Sung Jin Park; Sung Hyup Lim; Ho Young Lee

doi:10.3341/jkos.2014.55.7.984

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Park, Lim, and Lee: Comparative Analysis of Corneal Refractive Power Measured with AL-Scan®, Autokeratometer, and Pentacam®

Original Article

J Korean Ophthalmol Soc 2014;55(7):984-990.

Published online: 30 August 2014

DOI: https://doi.org/10.3341/jkos.2014.55.7.984

Comparative Analysis of Corneal Refractive Power Measured with AL-Scan®, Autokeratometer, and Pentacam®

Sung Jin Park, MD¹, Sung Hyup Lim, MD¹, Ho Young Lee, MD^2,

¹Department of Ophthalmology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea

²Shinsegae Eye Clinic, Busan, Korea

Address reprint requests to Ho Young Lee, MD, Shinsegae Eye Clinic, #783-1 Gaya-daero, Busanjin-gu, Busan 614-849, Korea, Tel: 82-51-808-8288, Fax: 82-51-808-8238 E-mail: happytriad@gmail.com

Received 25 January 2014 Revised 28 March 2014 Accepted 24 June 2014

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 investigate clinical availability of AL-Scan® (Nidek, Gamagori, Japan) by comparing corneal refractive power with AL-Scan™, Autokeratometer™ (Topcon KR-1, Tokyo, Japan) and Pentacam™ (Oculus, Wetzlar, Germany) devices.

Methods

Seventy-one patients (142 eyes) who visited our hospital for refractive surgery were tested using AL-Scan®, Autokeratometer and Pentacam® and corneal refractive power was compared among devices.

Results

When comparing measurements with AL-Scan®, Autokeratometer and Pentacam®, the mean corneal refractive power was 43.37 ± 1.32 D (2.4 mm zone), 43.35 ± 1.32 D (3.3 mm zone), 43.36 ± 1.35 D, and 43.35 ± 1.36 D respectively and showed no significant differences. Corneal refractive power had strongly positive linear correlation (p < 0.001) and Bland-Altman plots showed high degree of agreement among AL-Scan®, Autokeratometer and Pentacam® devices.

Conclusions

Because measuring ocular biometry with AL-Scan including axial length, intraocular lens power calculation and topography simultaneously is possible, clinical use is convenient. Corneal refractive power was not different when compared with autokeratometer and Pentacam® devices, thus, AL-Scan® can be used in the clinical environment.

Keywords: AL-Scan®, Autokeratometer, Corneal refractive power, Pentacam®

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Figure 1.

Pearson correlation of corneal refractive power (K) measured with AL-Scan®, Autokeratometer and Pentacam®.

Figure 2.

Bland-Altman plots of corneal refractive power (K) measured with AL-Scan®, Autokeratometer and Pentacam®.

Table 1.

Results of corneal refractive power (K) of AL-Scan®, Autokeratometer and Pentacam®

Corneal refractive power (K)	AL-Scan®		Autokeratometer	Pentacam®
Corneal refractive power (K)	2.4 mm	3.0 mm	3.0 mm	3.0 mm
Kmean (diopter)	43.37 ± 1.32	43.35 ± 1.32	43.36 ± 1.35^*	43.35 ± 1.36^*
K1 (diopter)	42.70 ± 1.20	42.69 ± 1.21	42.72 ± 1.23^*	42.63 ± 1.24^*
K2 (diopter)	44.04 ± 1.52	44.01 ± 1.52	44.00 ± 1.56^*	44.06 ± 1.58^*

Values are presented as mean ± SD.

^* Corneal refractive power (K) with Autokeratometer and Pentacam® was measured only 3.0 mm zone.

Table 2.

Comparison of mean corneal refractive power (K) among devices

Devices		p-value
Autokeratometer^*	AL-Scan® (2.4 mm zone)	0.595^†
	AL-Scan® (3.3 mm zone)	0.450^†
	Pentacam®^*	0.349^†
AL-Scan® (2.4 mm zone)	AL-Scan® (3.3 mm zone)	0.009^†
AL-Scan® (2.4 mm zone)	Pentacam®^*	0.199^†
AL-Scan® (3.3 mm zone)	Pentacam®^*	0.794^†

^* Corneal refractive power (K) with Autokeratometer and Pentacam® was measured only 3.0 mm zone;

^† Paired t-test.

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