CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12Tracking and Repeat Scans 6-354. To achieve uniform illumination, ensure the scan beam is aimed through or near thecenter of the pupil and the iris and pupil are in focus. Corneal opacities may beminimized by realignment of the pupil. This can be assessed and adjusted in the iriscamera viewport.5. Proper focusing is essential for a good fundus image. This is accomplished by usingAuto Focus or by manually adjusting focus. The user may also set the patient'sspherical equivalent values when adding or editing the patient demographicinformation.6. Select Track to Prior. If the border around the Capture button remains red, alignmentmay not be working. Change which prior scan to track to or disable Track to Prior forthis scan. Track to Prior is possible for scans acquired before the tracking license wasactivated or for which tracking was not turned on. However, optimal results can beobtained by selecting a prior scan for which tracking had been on.When the Track to Prior feature is turned off and a Prior Scan is chosen, the CIRRUSoperates as described in "Repeat Scans" on page 6-327. When the border around the Capture button is green, the scan can be performed withFastTrac. Click Capture.During FastTrac acquisition, after clicking Capture, a screen appears that shows the scan inprogress as shown in Figure 6-20, and provides controls to make adjustments to helpcomplete the scan.A tracked scan may take additional time as compared to a non–tracked scan. During thisperiod, adjustments may be necessary to maintain the success of tracking and the qualityof the acquired scan.The information box below the progress bar has two indicators to clarify if the conditionsfor a successful FastTrac scan are being met. When FastTrac is interrupted, information boxindicators and the progress bar turn red and the progress bar stops.The user can stop the scan for any reason from this screen by clicking Cancel one time. Theprogress bar will complete but the scan will not be captured. The user is then returned tothe Acquire screen to try again or finish.NOTE: After five minutes on the Scan in Progress screen with no scan being acquired, thesystem will return to the Acquire screen.NOTE: Unlike non–tracked scans, once scanning has started, you may advise the patient toblink normally, as needed, while maintaining focus on the fixation target. Additional tearfilm may improve the signal of the scan.
