MAY 17, 2010
This prospective study compared measurements taken with the IOLMaster biometer, which uses partial coherence interferometry, and the newer Lenstar LS 900 biometer, which uses optical low-coherence reflectometry. Researchers evaluated 50 patients (50 eyes) undergoing cataract surgery and 50 patients (50 eyes) with a clear lens. Axial length (AL), anterior chamber depth (ACD) and K measurements taken with the two devices in cataractous and normal eyes correlated well.
The Lenstar measured a slightly longer AL, a deeper ACD and flatter K, differences that were statistically significant. However, the clinical relevance of these differences was insignificant when performing IOL power calculations. The Lenstar evaluates 32 light points from the anterior corneal surface and measured, on average, a 0.11 D flatter cornea than the six light point measurements taken with the IOLMaster.
The Lenstar also evaluates crystalline lens thickness, a boon to physicians using formulas that require precise ACD and lens thickness measurements, such as Holladay II and Olsen. Without this device, surgeons using these two formulas have to measure lens thickness by ultrasonography. Thus, the Lenstar's additional central corneal thickness and ACD measurements will be valuable for performing refractive IOL surgery.
The authors conclude that measurements taken with the IOLMaster and Lenstar are clinically interchangeable. They found the Lenstar to be user friendly, although obtaining AL measurements was slightly more time-consuming than with the IOLMaster.