Zeiss CIRRUS HD-OCT 500, Руководство пользователя

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CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Criteria for Image Acceptance
7-11
Anterior Segment Acceptance Criteria
General
Anterior Chamber, Wide Angle-to-Angle, HD Cornea, HD Angle, and Pachymetry scans are
corrected to account for beam scanning geometry and refraction on the corneal surfaces.
These corrections are most accurate when acquired corneal scans are centered on the
corneal vertex, which generates a strong central reflection line on the live OCT image.
Typically the corneal vertex is just to the nasal side of the pupil center.
Anterior Segment Cube Scan
The operator is advised to evaluate the scanned image prior to making CCT measurements.
The corneal image should have well–defined posterior and anterior surfaces, should not
have excessive motion artifacts and corneal reflections on the central cornea, especially
within the area where the measurement caliper is to be placed.
NOTE: CCT measurements may be easier to obtain on HD Cornea or Anterior Chamber
scans.
The following conditions may affect the ability to obtain a good corneal image for CCT
measurements:
1. Inability of the patient to maintain fixation, including patients with poor visual acuity.
2. Excessive corneal reflection resulting from certain intra-ocular lenses, corneal
abrasions and corneal opacities.
3. Presence of contact lenses. The junction of some contact lenses and the corneal
surface may not be easy to visualize. Patients should remove contact lenses prior to
scanning for a CCT measurement.
Pachymetry Scan
Sequence through slices of the radial scan lines of a Pachymetry scan by clicking any one of
the 24 radial scan lines displayed on the iris image.
Any one of the following methods may be used:
• Click an OCT B-scan image and use the mouse scroll wheel.
• In full screen mode, use the scroll bar at the right side of the image.
• Use the movie controls.