Zeiss CIRRUS HD-OCT 500, User Manual

Page: 88 / 352

Anterior Segment Scans
2660021169012 Rev. A 2017-12 CIRRUS HD-OCT User Manual
6-16
Guidelines for Wide Angle-to-Angle Acquisition
• Attach the external Anterior Chamber lens to the instrument lens mount, see
"Anterior Chamber and Cornea External Lenses" on page 6-7 .
• Instruct the patient to fixate on the center of the fixation target even though it may
not appear to be in focus.
• If the anterior chamber seems tilted, instruct the patient to shift his/her gaze slightly to
the left or right as needed to horizontally orient the anterior chamber.
• Click the center of the pupil and use the X, Y and Z controls or keyboard arrow keys
and mouse scroll wheel to center the scan on the corneal vertex with both iridocorneal
angles, iris, and pupil visible in the OCT scan display area and the anterior of the
cornea extending slightly out of the field of view, as shown in
Figure 6-9 .
NOTE: A strong vertical central reflection line on the B-scan indicates the scan is centered
on the corneal vertex.
NOTE: For the Wide Angle to Wide Angle scan, the iris will be slightly out of focus even
when correctly aligned.
Pachymetry
This scan consists of 24 radial scan lines with a scan depth of 2.0 mm that are used to
generate a color-coded thickness map of the cornea. The scan uses 24 B-scans, each
composed of 1024 A scans. This scan requires the Cornea external lens. The Pachymetry
scan is used as the basis for the Pachymetry Analysis. (See
"In Pachymetry Analysis"
on page 8-44 for more information.)
The Acquire screen displays the position of the Pachymetry scan pattern on the live iris
image. The images on the right display the temporal/nasal and inferior/superior scans of
the selected meridian. The Pachymetry scan requires the Cornea external lens.