OM t of c.iii - Vision Research Coordinating Center - Washington ...

1/1/2005 Chapter 8 Corneal Curvature and Topography page 8-23
The Mastervue unit is an alternative means of collecting videokeratography data
for clinics not equipped with a TMS unit. It is currently being utilized at the Nova
Southeastern Participating Clinic. Data are stored on site.
8.7.1 Calibration Verification
Calibration of the Mastervue unit is performed weekly throughout the course of
data collection for the CLEK Study.
The calibration procedure is as follows:
(1) Place the frame of the calibration bar in the two holes located at the base of
the chin rest.
(2) Select Utilities from the Main Menu.
(3) Select Run Calibration from the Utilities Submenu.
(4) Position the projection head in front of the 35 D sphere.
(5) Select OK.
(6) Align the projection head by centering the cross hairs in the smallest ring of
the image. Use the joystick to focus the image. Press the button on the joystick to
capture the image. If the image capture is within an acceptable value, the word
“passed” will be displayed on the screen; if not within an acceptable value, the word
“over” or “under” will be displayed along with the actual dioptric value. To continue
the calibration procedure, select Yes; to repeat the measurement of the 35 D sphere,
select No.
(7) Repeat the above procedure for the 42.25 D and 55 D spheres.
(8) Final results will be displayed on the screen. Maintain a record documenting
weekly calibration. If the machine is improperly calibrated, contact Humphrey
Instruments Technical Support for assistance at 800-227-1508. If machine cannot be
recalibrated properly prior to patient visit, continue with the examination protocol.
Following the examination, complete a Feedback Report documenting the calibration
results only if a calibration error occurred. Submit the Feedback Report with patient
record and maintain copies in the Clinic patient record and Clinic calibration record.
8.7.2 Humphrey Mastervue Patient Confidentiality
Patient confidentiality is maintained as follows: