Zeiss IOLMaster Customer Service: 1-877-486-7473 ext.
IOLMaster — Axial Length Measurement
Moderate to Dense Cataract.
Measuring a Dense Cataract
In measuring a dense cataract, the IOL Master axial length display will
typically show the above characteristics. The secondary maxima are usually
absent, lost within a high and uneven baseline. As long as the primary
maxima is narrow, and has a well-defined and centered terminal peak, the
measurement can still be considered valid.
If the signal-to-noise ratio of the eye to be measured is borderline
(2.0 to 1.6), focusing in, or focusing out, in such a way that
that focusing spot enlarges to about the same size as the measurement
reticule, will sometimes significantly improve the quality of the
axial length display. This is possible with the IOL Master because
axial length measurements by partial coherence interferometry are
Remember to use the Best Measurement Technique,
sampling several areas around the center of the reticule until
the best display is obtained. The important components of accuracy
with the IOL Master are: correct alignment with the fixation light,
measurement consistency, and a correct display pattern. The the
IOL Master has an uncanny ability to correctly find the retinal
pigment epithelial reflection. Experience has shown that even measurements
with a signal-to-noise ratio of 1.6 are usable.