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Evaluation of a new optical biometry device for measurement of ocular biometric parameters and its comparison with conventional ultrasound biometer

Poster Details

First Author: C.Caglar TURKEY

Co Author(s):    S. Doguizi   H. Zirig   E. Demir   M. Durmus           

Abstract Details


To evaluate the intraobserver repeatability and interobserver reproducibility of ocular biometric parameters (central corneal thickness, anterior chamber depth (ACD), keratometry over 2.4 mm and 3.3 mm diameter, axial length (AL), white to white, and pupil distance) and intraocular lens (IOL) power measurements with a new optical biometry device (ALScan; Nidek, Japan) and compare these measurements with those of the ultrasound biometry (ALScan; Nidek, Japan) in patients with senile cataract.


This was a prospective study that included 75 consecutive eyes of 75 patients with senile cataracts between February and March 2015 in the Ophthalmology Department of Hitit University, Corum, Turkey.


Optic and ultrasound biometric measurements were performed by the three different experienced examiners using the optic and ultrasound biometry. Each examiner performed 3 consecutive measurements with optic biometer (intraexaminer repeatibility). Then, the second and third examiners performed another measurement with optic biometer (interexaminer reproducibility). Finally, the first examiner performed one measurement with ultrasound biometer to evaluate the agreement of two measurement methods. Data obtained from each instrument were used to calculate IOL power using the SRK-T formula, targeted for emmetropia. Intraclass correlation coefficient (ICC) was calculated for repeatability and reproducibility. Repeatability of measurements was also evaluated by Bland Altman analysis.


The mean age of patients was 68±10.28 (range, 50 to 84 years). The repeatability and reproducibility for all ocular biometry measurements were very high. The ICC of AL was highest for intraexaminer repeatability. The ICC of ACD was highest for interexaminer reproducibility between all parameters. Comparing the two instruments’, ACD, AL and IOL power measurements were compared using paired samples t-test, a significant difference was found. The mean value of all measurements and calculated IOL power showed a good ICC between two devices. The AL-Scan produced slightly lower IOL power calculation readings (0.46 D).


We found that excellent repeatability and reproducibility for all biometric parameters and IOL power by the AL-Scan. The correlation between optic and ultrasound biometry was also found high. The difference in ACD, AL and IOL between two devices was statistically significant but clinically it was negligible. These results suggest that the new biometer can be used for routine cataract practice to obtain reliable biometry measurements for IOL power calculation. This device is easy and comfortable to use and performs rapid, repeatable and reproducible measurements.

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