOL by qualified physicians only. There are no user-serviceable parts inside the device except printer paper and fuses. Therefore, if you find any problems or have questions about the device, please contact your authorized distributor.

Table of Contents

§1 INTRODUCTION ...Page 1-1 1.1 Outline ... 1-1 1.2 Indications for Use ... 1-1 1.3 Principle ... 1-1 1.4 Classifications ... 1-2 1.5 Symbol Information ... 1-3 1.6 Voltage Check ... 1-3

§2 SAFETY PRECAUTIONS ... 2-1

2.1 In Use ... 2-1 2.2 Storage and Transport Environmental Conditions... 2-2 2.3 In Transport ... 2-3 2.4 In Installation ... 2-3 2.5 After Use ... 2-6 2.6 In Maintenance ... 2-6 2.7 In Disposal ... 2-6 2.8 Labels ... 2-7

§3 SYSTEM DESCRIPTION ... 3-1 3.1 Main Body ... 3-1 3.2 Display ... 3-4

§4 OPERATING PROCEDURES ... 4-1

4.1 Preparation ... 4-1 4.2 Axial Length Measurement ... 4-1 4.2.1 Basic operation of axial length measurement ... 4-1 4.2.2 Cautions on measurement ... 4-5 4.2.3 Manual gate ... 4-7 4.3 Check and Setting of the Measured Value and A-mode Waveform ... 4-8 4.4 Calculation of IOL Refractive Power ... 4-11 4.4.1 Calculation... 4-11 4.4.2 Examples of IOL refractive power calculation ... 4-14 4.5 ID Function ... 4-15 4.5.1 Inputting of patient’s data ... 4-15 4.5.2 Delete function ... 4-17

4.6 Other Functions ... 4-18 4.6.1 Registration of IOL data ... 4-18 4.6.2 SF value reverse calculation function ... 4-20 4.6.3 Individual A-constant calculation function ... 4-21 4.6.4 Changing the sonic velocity for conversion ... 4-23 4.6.5 Changing the IOL formula constant ... 4-24 4.6.6 Setting the date and time ... 4-25 4.6.7 Check of the communication function ... 4-26 4.6.8 Printing out ... 4-27 4.7 Using the Test Piece ... 4-28

§5 MAINTENANCE ... 5-1

5.1 Replacement of Printer Paper ... 5-1 5.2 Replacement of Fuses... 5-3 5.3 Cleaning the Exterior ... 5-4 5.4 Selecting the Voltage ... 5-4 5.5 List of Parts for Replacement ... 5-4

§6 IOL FORMULAS ... 6-1

6.1 Outline of IOL Formula ... 6-1 6.2 SRK Formula... 6-1 6.3 SRK-II Formula ... 6-2 6.4 SRK-T Formula ... 6-3 6.5 BINKHORST Formula ... 6-4 6.6 HOLLARDAY Formula ... 6-5

§7 SPECIFICATIONS ... 7-1 §8 ACCESSORIES... 8-1 8.1 Standard Accessories ... 8-1

§9 EMC & ACOUSTICOUTPUT ... 9-1

9.1 EMC (Electromagnetic Compatibility) ... 9-1 9.2 Acoustic output reporting table (IEC 60601-2-37:2005) ... 9-5 9.2.1 A-scan probe... 9-5 9.2.2 Global acoustic output limits ... 9-5

§1 INTRODUCTION 1.1 Outline NIDEK Echoscan Model US-800 is an ultrasonic device to measure axial length which applies the ultrasonic pulse reflection method. It consists of a main unit, solid probes, a foot pedal and a power cord. When touching the probe to the cornea, an ultrasonic pulse is transmitted by a transducer, reflected from each boundary face of intraocular tissue and its echo is received by the same transducer. The US-800 measures the length of various intraocular tissues by measuring the time required for receiving an echo pulse and converting it into distance. The axial length is measured as one of the parameters in order to determine the refractive power of an IOL, when implanting an IOL during in the cataract surgery. In addition, by inputting other parameters, this device can calculate the refractive power of an IOL, which is necessary for the medical treatment.

1.2 Indications for Use NIDEK Echoscan Model US-800 is used for measuring the axial length of the eye. The measured axial length value is used to calculate the IOL power along with other parameters prior to the cataract extraction surgery.

1.3 Principle When voltage is applied to the built-in transducer of a probe, the transducer vibrates and pulsed ultrasonic waves are emitted. The ultrasonic waves have the following properties similar to light in conditions under water or similar media. They have high tendency of traveling straight. They have phenomena such as reflection and refraction on the boundary faces of media which have different acoustic impedances. (Acoustic impedance = Density of medium × Ultrasonic Velocity in the medium) By touching the probe to the eyeball, ultrasonic pulses travels inside the eye. Parts of the pulses are reflected from each boundary face: between the probe tip and the cornea, the cornea and the anterior chamber, the anterior chamber and the lens, the lens and the vitreous, and the vitreous and the retina. Their echoes are received at the same probe from which the ultrasonic pulses are transmitted, which are then shown on the display as electronic acoustic signals. Echo intensity is shown as the height of the waveform. It is possible to calculate the length of different intraocular tissues (axial length, anterior chamber depth, lens thickness and vitreous length) by converting the interval of releasing and receiving each echo into distances. When the directions of the ultrasonic waves are not perpendicular to each tissue boundary face, however, the echo is rather weak or does not return to the probe. For such reason, it is very important to coincide the direction of the ultrasonic waves with the visual axis in order to achieve correct measurement.

1-2

1.4 Classifications [Classification under the provision of 93/42/EEC (MDD)] Class IIa The US-800 is classified as a Class IIa device. [Protection method against electric shock] Class I The US-800 is classified as a Class I device. A Class I is a device in which protection against electric shock does not rely on basic insulation only, but which includes an additional safety precaution in such a way that means are provided for the connection of accessible conductive parts to the protective (earth) conductor in the fixed wiring of the installation in such a way that accessible conductive parts cannot become live in the event of a failure of the basic insulation. [Degree of protection against electric shock] Type B applied part The US-800 is classified as a device with a Type B applied part. A device with a Type B applied part provides an adequate degree of protection against electric shock particularly regarding; -- allowable leakage currents -- reliability of the protective earth connection (if present). [Degree of protection against ingress of liquids] Main body: IP20 An IP20 is an ordinary unit without protection against an ingress of water. Do not expose water to the device. Foot pedal: IPX1 Probe: IPX7 Only the tip of the probe can be soaked in liquid. [Degree of safety of application in the presence of flammable anesthetics and/or flammable cleaning agents] The US-800 should be used in environments where no flammable anesthetics and/or flammable cleaning agents are present. [Mode of operation] Continuous operation [Methods of disinfection recommended by the manufacturer] Disinfect the solid probe tip with the following medical fluid. • 0.1% Chlorhexdine Gluconate Solution • Ethanol for Disinfection

1-3

1.5 Symbol Information This symbol shows that reference to the operator’s manual is necessary for the part before use. This symbol means that the degree of protection against electric shock is for a device with a Type B applied part. This symbol on both sides of the power switch means that the power is ON. This symbol on both sides of the power switch means that the power is OFF. This symbol indicates the fuse rating. Indicates that this product shall be disposed of in a separate collection of electrical and electronic equipment in EU. Indicates that the foot pedal is to be connected to this port. Indicates the connector for the fixation lamp cable of the probe stand.

1.6 Voltage Check The US-800 is equipped with a voltage selector for 100V / 120V / 220V / 240Vac in the fuse holder on the rear panel. Check if the indicated voltage matches the wall outlet.

§2 SAFETY PRECAUTIONS In this manual, Signal Words are used to designate a degree or level of safety alerting, The definitions are as follows. CAUTION: Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury or a property damage accident. To avoid damage to personnel and the delivery unit, follow all of the instructions mentioned below.

2.1 In Use CAUTION • Use this device only for measuring the axial length or calculating the refractive power of an IOL. NIDEK assumes no responsibility for accidents caused by using for other purposes. • In the event of trouble, unplug the power cable and contact your authorized distributor without touching the inside of the device. • Do not modify or touch the inside of the device. Electric shock or malfunction may result. • Use a power outlet with a protective earth ground which meets the requirements of the power specifications, and connect the supplied power cable. If the line voltage is too low or too high, the device cannot deliver full performance and will be damaged. • Never pull the power cable to unplug it from the wall-outlet. Always hold the plug to unplug. The metal core may break and may cause an ignition or electric shock. • Never put weight on the power cable. The cable sheath may break and may cause an ignition or electric shock. • Never pull the probe cable and the foot pedal cable forcefully. The metal cores may break. • Do not use a power cord other than the one supplied. Also do not connect the supplied power cord to any other device. Failure or fire may result. • This device uses a heat-sensitive printer paper. To keep the printed data for a long period of time, make copies of the printouts. The paper degrades over time and the printed data may become illegible.

2-2

CAUTION • If the metal core of cable is exposed, replace it with an undamaged one immediately. It may cause an electric shock or fire. • Be sure to verify that there are no scratches nor chips on the surface of the probe tip. If such a probe is used for measurement, it may damage the patient’s cornea. • Be sure to hold the plug when connecting or disconnecting the probe. The probe cable may be broken if you hold the cable only. • Disinfect the probe tip for every patient. If the probe tip is not disinfected, the cornea may be infected. • Be sure to disinfect the probe tip with medicament. Never autoclave the probe. The probe tip may break.

2.2 Storage and Transport Environmental Conditions CAUTION • Avoid storing the device in places exposed to rain or water, corrosive gas/liquid, or direct sunlight. • Store the device in a stable place that is vibration-free, shock-free, and level. Otherwise the device may fall or malfunction. • Store the device in the following environment: Temperature: -20 to 60ºC (-4 to 140ºF) Humidity: 10 to 95% (Non-condensing) Others: No dust nor corrosive gas/liquid

2-3

2.3 In Transport CAUTION • Never trail the power cable while transporting the device. The device may be damaged if it is bumped, and the power cable may break if it is stepped on or pulled. • Unplug the probe and store it in the attached box before transporting the device. If the probe is hit directly, it may be permanently damaged.

2.4 In Installation CAUTION • Install the device in a level and stable place that is vibration-free and shock-free. The device may fall or malfunction. • Check that the line voltage is proper before plugging the power cable to the power outlet. The proper voltage is shown on the rating plate. If the line voltage is too low or too high, the device cannot deliver full performance and will be damaged. If the line voltage is different from the selected one of the voltage selector, change the voltage of the voltage selector. (See “5.4 Selecting of the Voltage” (P.5-4).) • Avoid installing the device in a place where it is exposed to water. If water gets into the device, electric shock or malfunction may result. • This device has been tested and found to comply with the limits for medical devices to the IEC 60601-1-2:2001, EN60601-1-2:2001, Medical Device Directive 93/42/EEC. These limits are designed to provide reasonable protection against harmful interference in a typical medical installation. This device generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to other devices in the vicinity. However, there is no guarantee that interference will not occur in a particular installation. If this device does cause harmful interference to other devices which can be determined by turning the device off and on, the user is encouraged to try to correct the interference by one or more of the following measures; - Reorient or relocate the receiving device. - Increase the separation between the device. - Connect the device into an outlet on a circuit different from that to which the other device(s) are connected. - Consult the manufacturer or field service technician for help.

2-4

CAUTION • When this device is used together with other equipment, the equipment shall be certified according to Standard IEC60601-1. If this device is used together with equipment which is not certified according to Standard IEC60601-1, you may get an electric shock and the device may have problems. • In installation and operation of the device, observe the following instructions about EMC (electromagnetic compatibility): - Do not use the device simultaneously with other electronic equipment to avoid electromagnetic interference with the operation of the device. - Do not use the device near, on, or under other electronic equipment to avoid electromagnetic interference with the operation of the device. - Do not use the device in the same room with other equipment such as life-support equipment, other equipment that has major affects on the life of the patient and results of treatment, or other measurement or treatment equipment that involves small electric current. - Do not use the device simultaneously with portable and mobile radio frequency communication systems because it may have an adverse effect on operation of the device. - Do not use cables and accessories that are not specified for the device because that may increase the emission of electromagnetic waves from the device or the system and decrease the immunity of the device to electromagnetic disturbance. • The Electromagnetic Compatibility Directive sets the essential requirements for electrical and electronic equipment that may disturb, or be disturbed by, other equipment. The US800 complies with these requirements as tabled on pages 9-1 to 9-3. Follow the guidance in the tables for use of the device in an electromagnetic environment. • Install the device in the following environmental conditions. Temperature: 10 to 40ºC (50 to 104ºF) Humidity: 10 to 85% (Non-condensing) Others: No dust, corrosive gas/liquid nor scattered light

2-5

CAUTION • The patient environment is the volume of space in which contact can occur between the patient and any part of the device (including connected devices) or between the patient and any other person(s) touching the device (including connected devices). Use devices that comply with IEC60601-1 in the patient environment. If any device that does not comply with IEC 60601-1 is to be used, use an isolating transformer or common protective grounding.

Radius of 1.5 m

4#'.%

2.5 m

1.5 m

1.5 m

2-6

2.5 After Use CAUTION • When the device will not be used for a long time, unplug the power cable from the wall-outlet. If dust and moisture settle on the plug of the power cable, a short circuit and a fire may occur. • After using the device, turn OFF the power and put the dust cover on. If the device is not covered for an extended period, the accumulation of dust may allow the device to become insanitary.

2.6 In Maintenance CAUTION • Be sure to use the specified fuses when replacing the fuses. Otherwise the device may malfunction and a fire may occur. • Only a service technician properly trained at NIDEK can repair the device. NIDEK assumes no responsibility for accidents caused by improper repair. • Never use an organic/abrasive solvent to clean the exterior of the device as it may ruin the appearance. • When the device is sent back to NIDEK for repair or maintenance, wipe the surface of the device using a clean cloth dampened with cationic detergent, etc. (such as Benzalkonium chloride: 0.05 - 0.2% solution) which does not cause deformation or discoloration of the surface.

2.7 In Disposal CAUTION • Follow local governing ordinances and recycling plans regarding disposal or recycling of device components when disposing of the device. Especially the disposal method of lithium batteries varies according to the government. This device has electric circuit boards with lithium batteries. When disposing of the boards, follow the instructions of the government. • When disposing of packing, sort it by material and follow local governing ordinances and recycling plans.

2-7

2.8 Labels In order to draw the operator’s attention, the appropriate warning labels are attached to the specified locations on the rear panel of the device.

(4#)+.' (4#)+.'

+2:

+2:

§3 SYSTEM DESCRIPTION 3.1 Main Body [Top view]

[Front view]

3-2 Display The display shows the data, A-mode waveforms, etc.. F keys [ , , , ] These keys are used to operate and to set the functions in the designated mode. The functions of these keys are shown on the display. Mode keys [ , , , , ] These keys are used to set the modes: Measuring mode, LIST mode, IOL mode, ID mode, and Function menu. • key This key is used to set the measuring mode. • key This key is used to set the LIST mode which shows the measured data list. • key This key is used to set the IOL mode for calculating the refractive power of an IOL. • key This key is used to set the ID mode in which the patient’s data is inputted. • key This key is used to set the mode of the Function menu. Alphanumeric keys These keys are used to input the patient’s data and IOL data. Arrow keys [ , , , ] These keys are used to move the manual gate, to set the items, and to set the time and date. key This key is used to set inputted figures and letters.

key This key is used to correct inputted figures and letters. By pressing this key, one letter to the left of cursor is deleted. Numeric keys These keys are used to input numbers. key This key is used in the measuring mode to changeover the freeze condition to the measuring condition alternately instead of the pedal. key This key is used to feed the printer paper. key This key is used to print out data on the display. Printer cover This cover is opened and closed when changing the printer paper. Probe rest This is used to place the probe on when it is not in use. Contrast control [CONTRAST] This is used to control the contrast on the display. Adjust the contrast for clear vision. Sensitivity control [GAIN] This is used to adjust the sensitivity as [GAIN] of the echo. By turning it clockwise, the sensitivity increases. Pilot lamp [POWER] This lights up while the power is ON. Probe connector [PROBE] The solid probe for axial length measurement is connected to this plug.

3-3 [Rear View]

External interface [RS-232C] External personal computers can be connected through this interface. Accessory equipment connected to the analog and digital interfaces must be certified according to the representative appropriate national standards (for example, UL 1950 for Data Processing Equipment UL 60601-1 for Medical Equipment, and CSA C22.2 No. 601-1, EN 60601-1 and IEC 60601-1.) Furthermore all configurations shall comply with the system standard IEC 606011-1. Anyone who connects additional equipment to the signal output part configures a medical system, and is therefore responsible that the system complies with the requirements of the system standard IEC 60601-1-1. If in doubt, consult the technical service department or your local representative.

Adjuster leg By turning this adjuster leg, you can adjust the inclination of the device to get a clear vision of the display. Fuse holder It contains the voltage selector as well as implanted fuses. Power cord inlet [INLET] Power switch [POWER] Pedal plug [FOOT SW.] The cable of the foot pedal is connected to this plug. Fixation light plug [FIX. LIGHT] This plug is for the fixation light.

3-4

3.2 Display This chapter explains words and abbreviations indicated on the display and printouts. A. Measuring mode This mode is for measuring axial length.

Conditions [>FREEZE</>START<] >FREEZE< is displayed while in the frozen condition and >START< is displayed while measuring. Measurement [AUTO1/AUTO2/AUTO3/MANU] It shows whether the measurement is automatic or manual. Use the key to set AUTO1, AUTO2, AUTO3 or MANU. In auto measurement, A-mode waveforms are automatically judged.* When it is good, measured data will be shown on the display and frozen automatically. In manual measurement, measurement is continued without freezing though measured data is shown on the display. When a good A-mode waveform is obtained, step on the foot pedal or press key to freeze it.

…

Manual gate [GTOFF/GTON] It shows whether the manual gate function is on or off. The position of the gate is indicated with a dotted line ( ) in the A-mode waveform. Use the key to set the ON/OFF of the manual gate. Condition of a patient’s eye [PHAKIC/APHAKIC/IOL] It shows the condition of a patient’s eye. Set PHAKIC for a phakic eye, APHAKIC for aphakic eye, and IOL for an IOL implanted eye. Use the key to set the condition of a patient’s eye.

* For details, see page 4-2.

3-5 OD/R or OS/L display This shows whether the eye to be measured is the right eye (OD/R) or left eye (OS/L). Use the key to set OD/R or OS/L. OD/R: Oculus Dexter/Right eye OS/L : Oculus Sinister/Left eye Axial length This shows the measured axial length in mm. Sonic velocity for conversion This is the sonic velocity used in calculating axial length. Anterior chamber depth [AD] This shows the measured anterior chamber depth in mm. Lens thickness [LT] This shows the measured lens thickness in mm. Vitreous body length [VT] This shows the measured vitreous body length in mm. Average [AV] This shows the average of the measured axial lengths. Standard deviation [SD] This shows the standard deviation of the measured axial length. A-mode waveform This shows the condition of the echo received by the probe. The vertical lines show the intensity of the echo, and the horizontal lines show the time that the echo takes to travel through the several tissues of the eye. Scale This scale is a standard guideline of A-mode waveform when the converting sonic velocity is set at 1550m/s and the horizontal line is converted to the distance. One graduation corresponds to 5mm.

3-6 B. LIST mode This mode is to check the measured values and A-mode waveform and to set the measured value which is used for calculating IOL refractive value.

Axial length [L] This shows the last six values of axial length including the latest value. (Column 1) Average [AV] This shows the average of the measured axial lengths. Standard deviation [SD] This shows the standard deviation of the measured axial lengths. A-mode waveform This shows the A-mode waveform of the value where the cursor ( ) points. OD/R or OS/L display [OD/R or OS/L] It shows that displayed data is either for the right eye (OD/R) or left eye (OS/L). Use the key to set this item.

3-7 C. IOL mode In this mode, IOL refractive power is calculated.

IOL formula [SRK/SRK-2/SRK-T/BINKHORST/HOLLARDAY] This shows the IOL formula for calculation. Use the key to set the IOL formula. IOL type This shows the IOL type used for calculating IOL refractive power. Use the this item.

key to set

OD/R or OS/L display [OD/R or OS/L] This shows the right eye (OD/R) or left eye (OS/L) from which IOL refractive power is calculated. Use the key set to OD/R or OS/L.

3-8 Corneal curvature [K-1, K-2] These are the lines to input the data of corneal curvature, which is one of the parameters for IOL refractive power calculation. The data can be input in either mm (Corneal radius) or D (Corneal refractive power). *Corneal refractive power (D) = 337.5/Corneal radius (mm) A-constant [A] This is the line to input the A-constant of an IOL which is one of the parameters for IOL refractive power calculation. Predicted pose operative anterior chamber depth [AD] This is the line to input the predicted post operative anterior chamber depth, which is one of the parameters for IOL refractive power calculation. Surgeon factor [SF] This is the line to input the surgeon factor which is one of the parameters for IOL refractive power calculation. Desired postoperative refractive power [TGT] This is the line to input the desired post operative refractive power which is one of the parameters for IOL refractive power calculation. Axial length [AXL] This is the line of axial length which is to be used for designated calculation in LIST mode. Ametropic IOL refractive power [IOL] This shows the calculated ametropic IOL refractive power. Spectacle refractive power for aphakic correction [SPE.] This shows the calculated spectacle refractive power for aphakic correction.

Contact lens refractive power for aphakic correction [C.L.] This shows the calculated contact lens refractive power for aphakic correction. IOL refractive powers in diopters [IOLP] This column shows the refractive power of IOL’s which would be closest to the value displayed for the calculated IOL. “>” shows the closest value to the calculated ametropic IOL refractive power. Predicted postoperative refractive power [ERROR] The predicted postoperative refractive power in the case that the IOL of the power which is displayed at [IOLP] is implanted.

§4 OPERATING PROCEDURES 4.1 Preparation 1. Plug the power cord into a wall outlet. 2. Connect the cable of the foot pedal to the pedal plug [FOOT SW.] of the rear panel. 3. Connect the cable of the solid probe to the probe connector [PROBE]. Insert the connector with its red mark up.

4.2 Axial Length Measurement 4.2.1 Basic operation of axial length measurement 1. Turn the power switch [POWER] ON. Pressing the | side of the power switch of the rear panel will turn the device ON and the POWER ON display will appear. Pressing the { side of the power switch will turn the device OFF.

2. Press the

key.

It becomes the measuring mode. This key is also available to enter this measuring mode from other modes .

NOTE • Check the measurement and measured values by using the test piece before measuring the patient’s cornea. (See “4.7 Using the Test Piece” (P.4-28). )

4-2 3. By pressing the

key, select the measurement mode.

The measurement mode changes in the following order for every pressing of the key.

AUTO1 / AUTO2 / AUTO3 / MANU

• Auto measurement 1 (AUTO1) After the A-mode waveform is judged, the measured data will be frozen automatically. • Auto measurement 2 (AUTO2) AUTO2 calculates the difference of two consecutive measured values, in addition to the judgement of A-mode waveform. When the difference is little, the measured data becomes frozen automatically. • Auto measurement 3 (AUTO3) In order to freeze consistent values, AUTO3 calculates the differences of three consecutive measured values, in addition to the judgement of A-mode waveform. When the differences are little, the measured data becomes frozen automatically. • Manual measurement (MANU) Measuring will be continued without freezing though measured data is shown on the display. When good A-mode waveform is obtained, press the foot pedal or key to freeze it. AUTO2 and AUTO3 prevent measured data affected by movement of the eyeball and/or probe from being frozen. Select the LTD mode in AUTO2 or AUTO3, and more consistent measured data can be memorized. When the device is not in the LTD mode, any measured value which is obtained is memorized regardless of whether the display is frozen or not. Press the key to select the LTD mode, and “LTD”(=Limited) appears in the lower section of the axial length value. In this LTD mode, only when the display is frozen automatically, measured data are memorized as follows. The LTD mode works only when the measurement mode setting is AUTO2 or AUTO3.

4-3 • LTD mode in AUTO2 When the display is frozen automatically, the two consecutive measured values which are used to judge the stability of measured value are memorized. • LTD mode in AUTO3 When the display is frozen automatically, the three consecutive measured values which are used to judge the stability of measured values are memorized. Press the

key again, and the device returns to the normal condition.

The setting for measurement mode and LTD mode will remain even if the power is turned OFF. 4. By pressing the

key, select the condition of the patient’s eye.

The Patient’s eye condition changes in the following order for every pressing of the key.

5. By pressing the

PHAKIC / APHAKIC / IOL

key, select right or left for the patient’s eye.

The right eye (OD/R) and left eye (OS/L) appear alternately for every pressing of the key. OD/R : Oculus Dexter/Right eye OS/L : Oculus Sinister/Left eye

6. Press the foot pedal or

key.

Axial length measurement starts.

OD/R or OS/L

4-4 7. Put the probe to the center of the patient’s cornea. A-mode waveform and measured values appear on the display. In auto measurement (AUTO1, AUTO2, AUTO3), measured data and the A-mode waveform are judged, and when good measured values are obtained, they are frozen freezes automatically. Beep sounds give notice that data is frozen and the measurement is finished. In manual measurement, freeze the data as soon as you recognize a good A-mode waveform by pressing the foot pedal or key. Data become frozen and the measuring will be finished. To start measurement again, press the foot pedal or key again. Measurement starts.

NOTE • When measuring an aphakic eye, anterior chamber depth (AD) and lens thickness (LT) are not measured. When measuring an IOL implanted eye, lens thickness (LT) is not measured. The distance between the cornea and the anterior surface of an IOL is measured as anterior chamber depth (AD). • Auto measurement (AUTO1, AUTO2, AUTO3) is just function to make the operation easier and is not appropriate for clinical judgement. It is essential for the operator to check the measured data before using the data for IOL refractive power calculation. • The sonic velocity for conversion in axial length measurement is as follows. Phakic eye : 1550m/s (Axial length) : 1532m/s (Anterior chamber and Vitreous body) : 1641m/s (Lens) Aphakic eye : 1532m/s (Axial length) IOL implanted eye : 1554m/s (Axial length) * If you want to change the sonic velocities for conversion to other than the above, see “4.6.4 Change of sonic velocity for conversion”(P.4-23). * The sonic velocity for conversion is indicated to the left of measured data.

4-5

4.2.2 Cautions on measurement

20 mm

(1) Disinfect the probe tip for every patient using the following method, and verify that there are no scratches nor chips on the surface of the probe tip. Soak the probe tip (max. 20mm) for 10 minutes.

The medical fluids are: 1. 0.1% Chlorhexdine Gluconate Solution 2. Ethanol for Disinfection (2) After disinfection, wipe the probe tip with the disinfected absorbent cotton containing ethanol, and dry the probe tip before using. (3) Instruct the patient not to move his/her eyes. (When the patient is straining, instruct him/her to relax.) (4) Make sure that the probe is in contact with the cornea at the center without applanation. The contact condition on the cornea is a very important factor to obtain a correct value. Find the best position to obtain the best A-mode waveform by changing the probe contact angle. An A-mode waveform in good condition means that it has echoes from 3 places: the cornea, the anterior and posterior surfaces of a crystalline lens, and a large retina echo which rises sharply and is accompanied by a small sclera echo on the A-mode waveform display. Decrease the sensitivity by turning the GAIN control counterclockwise.

Make sure of the following items before freezing the measured value. (a) Is a good A-mode waveform obtained? (b) Is the probe in contact with the cornea properly? (c) Is the patient’s eye fixed? (d) Are the measured values stabilized? (Is the tolerance of measured values within ±0.05mm?) * If you try to measure quickly, correct values cannot be obtained. Be calm and take time to measure.

4-6 (6) In AUTO1/AUTO2/AUTO3 measurement, if the display does not freeze though measured values are shown, the reason may be that the retinal echo does not stand well, or the lens echo is too small (at PHAKIC measurement). Referring to the A-mode waveform on the display, change the condition of the probe contact on the cornea or the angle of the probe and measure again.

Good A-mode waveform

Corneal echo

Retinal echo

Anterior echo Posterior echo

Bad A-mode waveform

Scleral echo

4-7

4.2.3 Manual gate This is used when there is an extra large echo in front of the actual retinal echo. (Including the case when there are multiple echoes of an IOL when the implanted eye is measured.) 1. Press the

key to turn the manual gate function ON.

The display of “GTOFF” changes to “GTON” and the detection gate (dotted line on the A-mode wave form) appears on the display.

2. Press on arrow key or to adjust the detection gate to the position where you desire to put the manual gate. Pressing an arrow key or simultaneously with the key makes the cursor move continuously.

Detection gate

Position the detection gate just to the left of the rising point of the true retina echo. Any echoes to the left of the detection gate are not regarded as the retinal echo.

[Cautions in using the manual gate] 1) When the manual gate is moved in the frozen condition, the measured value does not change simultaneously. Release the frozen condition once and measure again so that the data using the manual gate will be obtained. 2) By pressing the

key again, the manual gate function can be released.

4-8

4.3 Check and Setting of the Measured Value and A-mode Waveform (a) This device can memorize the last 6 measured sets of data and A-mode waveforms. It is available for you to check the measured data and A-mode waveform in the LIST mode. 1. Press the

key.

The display changes to the LIST mode.

2. Press the numeric key of the desired number of the measured value for checking the A-mode waveform.

Cursor

The cursor ( ) will move and the A-mode waveform will change to the corresponding number.

NOTE • The cursor ( ) shows the No. of the measured value of which the A-mode waveform is shown on the display. • The lowest number shows the latest frozen data.

Anterior chamber depth Axial length

Vitreous length

Lens thickness

key to check anterior Press the chamber depth, lens thickness, and vitreous length.

The measured data No. of the A-mode waveform is displayed.

Press the key to magnify the A-mode waveform for checking. The A-mode waveform will be enlarged double in horizontal direction.

4-9 (b) Operate as follows to set the measured data which is used for the calculation of IOL refractive power. 1. In the LIST mode, press the numeric key ( ) of the measured data No. which is used for calculating. No.7 shows the average value of No.1 No.6.

2. Press the

key.

“>” mark is indicated at the selected number.

NOTE • The measured value of the number with the “>” mark is used for the calculation of IOL refractive power. (This value is automatically input at IOL refractive power calculation.) The “>” mark is usually indicated at No.1, so the latest measured value is used for calculating unless it is changed in the above steps. • The measured value No.1 in which the value of L (Axial Length) is 0.00 cannot be used for IOL refractive power calculation. • If you set No.7, the average (AV) of the measured values of Nos.1 - 6 will be used for IOL refractive power calculation.

4 - 10 (c) When using the average measured value (No.7) for IOL refractive power calculation, a measured value which varies widely can be erased with the edit function to decrease the standard deviation [SD]. 1. Press the number key ( ) of the measured value to be erased. The cursor ( ) will move and the A-mode waveform changes to the one of the corresponding numbers.

2. Press the

key.

The line of the selected measured value will disappear and the next line moves up. The average and standard deviation will be calculated again and indicated on the display.