CSO POLARIS, Instructions For Use Manual, Page: 42 / 48

INSTRUCTIONS FOR USE
POLARIS | IFU312EN00
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4.11 HOW TO ANALYZE THE CORNEAL SURFACE REGULARITY
1 Place the Placido's disk film on the device lighting system as
explained in the paragraphHow to insert the film in the device
lighting head at page 33.
2 Ask the patient to look ahead and open and close the eyes for
a few seconds, so that the tear film is evenly distributed on the
corneal surface.
3 Observe the image reflected on the corneal surface. A regular
corneal surface will result in a reflected image with concentric
rings, all at the same distance. Any irregularities in the corneal
surface of the will result in irregularities of the reflected
image. Closer rings correspond to areas of steeper curved
cornea, while more distance between rings correspond to
flatter cornea area.
Fig 29 - Placido's disk reflection