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Carl Zeiss Meditec IOL Master
Cataract Surgery Arizona

IOLMaster — Axial Length Measurement
Moderate to Dense Cataract.


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 distance independent.

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.