Sung In Kim; Sug Jae Kang; Tae Hoon Oh; Jin Seok Choi; Nam Ho Baek

doi:10.3341/jkos.2013.54.11.1688

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Kim, Kang, Oh, Choi, and Baek: Accuracy of Ocular Biometry and Postoperative Refraction in Cataract Patients with AL-Scan®R

Original Article

J Korean Ophthalmol Soc 2013;54(11):1688-1693.

Published online: 2 September 2013

DOI: https://doi.org/10.3341/jkos.2013.54.11.1688

Accuracy of Ocular Biometry and Postoperative Refraction in Cataract Patients with AL-Scan®R

Sung In Kim, MD, Sug Jae Kang, MD, Tae Hoon Oh, MD, Jin Seok Choi, MD, PhD, Nam Ho Baek, MD, PhD

Department of Ophthalmology, Saevit Eye Hospital, Goyang, Korea

Address reprint requests to Tae Hoon Oh, MD, Department of Ophthalmology, Saevit Eye Hospital, #1065 Jungang-ro, Ilsandong-gu, Goyang 410-817, Korea, Tel: 82-31-900-7700, Fax: 82-31-900-7777, E-mail: 76drhoon@hanmail.net

Received 29 March 2013 Revised 15 June 2013 Accepted 8 September 2013

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict post- operative refractions of AL-Scan®, IOL master®, and ultrasound.

Methods

A total of 40 eyes in 30 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured by 2 types of partial coherence interferometry (AL-Scan® and IOL master®) and ultrasound. The SRK/T formula was used to calculate IOL power, and the predictive error which subtracts predictive refraction from postoperative refraction was compared among the ocular biometry devices.

Results

Axial lengths were 23.08 ± 0.62 mm, 23.09 ± 0.62 mm, and 22.99 ± 0.62 mm measured by AL scan®, IOL master®, and ultrasound, respectively. Axial length measured by ultrasound was statistically significantly shorter than AL scan® and IOL master® (p < 0.001, p < 0.001, respectively). The anterior chamber depth and keratometry were 3.11 ± 0.06 mm and 44.82 ± 1.34 D measured by AL scan®, and 3.13 ± 0.06 mm and 44.85 ± 1.26 D measured by IOL master®, respectively. The differences of anterior chamber depth and keratometry between the 2 devices were not statistically significant (p = 0.226, p = 0.331, respectively). The mean absolute prediction errors were 0.44 ± 0.35 D, 0.40 ± 0.34 D, and 0.39 ± 0.30 D in AL-Scan®, IOL master® and ultrasound, respectively, and were not statistically significantly different (p = 0.843, p = 0.847, p = 1.000, respectively).

Conclusions

The ocular biometric measurements and prediction of postoperative refraction using AL-Scan® were as accurate as IOL master® and ultrasound.

Keywords: AL-Scan®R, Axial length, IOL master®R, Partial coherence interferometry

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Figure 1.

Bland-Altman plot of axial length between AL scan® and IOL master® (A), and A-scan (B) (95% limits of agreement for axial length difference: AL scan® -IOL master® [-0.049, 0.036]; AL scan® - A-scan [0.048, 0.141]).

Figure 2.

Bland-Altman plot of anterior chamber depth between AL scan® and IOL master® (95% limits of agreement for axial length difference: AL scan® - IOL master® [-0.34, 0.28]).

Figure 3.

Bland-Altman plot of keratometry between AL scan® and IOL master® (A), and Auto refractive keratometry (ARK) (B) (95% limits of agreement for axial length difference: AL scan® -IOL master® [-0.49, 0.41]; AL scan® - ARK [-0.44, 0.38]).

Table 1.

Demographics and Biometry measurements by AL scan®, IOL master®, A-scan

	AL scan®	IOL master®	A-scan
Age (years)	68.7 ± 9.1 (51-95)	−	−
Sex (M/F)	40 (18/22)	−	−
AL^* (mm)	23.08 ± 0.62	23.09 ± 0.62	22.99 ± 0.62
ACD^† (mm)	3.11 ± 0.06	3.13 ± 0.06	−
K 2.4^‡ mm (diopter)	44.82 ± 1.34	44.85 ± 1.26	−
K 3.0^‡ mm (diopter)	44.75 ± 1.34	−	−

Values are presented as mean ± SD.

^* Axial length;

^† Anterior chamber depth;

^‡ Keratometry was calculated at corneal radius 2.4 mm and 3.0 mm.

Table 2.

Comparison of Absolute prediction error among AL scan®, IOL master®, A-scan

	Prediction error (diopter)			Number of eyes (%)
	Absolute PE^*	Range	0.5D	1.0D	1.5D	2.0D
AL scan®	0.44 ± 0.35	0.04-1.59	22^†,‡(55%)	38 (95%)	39 (97.5%)	40 (100%)
IOL master®	0.40 ± 0.34	0.03-1.58	27 (67.5%)	39 (97.5%)	39 (97.5%)	40 (100%)
A-scan	0.40 ± 0.30	0.01-1.17	29 (72.5%)	38 (95%)	40 (100%)	40 (100%)

Values are presented as mean ± SD.

^* Prediction error;

^† Denotes significant difference compared to A-scan group (ANOVA, p < 0.05);

^‡ Denotes significant difference compared to IOL master® group (ANOVA, p < 0.05).

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