Topcon ALADDIN - Errors in Measurements

ALADDIN - User manual Rev. 23 of 08/07/2016
51
Errors in Measurements
Sometimes the measurement is taken in one of these conditions: bad
focus, closed eyelid, tear film irregularity, high standard deviation in
multiple measurements, movement, measurement not in range; in this
case, a warning sign appears above the measurement.
ATTENTION: When the symbol is shown above a measurement, it means that the software recognized
an error during the acquisition, which are bad focus, closed eyelid, tear film irregularity, high standard
deviation in multiple measurements, movement, measurement not in range.
Figure 32
The possible problems in acquisition are found in the software with the following methods:
Error cause
Identification
Closed eyelid
Missing ring reflection on the eye Placido Image, on the upper
hemisphere of the cornea
Movement
Interlace pattern shown in acquired image
BrokenTear film
Missing ring reflection on the eye on Placido Image
Bad focus
Defocus of ring reflection on acquired image
High standard deviation on repetition
Big difference between repeated acquisitions
Measurement not in range
Output out of instrument range of measurement