Proposed Screening Parameters - OCULUS Pentacam Interpretation Manual

10 Screening for refractive surgery

10.1.2 Proposed screening parameters

It is essential to check the settings for the fitting zone of the BFS in the settings of the Pentacam®,
since this influences the borderline numbers
Figure 57: BFS fitting zone
If you are using the manual (fixed) 9 mm zone for fitting the BFS, the proposed screening
„ „
parameters I use are:
In the anterior elevation map differences between the BFS and the corneal contour less than
+12 μm are considered normal, while differences between +12 μm and +15 μm are suspicious,
and differences > 15 μm are typically indicative of keratoconus. Similar numbers about 5 μm
higher apply to posterior elevation maps
If you are using the manual (fixed) 8 mm zone for fitting the BFS, the proposed screening
„ „
parameters I use are:
Anterior elevation differences less than 8 μm are considered in the normal range, while
differences > 8 μm are typically indicative of keratoconus or other ectatic disorders (in the
central zone). Posterior elevation differences < 11 μm are considered in the normal range,
while differences >16 μm are suspicious
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(Figure 57).