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

Session Details

Session Title: Cataract Surgery Equipment. Cataract Surgery Outcomes

Session Date/Time: Monday 07/09/2015 | 16:30-18:30

Paper Time: 16:36

Venue: Main Auditorium

First Author: : P.Hoffmann GERMANY

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

Abstract Details

Purpose:

To evaluate if data sets generated with the IOLMaster 700 are freely interchangeable with the Lenstar LS 900 for the purpose of IOL calculation.

Setting:

Augen- und Laserklinik Castrop-Rauxel, Deutschland / Germany

Methods:

143 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 all 143 eyes (100%) while Lenstar could not measure 6 eyes (4.2%). Axial lengths had a mean absolute difference (MAD) of 0.020 mm which is well inside the measuring tolerance of either machine; no clinically relevant outliers existed. MAD of mean corneal radius was 0.024 mm with 14.0% outliers. MAD of crystalline lens equator position was 0.088 mm with no outliers. Using error propagation, we calculated the contribution of raytracing-computed IOL power difference as follows: axial length 12%, corneal radii 64%, crystalline lens equator position 24%. Difference between astigmatic vectors was 0.41±0.30 dpt.

Conclusions:

No systematic differences exist concerning axial length, corneal radii, anterior chamber depth and lens thickness. Stochastic differences are 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 Interest:

NONE