Reflectometry Versus Partial Coherence Interferometry

 To compare biometric measurements of the IOLMaster partial coherence interferometry biometer (Carl Zeiss Meditec) and the Lenstar optical low coherence reflectometry biometer (Haag-Streit AG, Koeniz, Switzerland). The accuracy of intracular lens (IOL) power calculation using the variables obtained by the 2 machines was analyzed after performing uneventful cataract surgery.

Elsafwa eye center, Alexandria, Egypt 

 This prospective study included 50 eyes of 50 patients who were scheduled for cataract surgery. One eye of each patient was examined using both IOLMaster (Software version 5.4) and Lenstar LS 900 (Software version 2.20) biometers. Axial length, anterior chamber depth (ACD), and keratometric (K) readings were measured  by the 2machines and recorded. All cases underwent routine uneventful  phacoemulsification surgery and a foldable hydrophobic acrylic intraocular lens (Tecnis ZCB00, Abbott Medical Optics, Abbott Park, Illinois, USA)  was injected in the bag by the same surgeon. The IOL prediction error was calculated.

The mean axial length measured by the Lenstar LS 900 was longer than that of IOL Master by 0.0142 mm (P = 0.086). The mean K readings measured by the IOL Master was deeper than that of Lenstar LS 900 by 0.085 D (P = 0.012). The mean ACD measured by the Lenstar LS 900 was deeper than that of IOL Master by 0.057 mm (P < 0.0001). Using the SRK/T formula, the mean absolute error with Lenstar LS 900 was lower than that of IOLMaster by 0.044 D (P = 0.024). While using the Haigis formula, the mean absolute error with Lenstar LS 900 was lower than that of IOLMaster by 0.026 D but was not statistically significant (P = 0.278).For both formulas, the IOL prediction error of all cases was within + 2 Diopters.

 Both Lenstar LS 900 and IOLMaster got accurate results for IOL power calculation. Lenstar LS 900 provides extra measurements such as lens thickness that can be used in other IOL power calculation formulas as Holladay II.