The Zeiss IOL Master was approved by the United States FDA in 2000. A non-contact optical device that measures the distance from the corneal vertex to the retinal pigment epithelium by partial coherence interferometry, the Zeiss IOL Master is consistently accurate to within ±0.02 mm or better. The IOL Master is the first such device to be widely used in clinical ophthalmology. Calibrated against the ultra-high resolution 40-MHz Grieshaber Biometric System, an internal algorithm approximates the distance to the vitreoretinal interface, for the equivalent of an immersion A-scan ultrasonic axial length.

Considering the fact that axial length measurements by A-scan ultrasonography (using a standard 10-MHz transducer) have a typical resolution of 0.10 mm to 0.12 mm, axial length measurements by the IOL Master represent a fivefold increase in accuracy.

The IOL Master allows fast, accurate measurements of eye length and surface curvature, necessary for cataract surgery. The IOL Master is extremely efficient as it allows measurements to be taken with complete confidence in the accuracy of the results. Also, because the IOL Master is non-contact, there is no need for anesthesia and there is no potential for spread of contamination from the IOL Master.