Related Manuals for DGH 3000B
Summary of Contents for DGH 3000B
- Page 1 DGH 3000B ULTRASONIC A-SCAN OPERATOR’S MANUAL SYS.SBH REV. 12/98 DGH Technology, Inc. Sales: (800) 722-3883 www.dghkoi.com 110 Summit Drive; Suite B Phone: (610) 594-9100 Exton, PA 19341 Fax: (610) 594-0390...
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Page 3: Table Of Contents
Explanation Of Display Messages ............ 21 VIII. Manual Gain Control..............24 Test Block Mode................. 26 Diagnostic Mode................. 28 Setting Up The DGH 3000B For IOL Computations......29 XII. The Holladay Formula And The Personalized Surgeon Factor....35 XIII. IOL Calculation Instructions............42 XIV. -
Page 5: Introduction
INTRODUCTION Ultrasound is sound of a frequency level too high to be heard by the human ear; however, sensitive equipment can send and receive these ultrasonic impulses as well as analyze information about anything these impulses strike along their route of travel. Every time a sound impulse strikes an interface, some sound is reflected (bounces off), and some sound is refracted (passes through). - Page 6 Figure C Figure D The DGH 3000B A-Scan incorporates a very sophisticated pattern recognition program that automatically checks for proper alignment. It looks for the proper pattern of spikes as well as going a major step further by looking at the retinal spike for particular signal characteristics which are produced only by retinal interfaces.
- Page 7 Most ophthalmic ultrasonic units use an average speed of sound of 1550 m/s for phakic eyes and 1532 m/s for aphakic eyes. The DGH 3000B is programmed to automatically use the proper speed for the eye you wish to read.
- Page 8 A-Scans on the market are able to produce these. The DGH 3000B displays values for the anterior chamber, lens thickness, and axial length automatically each time a reading is made.
- Page 9 cornea is 1.376, but to obtain an approximation of the true refracting power of the cornea from only the radius of the anterior surface, a fictitious refractive index has to be used. This index varies with the make of keratometer. Common values are: 1.3375 (Haag-Streit, Bausch and Lomb) 1.336...
- Page 10 stronger power, and inserting the implant with the convex side backwards necessitates an even stronger lens. Implant Power The implant power is measured differently by different manufacturers. This can result in variations between IOL companies. Formulas Used There are basically two classifications of IOL formulas - Theoretical and Regression.
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Page 11: Features
FEATURES The DGH 3000B A-Scan is manufactured with high quality components that are designed and built using the latest technological concepts. The result is an advanced and powerful A-Scan that offers practicality and reliability. The following features are just a sample of the characteristics and capabilities of this unique unit. -
Page 12: General Description
III. GENERAL DESCRIPTION Front Panel Paper Door Latch When the thermal printer paper needs replacing, this latch is used to gain access to the twenty-eight column thermal graphics printer. The printer provides the operator with a permanent record. LED Bar Graph The LED bar graph consists of three columns of multi-colored LED’s used to indicate the amplitude of the anterior lens echo, posterior lens echo, and retinal echo respectively. - Page 13 This lever releases the thermal paper from the printer platen. “NEXT” - Next Entry Used to advance to the next entry during the setup (configuration) of A-Scan or IOL parameters. “SETUP” - Setup (Configure) Used to initiate and terminate the setup (configuration) of A-Scan or IOL parameters.
- Page 14 “IOL” - IOL Calculations Used to enable the IOL calculations. “PREV” - Previous Entry Used to reverse to the previous entry during the setup (configuration) of A- Scan or IOL parameters. “SELECT” Used to scroll through program options presented on the display. “DELETE”...
- Page 15 Firmware module where the IOL calculation formulas are stored. Unit Model Number & Serial Number Location of the model number and serial number for the DGH 3000B. These numbers are used to identify the unit. IOL Calculation Firmware Module Serial Number Location of the serial number for the IOL calculation firmware module.
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Page 16: Power-Up And Programming Sequence
The unit will perform an internal self-test function and display the results. The display will also indicate whether or not an IOL Firmware Module is installed. The DGH 3000B will automatically set the internal gain of the unit to comply with the probe sensitivity. - Page 17 “Normal”, “Aphakic”, or “Pseudophakic” (the default is “Cataractous”). Press “ENTER” to confirm your selection. When the desired lens type is chosen, the appropriate program parameters for alignment criteria and velocity of sound are automatically installed so no further changes need to be made. NOTE: If the pseudophakic lens type is selected, the display will prompt the operator to select an artificial lens type: “PMMA”, “Silicone”, or “Other”.
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Page 18: A-Scan Measurements
A-SCAN MEASUREMENTS Perform the Power-up and Programming Sequence as described in Section IV. Position the unit for easy visibility during patient examination. Seat or lay the patient in a comfortable position so that the head can be positioned in almost a horizontal plane. Use a firm, comfortable head rest to prevent unwanted head movement. - Page 19 11. If the beep rate reaches a constant tone during the alignment procedure, cornea indentation may be occurring. The DGH 3000B uses special circuitry that prohibits any measurements from being obtained if the cornea is being indented. If a constant tone is obtained, slowly withdraw the probe away from the cornea until the constant tone changes to pulsed beeping.
- Page 20 2. 14. The measurement and storage of up to eight (8) different readings for each eye is possible with the DGH 3000B, depending on how many measurements the operator feels is necessary to evaluate for consistency and repeatability.
- Page 21 “SELECT EYE OD”. * * * CAUTION * * * When the unit is CLEARED, the DGH 3000B will automatically set the internal gain of the unit to comply with the probe sensitivity. Therefore, it is imperative that the probe tip be clean and dry before the unit is cleared.
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Page 22: Setting Up The Dgh 3000B
SETTING UP THE DGH 3000B Setup (Configuration) Overview The DGH 3000B has been designed to allow the operator to set up certain default parameters to tailor the instrument to one’s needs. These parameters are permanently stored in non-volatile memory and are automatically recalled from that memory each time the unit is powered up. - Page 23 display will advance to the next configurable parameter. You may now configure the remaining parameters in a manner similar to step 3. Configuration values for any non-numerical parameters can be obtained by pressing the “SELECT” key. Always remember to confirm a new parameter value by pressing the “ENTER”...
- Page 24 After the “AVERAGE PRINTOUT” parameter has been entered, the display will read: WRITING NVM PLEASE WAIT for several seconds, and then the display will read: 1 OD(S) AUTO GAIN NO MEASUREMENT At this point, the operator’s selected values for all parameters have been permanently stored in non-volatile memory and will not change (even when power is removed) unless deliberately changed by the operator by re-entering the A-Scan setup mode as described above.
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Page 25: Explanation Of Display Messages
EXPLANATION OF DISPLAY MESSAGES Display Messages Overview The DGH 3000B provides feedback to the operator in the form of messages on the front panel display. These messages will appear if the operator has not been able to obtain a measurement after the probe has been applanated to the cornea for a preset time period. - Page 26 the operator presses the “ENTER” key within the five second wait period as prompted by the “ENTR TO OPEN LIM” message, the limit criteria used to determine if valid lens or retinal echoes are present are opened up, i.e., it should be much easier to get a measurement.
- Page 27 If the operator does not intervene within five seconds, the DGH 3000B will automatically increase the internal gain required to obtain a measurement on the next attempt. This will be indicated on the display as “AUTO GAIN ADJUST REATTEMPT MEAS”.
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Page 28: Manual Gain Control
MANUAL GAIN CONTROL Manual Gain Control Overview The DGH 3000B is preset at the factory with internal system gains that have been determined to be adequate to obtain measurements in most cases. Under certain conditions, however, such as an extremely dense cataract, these preset gains may prove to be inadequate. - Page 29 Once the manual gain control mode has been entered, the DGH 3000B will begin all subsequent measurement attempts at the gains entered by the operator until either the “CLEAR” or “AUTO GAIN” key is pressed, or the power to unit is turned off and on.
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Page 30: Test Block Mode
For this reason, the DGH 3000B must be placed into a test block mode to allow measurement of the plastic block used as a reference for calibration verification. - Page 31 11. If the reference block readings are outside the limits stated above, it is possible that the unit is defective and needs repair. Contact the Customer Service Department of DGH Technology, Inc. at (610) 594-9100 to arrange for return for repair.
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Page 32: Diagnostic Mode
DIAGNOSTIC MODE Diagnostic Mode Overview The DGH 3000B has the unique capability to provide diagnostic data to the operator and/or service personnel. This diagnostic data can be used in three ways: As feedback to service personnel should any problem develop with the DGH 3000B. -
Page 33: Setting Up The Dgh 3000B For Iol Computations
• Surgeon Factor • Default IOL Configuration Number The DGH 3000B allows the user to customize the printout and store constants for up to eight different lenses. This combination of printout design and lens constants is referred to as an “IOL configuration”. - Page 34 Personalized Surgeon Factor (PSF) as described in Section XII. Default 1 to 8 The number of the IOL configuration that the DGH 3000B will default to Configuration each time an IOL computation is performed. Number...
- Page 35 Inputting the IOL Computation Parameters The setup procedure for inputting the parameters for each IOL configuration is as follows: Turn the unit on and wait until the display reads: SELECT EYE Press the “ENTER” key twice. The display will read: 1 OD AUTO GAIN NO MEASUREMENT...
- Page 36 Use the “SELECT” key to display the formula of your choice: “SRK/T”, “Holladay”, “Binkhorst”, or “SRK II” (the default is “SRK/T”). Press “ENTER” to confirm your selection. The display will read: SELECT IOL TYPE POSTERIOR Use the “SELECT” key to display the lens type: “Posterior” or “Anterior” (the default is “Posterior”).
- Page 37 12. Use the numeric keypad to enter the number “N” (1 thru 8) of the IOL configuration that you wish the DGH 3000B to default to each time an IOL computation is performed. It is suggested that the configuration number for the most frequently used lens be entered.
- Page 38 Table 3 Corresponding values for the A-Constant, Binkhorst ACD, and Surgeon Factor Surgeon Surgeon Surgeon Factor Factor Factor 114.0 2.63 -1.04 116.0 3.80 0.09 118.0 4.97 1.22 114.1 2.69 -0.99 116.1 3.86 0.15 118.1 5.02 1.28 114.2 2.75 -0.93 116.2 3.91 0.20 118.2...
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Page 39: The Holladay Formula And The Personalized Surgeon Factor
Intraocular Lens Power Calculations” gives the theory of the formula and also describes the study showing the improved accuracy of the formula. (Copies of this article are available upon request from DGH Technology, Inc.) As stated in the article, the three parts of the system are as follows: The Holladay formula using the “Basic Surgeon Factor”. - Page 40 SPHERE and CYLINDER are from the postoperative refraction. These should be stabilized results with a 20/40 or better acuity. STEP 2 Enter Data into the DGH 3000B Turn the unit on and wait until the display reads: SELECT EYE Press the “ENTER”...
- Page 41 “Import” allows you to transfer data from one configuration to another. The DGH 3000B has this capability, but it is recommended that you contact the Customer Service Department for detailed instructions.
- Page 42 If an error is found, choose “Edit” and enter the case number that is to be corrected. When you have made the corrections, the menu in step 6 will reappear. At this point, you may either “Abort” or “Save and Exit”. “Abort” erases all data entered in this succession.
- Page 43 IOL calculation. This screening identifies the majority of large refractive surprises preoperatively. The DGH 3000B automatically screens input data and A-Scan measurements for statistically unlikely values and flags them with either two or three asterisks on the printout.
- Page 44 IOL Parameters --- Cross Check Indicates that one of the values entered for A-Constant, ACD, or Surgeon Factor is not in agreement with the others. Check the values entered for these parameters and enter the correct values. - 40 -...
- Page 45 Table For Data Collected From Patient Files Patient Axial Sphere Cylinder Length Power - 41 -...
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Page 46: Iol Calculation Instructions
Introduction After the IOL Computation Setup has been completed (as described in Section XI), the DGH 3000B is ready to perform IOL calculations. When equipped with the Firmware Module SYS: A34SBH, the DGH 3000B will perform four IOL formulas: SRK/T™, SRK II™, Holladay Dioptimum™, and Binkhorst II. - Page 47 Turn the unit on and wait until the display reads: SELECT EYE Use the “SELECT” key to display the eye being measured: “OD” or “OS” (the default is “OD”). Press “ENTER” to confirm your selection. The display will read: SELECT LENS TYPE CATARACTOUS Use the “SELECT”...
- Page 48 CONFIG NMBR where “N” is the number of the default IOL configuration selected in step 11 of Section XI. Press “ENTER” if you wish to accept this default configuration. If you would like to change the configuration number to any other pre-defined IOL configuration, use the numeric keypad to select the appropriate number (1 thru 8) and then press the “ENTER”...
- Page 49 valid axial length for the operative eye. Once a valid axial length is displayed, press “ENTER” to confirm the number. The display will read: FELLOW EYE K1 0.00 11. Use the numeric keypad to enter the first keratometer reading (in diopters) for the fellow eye.
- Page 50 “Y.YY”. 15. If desired, use the “NEXT” and “PREV” keys to review on the display the four IOL powers (in approximately half-diopter increments) above and below selected IOL power. * * * CAUTION * * * Reviewing the calculated IOL powers on the display should be used as a preliminary screen only.
- Page 51 indicating the selected formula. vi) The calculated IOL powers for emmetropia on the fellow eye. Calculations using all four formulas are shown, with an asterisk indicating the selected formula. vii) The target IOL power, i.e., the IOL power required to produce the selected postoperative refraction.
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Page 52: Important Notes
XIV. IMPORTANT NOTES Caution ! The probe is fragile and extreme care must be taken in its handling. Sterilize the probe with either cold soak or ethylene oxide only. DO NOT AUTOCLAVE ! Loading Paper Into Printer When the printer paper is almost exhausted, a colored stripe will appear on the paper. - Page 53 Service Should service be necessary, contact the customer service department at: DGH Technology, Inc. TECHNOLOGY, INC. 110 Summit Drive, Suite B Exton, PA 19341...
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Page 54: Warranty
This warranty is strictly limited to replacement or repair of the part which is found to be defective in material and workmanship. At the option of DGH, said part shall be replaced or repaired free of charge, F.O.B. our factory by DGH. -
Page 55: Specifications
XVI. SPECIFICATIONS Shipping Weight ................15 pounds Weight ..................12 pounds Height..................5.5 inches Width ..................12.5 inches Depth ..................12.0 inches Power ............100-120 or 200-240 VAC, 50-60 Hz Probe Length ................2 inches Probe Diameter (Handle).............. 0.25 inches Probe Diameter (Tip) ..............
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