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Comparison of axial length and IOL power obtained by Nidek AL-Scan vs Nidek AL-Scan with ultrasound for IOL calculation in highly myopic eyes

Poster Details

First Author: A.Kulak TURKEY

Co Author(s):    Y. Totan   E. Guler   F. Guragac        

Abstract Details

Purpose:

This study aims to compare the axial lenght (AL) and IOL power obtained by Nidek AL-Scan (Nidek CO, Aichi, Japan); optical and ultrasound biometry in highly myopic eyes.

Setting:

Turgut Ozal University Hospital, Department of Ophthalmology, Ankara, Turkey.

Methods:

25 eyes from 25 patients who underwent phacoemulsification and IOL implantation with Tecnis 1-piece aspheric acrylic IOL were included . Measurements of all eyes were taken using Nidek AL-Scan. Axial Length measured by optical and ultrasonic methods. AL-Scan uses 2.4 mm keratometric(K) values for optical and 3.3 mm K values for ultrasonic methods when IOL calculation. We used SRK-T formula to determine the IOL power. The mean difference between the prediction with each method and the final spherical equivalent was compared. Agreement of axial length and IOL power between the 2 methods were evaluated by the Bland-Altman method.

Results:

The axial length taken by optical was slightly longer than the ultrasound. (27.15±0.69 mm for optical, 27.03±0.62 mm for ultrasound p=0.04). K mean derived from 2.4 mm was 42.87±2.03 D and derived from 3.3 mm was 42.75±1.86 D. The mean IOL power was 11.08±3.42 D in optical biometry group and was 11.26±3.20 D in ultrasound biometry group respectively. (p=0.236). Mean absoute errors were 0.07±0.05 and 0.28±0.20 respectively. limits of agreements (LoA) were for AL 0.36 to 0.60 mm (p=0.08) and for IOL power -1.51 to 1.15 D (p=0.13).

Conclusions:

The IOL power and axial lenght derived from both groups were similar. The agreements between them were high in myopic eyes.

Financial Disclosure:

NONE

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