Posters

Comparison of two different biometers able to measure partial sections of the optical path (IOLMaster 700 and Lenstar LS 900)

Poster Details

First Author: P.Hoffmann GERMANY

Co Author(s):    M. Abraham   L. Zumhagen           

Abstract Details

Purpose:

To evaluate data sets generated with the IOLMaster 700 and Lenstar LS 900 for the purpose of IOL calculation.

Setting:

Private eye clinic in Germany

Methods:

497 cataractous eyes were measured with the Zeiss IOLMaster 700 as well as the Haag-Streit-Lenstar LS 900. Descriptive analysis was carried out on the following parameters: axial length, corneal radii, corneal thickness, anterior chamber depth, lens thickness. Derived values like astigmatism and crystalline lens equator position (= internal anterior chamber depth + 40% of lens thickness) were analyzed separately. Clinical outliers were defined as data that would lead to a calculated IOL power difference of 0.25 D or more.

Results:

IOLMaster 700 could measure the axial length in 99.2% of eyes while Lenstar could measure 97.1% of eyes. Axial lengths had a median absolute difference (MAD) of 0.02 mm; 1.8% of data pairs were clinically different. MAD of mean corneal radius was 0.02 mm with 8.4% outliers. MAD of crystalline lens equator position was 0.03 mm with 1.0% outliers. Mean astigmatic difference vector was 0.41 ± 0.30 D of cylinder. Using error propagation, we calculated the contribution of raytracing-computed IOL power difference as follows: axial length 29%, corneal radii 59%, crystalline lens equator position 12%.

Conclusions:

No systematic differences exist concerning axial length, corneal radii, anterior chamber depth and lens thickness. Stochastic differences are also low for all variables except corneal radii, which also have the greatest contribution to IOL power calculation differences. In clinical practice, data sets between both machines are freely interchangeable so that software packages like Okulix or PhacoOptics that have been calibrated with Lenstar data can also be used with the IOLMaster 700 FINANCIAL DISCLOUSRE: NONE