Nidek Medical ARK-500A User manual

AUTO REF/KERATOMETER
Model ARK-500A
OPERATOR’S MANUAL

3
BEFORE USE: Configuration
1
1.4 Configuration
{Front view
Function buttons
Set the device and switch the screen.
Functions assigned to the function buttons are displayed by icons on the screen.
Two buttons on the left of the screen have unique functions when the measurement screen is displayed.
• Clear button ( )
Erases the measured data.
When the clear button is pressed for about a second, all the measured data is erased.
Function buttons
LCD
Memory indicator
Start button
Joystick
Locking lever
Power switch
Printer cover
Cover open button

4
BEFORE USE: Configuration
• Print button ( )
Pressing this button when the memory indicator is lit, prints out the measured data.
Pressing the button when the memory indicator is not lit, advances printer paper.
LCD
5.7-inch LCD. Pulling the bottom of the display panel provides an
adjustable viewing angle.
For measurement in a standing posture, set the panel at a suitable
angle. The panel is reset to its original position by magnet.
Memory indicator
Indicates that measured data is being saved in memory.
Start button
When the start button is pressed, measurement is taken regardless
of the alignment or focusing condition of the device.
Joystick
Used for alignment and focusing.
Alignment in the side-to-side direction can be performed by moving the joystick to the right and left. Rotating the
joystick is for alignment in the up-and-down direction. For focusing, move the joystick back and forth.
Locking lever
Secures the main body to the base.
To lock the main body, press the locking lever down.
Power switch
Turns on the power to the device.
Printer cover
Inside is the printer equipped with the auto cutter located. Open the printer cover for replacing printer paper
by pressing the cover open button.
Cover open button
To open the printer cover, press the button.
ON Being saved
OFF Not being saved
Blink Sleep mode

5
BEFORE USE: Configuration
1
{Rear view
Forehead rest
During measurement, the patient’s forehead should be gently rest against the forehead rest.
Clean the chinrest for each patient.
Measuring window
Check the window cleanliness before measurement.
Chinrest
Clean the chinrest for each patient.
Eye level marker
Used as a guide for the patient’s eye level during measurement.
The height of the chinrest should be adjusted so that the center level of the patient’s eye almost aligns with this line.
Chinrest up/down buttons ( , )
Move up or down the chinrest.
PD window
An LED is provided to detect the PD value.
Eye level marker
Chinrest up/down buttons
PD window
Forehead rest
Measuring window
Chinrest
• Parts that come into contact with the patient during measurement are composed of the
following materials.
Forehead rest: Elastomer
Chinrest: ABS resin

6
BEFORE USE: Configuration
{Bottom view
Power inlet
Connect a detachable power cord.
RS-232C ports
Connect a communication cable to send/receive the measured data to/from a diagnostic device or such.
Target device
RT-1200 series, RT-2100 series, RT-5100
LM-500, LM-970, LM-990/990A, LM-1000/1000P, LM-1200
Connecting the lensmeter to the side and the RT-2100/RT-5100 to the side allows data transmission to
the connected refractor via the ARK-500A.
USB-A port
Connect the optional barcode scanner.
Do not connect equipment other than the barcode scanner.
*1 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 Equip-
ment, and CSA C22.2 No. 601-1, EN 60601-1, and IEC 60601-1.) Furthermore, all configurations shall comply with the
system standard IEC 60601-1-1. Anyone who connects additional equipment to the signal input part or 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.
USB-A port
Power inlet
RS-232C ports
(OUT)
To export the measured data to the refractor (RT), an external computer or such,
connect a communication cable to this side.
The optional Eye Care card system is connected to this side.
(IN) To import the measured data to from a NIDEK lensmeter, connect a communication
cable to a lensmeter.

7
BEFORE USE: Measurement Screen Layout
1
1.5 Measurement Screen Layout
The screen for AR (refractive error) and KM (corneal curvature radius) measurements is comprised of
pages 1 to 3.
Each page differs only in the touch icons displayed to the right of the screen.
<When Page 1 is displayed>
Patient’s eye
Indicates the right or left eye of the patient.
R/K button ( )
Selects a measurement mode in R/K measurement.
Select from AR/KM measurement mode, AR measurement mode or KM measurement mode. The selected
measurement mode is displayed on the screen.
The measurement mode switches in the following order: AR/KM measurement mode (successive AR and KM
measurements) →AR measurement mode (AR measurement)→KM measurement mode (KM measurement)→
AR/KM measurement mode......
Target
Used as a guide to locate the patient’s eye in the center of the screen. Align the mire ring projected on the
patient’s eye with the target.
Auto button ( )
Selects the auto-tracking function and auto-shooting function.
Select auto-tracking from (UpDown) or OFF. Select auto-shooting from ON or OFF.
Patient’s eye
R/K button
Target
Auto button
Minimum pupil circle
Measured values
CYL mode
CS/PS/PD button
Focusing indicator
Manual mode button
Ring image enlarge-
ment button
Mire ring
Page button
Auto-tracking indication
Auto-shooting indication

10
BEFORE USE: Measurement Screen Layout
<When Page 2 is displayed>
* CS, PS, and PD data, ID indication, Eye Care card and cataract measurement mode indication
are displayed on each page.
CAT measurement mode indication ( )
Indicates that the eye has been measured in cataract measurement mode.
If cataract or abnormal eyes cannot be measured, cataract measurement mode is automatically turned on.
See “2.3.1 Cataract measurement mode” (page 37) for details on cataract measurement mode.
PS (Pupil Size) indication
Displayed when PS (Pupil Size) is measured. (increments: 0.1 mm)
CS (Corneal Size) indication
Displayed when CS (Corneal Size) is measured. (increments: 0.1 mm)
ID indication ( )
Displayed when the patient ID is entered.
Enter the patient ID using the optional barcode scanner.
CYL mode button ( )
Switches cylinder mode, the reading direction of cylinder data in which CYL data is represented.
Cylinder mode can be switched even after measurement.
Data is printed out with the mode status at the time of printing.
CAT measurement mode in-
dication
PS (Pupil Size) indication
CS (Corneal Size) indication
ID indication
PD (Pupillary Distance) indication
CYL mode button
Eyeprint button
CYL- Indicates the cylindrical power by - reading.
CYL+ Indicates the cylindrical power by + reading.
CYL±
Cylinder data is indicated by + reading when the refractive error is positive for any axis
angle.
Indicates the cylindrical power by - reading in other cases.

13
BEFORE USE: Labels
1
1.6 Labels
Cautionary labels are provided on the device.
If labels are curling up or characters fading and becoming barely legible, contact NIDEK or your autho-
rized distributor.
Indicates that caution must be taken. Refer to the operator’s manual before use.
Indicates a Type B applied part as a degree of protection against electric shock for applied parts.
Indicates that the state of the power switch. When the symbol side of the switch is pressed
down, power is not supplied to the device.
Indicates that the state of the power switch. When the symbol side of the switch is pressed
down, power is supplied to the device.
Indicates that the device must be supplied only with alternating current.
Indicates the input part.
Indicates the output part.
Indicates the date of manufacture.
Indicates the manufacturer.
Indicates that this product shall be disposed of in a separate collection of electrical and
electronic equipment in EU.

14
BEFORE USE: Checking Contents
1.7 Checking Contents
Unpack the contents from the shipping carton and check them.
The following are included in the standard configuration.
[Bottom side]
• Main body
• Printer paper (3 rolls)
• Power cord
• Dust cover
• Pack of chinrest paper
• Fixing pins for chinrest paper (2 units)
• Operator’s manual (this book)
• Model eye for R/K measurement/Contact Lens (CL) holder (integral type)

15
BEFORE USE: Before First Use
1
1.8 Before First Use
Place the device on a stable table and connect a power cord to it.
1 Place the main body on a stable table.
2Pull the main body fully to the side on which
the device is laid down, lock the main body to
the base unit with the locking lever and lay the
device down gently.
3Connect the power cord to the power inlet.
4Connect peripheral devices if necessary.
See “3 OPERATION WHEN PERIPHERAL DEVICES ARE CONNECTED” (page 77) for the
method of connecting peripheral devices.
5Stand the device upright.
6Confirm that the power switch is turned OFF
( ) and plug the power cord into a wall out-
let.
Power inlet
Power switch
CAUTION
• Be sure to use an outlet equipped with a ground terminal.
Electric shock or fire may occur in the event of device malfunction or power leakage.

16
BEFORE USE: Before First Use
7Turn ON ( ) the power switch.
The initial screen is displayed on the LCD and
the device starts initializing.
8Confirm that the measurement screen is dis-
played.
9Set the printer paper.
See “4.3 Replacing Printer Paper” (page 92) for details on the setting method.
This completes setup procedure.
Initial screen
Measurement screen
• When the device is used for the first time, “NO PAPER” appears indicating that no paper is
loaded.
• Set the parameters as necessary or desired.
See “2.12 Parameter Settings” (page 60) for the parameters and their setting methods.
• See “3 OPERATION WHEN PERIPHERAL DEVICES ARE CONNECTED” (page 77) for the
method of connecting peripheral devices.

20
OPERATING PROCEDURES: Preparation for Measurement
2.2 Preparation for Measurement
1Turn the power switch on ( ).
The title screen is displayed and the device is ini-
tialized.
Wait for a while until the screen switches to the
measurement screen.
• When the WINDOW CHECK parameter is
set to ON, the MEASURING WINDOW
CHECKING screen is displayed before the
measurement screen is displayed.
See “2.2.1 Checking the measuring window
cleanliness at device start-up” (page 26) for
details.
Power switch
Initial screen
MEASURING WINDOW CHECKING screen

21
OPERATING PROCEDURES: Preparation for Measurement
2
2The measurement screen is displayed.
3Perform checks before use.
Perform the following checks before use.
No error message appears.
The main body moves smoothly using the joystick.
The chinrest moves up and down by pressing the chinrest up/down button.
Printer supply is adequate.
The AR/KM measurement accuracy satisfies the specifications.
See “4.5 Checking the AR/KM Measurement Accuracy” (page 95) for details.
Follow “4.1 Troubleshooting” (page 87) if abnormal conditions are encountered.
4Establish the measurement conditions.
The following conditions should be specified:
1 : Measurement mode
Press the R/K button to select.
When the power is turned on, a mode in which the power was turned off is established.
The measurement items corresponding to the selected measurement mode are displayed
on the screen.
• If the power is turned on with no paper loaded, the error message “NO PAPER” appears.
Supply printer paper.
Measurement mode Description
AR/KM measurement
mode
AR (refractive error) and KM (corneal curvature radius) measurements are
successively taken.
AR measurement
mode Only AR (refractive error) measurement takes place.
KM measurement
mode Only KM (corneal curvature radius) measurement takes place.
Measurement screen

22
OPERATING PROCEDURES: Preparation for Measurement
Pressing the button switches the measurement mode in the following order: AR/KM→AR→
KM→AR/KM→......
2 : Auto-tracking function and auto-shooting function
Specify the alignment (up-and-down directions) methods and the method of triggering measure-
ments.
Press the auto button to select the auto-tracking and/or auto-shooting function.
3 : Parameter-set measurement conditions:
The ARK-500A is equipped with a function to change parameters of various device conditions
according to the operator’s needs.
See “2.12 Parameter Settings” (page 60) for details.
4 : CYL mode
Cylinder mode, the reading direction of cylinder data in which CYL data (cylindrical power) is repre-
sented during the measurement is selected by pressing the CYL mode button .
Auto-tracking
Auto-
shooting
Screen
display Description
Up-and-
down
ON
Auto-tracking in the up-and-down direction is turned on.
Manually align the device in the side-to-side direction.
Measurement starts automatically when the eye is focused.
OFF
Auto-tracking in the up-and-down direction is turned on.
Manually align the device in the side-to-side direction.
Bring the eye into focus and press the start button to start
measurement.
OFF
ON
Manually align the device and bring the eye into focus.
Measurement starts automatically when the eye is best aligned
and focused.
OFF (No
indication)
Manually align the device and bring the eye into focus.
Press the start button to start measurement.
• The functions assigned to the auto button varies according to the 62. TRACKING
SW parameter setting.
See “2.12 Parameter Settings” (page 60) for the setting procedure.
Screen
display CYL mode Description
CYL- - reading Indicates the cylindrical power by + reading.
CYL+ + reading Indicates the cylindrical power by - reading.
CYL± Mix reading
Indicates the cylindrical power by + reading when the refractive
error is positive for any axis angle.
Indicates the cylindrical power by - reading in other cases.
AR/KM measurement mode AR measurement mode KM measurement mode

23
OPERATING PROCEDURES: Preparation for Measurement
2
5Prepare the patient.
1) As necessary, enter the patient ID using a barcode scanner.*1
The optional barcode scanner is needed.
See “3.4 Reading Patient IDs” (page 84) for the method of entering patient IDs.
2) Wipe the forehead rest and chinrest that con-
tact the patient with clean absorbent cotton or
gauze dampened with rubbing alcohol.
If a stack of chinrest paper is fixed on the chinrest,
remove one sheet of paper.
3) Instruct the patient to take off glasses or con-
tact lenses and sit on a chair.
4) Have the patient place his/her chin on the chinrest as deeply as possible, and his/her
forehead on the forehead rest lightly.
• Cylinder mode can be changed even after measurement.
• All saved data is printed out along with the mode status.
• These settings are retained even after shutdown of the device; Change these
measurement conditions only if necessary.
*1. Patient IDs may be read at any time prior to printing.
• To reassure the patient, before measurement, explain as follows.
“This device measures your eye with infrared ray to find which kind of lens fits you. The infrared ray does
no harm to your eyes.”
Forehead rest
Chinrest

24
OPERATING PROCEDURES: Preparation for Measurement
5) Adjust the height of the chinrest by the chin-
rest up/down button ( , ) until the cen-
ter level of the patient’s eye aligns with the
eye level marker.
Before adjusting the height of the chinrest, let the
patient know that the chinrest moves up and down.
When the chinrest is at the upper (or lower)
mechanical limit, the upper limit indication (or
lower limit indication ) is displayed on the
screen.
6Start measurement.
For details of each measurement, see:
“2.3 AR (refractive error) and KM (corneal curvature radius) Measurements: AR/KM Measurement
Mode” (page 29)
“2.4 AR (refractive error) Measurement: AR Measurement Mode” (page 39)
“2.5 KM (corneal curvature radius) Measurement: KM Measurement Mode” (page 41)
• When the ARK-500A displays a thumbnail, the limit indication ( , ) is covered and
cannot be seen.
• Instruct the patient not to blink during measurement. Additionally, instruct the patient not to
blink and open his/her eyes immediately before measurement to avoid measurement
failure.
• Instruct the patient to open both eyes wide during measurement.
Closing one eye may cause an unstable fixation and the other eye will not open wide.
Eye level marker
Limit indication

27
OPERATING PROCEDURES: Preparation for Measurement
2
2.2.2 Switching to manual mode
It is possible to turn off both the auto-tracking and auto-shooting functions (manual mode) by pressing
the manual mode button during measurement.
The manual mode button is used to turn off the auto-tracking function according to the patient’s eye
after starting measurement with the auto-tracking function on. (The manual mode button functions
even when only the auto-shooting function is turned on.)
Allowing the operator to turn off both the auto-tracking and auto-shooting functions with a single
button. It saves the operator the trouble of pressing the auto button repeatedly.
1 Press the manual mode button during mea-
surement.
The auto-tracking indication and auto-shooting
indication become blank ( ), indicating
that these functions are turned off.
2Manually align the main body to the eye and bring the eye into focus.
3Press the start button to start measurement.
One of the following operations returns to the state before the manual mode button was pressed.
• Pressing the manual mode button again.
• Switching the eye to be measured between the right and left eyes.
• Pressing the clear button .
• Press the print button .
• For eyes with a small pupil and with the corneal vertex shifted from the pupil center, if the
auto-tracking function is turned on and the pupil overlaps the minimum pupil circle, the eye
may not be measured.
To measure such eyes, turn off the auto-tracking function and align the minimum pupil circle with the
pupil.

28
OPERATING PROCEDURES: Preparation for Measurement
2.2.3 Sleep mode
The device goes into sleep mode automatically to save power if no button have been pressed for a
certain period of time.
The time that the device goes into sleep mode can be selected from 5 minutes, 10 minutes,
15 minutes, or NO (no sleep mode) (factory setting: 5 minutes).
Sleep mode places the device into the following condi-
tions:
• The LCD goes off.
• The memory indicator blinks.
The device recovers to normal mode from sleep mode by
the following methods:
• Press any button.
• Manipulate the joystick to move the base R or L.
2.2.4 Finishing the measurement
1 To finish the measurement, turn off ( ) the power switch.
It is allowed to turn off the power with any screen displayed.
2Check the measuring window and clean the lens if necessary.
See “4.6 Cleaning” (page 97).
3Clean the forehead rest and chinrest, and put the supplied dust cover on the device.
Always keep them clean for the next use.
• Depending on the status of the LCD, the device may not go into sleep mode.
When the PARAMETER SETTING screen is displayed, the device does not go into sleep mode.
• Be sure to put the dust cover on whenever the device is not in use.
Memory indicator

29
OPERATING PROCEDURES: AR (refractive error) and KM (corneal curvature radius) Measurements: AR/KM
2
2.3 AR (refractive error) and KM (corneal curvature radius)
Measurements: AR/KM Measurement Mode
In AR/KM measurement mode, AR measurement and KM measurements are successively taken.
When AR/KM measurement mode is selected, refractive errors (S, C and A) and corneal curvature
radius (R1, R2) are displayed on the screen.
1 Instruct the patient to: “Look through the measur-
ing window. As you will see the picture of a bal-
loon, watch the center of it without straining”.
• When the 12. KM DISPLAY parameter is set
to AVE, CYL, the indications on the
measurement screen are as shown on the
right.
AVE: Average of R1 and R2
CYL: Corneal cylindrical power & Corneal cylinder
axis angle
R: AR measurement count
S: Spherical power
C: Cylindrical power
A: Cylinder axis angle
K: KM measurement count
R1: Corneal curvature radius and corneal cylinder axis
angle of flattest meridian
R2: Corneal curvature radius and corneal cylinder axis
angle of steepest meridian
Scenery chart

30
OPERATING PROCEDURES: AR (refractive error) and KM (corneal curvature radius) Measurements: AR/KM Measurement Mode
2Manipulate the joystick to display the patient’s
eye on the screen.
By moving the joystick laterally, the main
body moves right, left, back and forth. By
turning the upper part of the joystick, the main
body moves up and down.
Align the eye position to the measuring point
with right, left, up and down movements.
Adjust the focus with back and forth move-
ments.
3Perform alignment and focusing.
The methods of alignment and focusing vary
according to the 26. TRACKING SW parameter
setting.
* See “2.2 Preparation for Measurement” (page 20) for
details.
Perform alignment by placing the mire ring
reflected by the patient’s eye in the center of the
target.
Perform focusing according to the indication of
the focusing indicator displayed on the screen.
Up-and-down auto-tracking
1) Perform rough alignment and focusing by
manipulating the joystick to place in the
working range of auto-tracking.
2) When the device is placed within the
working range of auto-tracking, it automat-
ically starts alignment in the up-and-down
direction.
3) Manipulate the joystick to move the mire
ring reflected on the patient’s eye within
the target.
As the focusing indicator is displayed,
manipulate the joystick until the optimum focusing indicator is displayed.
• If the mire ring is not in the center of the pupil and the minimum pupil circle is on the iris,
turn off the auto-tracking function and bring the minimum pupil circle into the center of the
pupil to perform measurement, ignoring the mire ring.
• Auto-tracking or auto-shooting may not work on keratoconus or postoperative cornea.
In such a case, turn off the auto-tracking and auto-shooting functions.
Mire ring Target
Focusing indicator
Focusing: Manual
Up-and-down alignment: Auto
Side-to-side alignment: Manual