Comparison of Anterior Segment Measurements between Dual and Single Scheimpflug Camera

Youngju An; Hyojin Kim; Choun-Ki Joo

doi:10.3341/jkos.2016.57.7.1056

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An, Kim, and Joo: Comparison of Anterior Segment Measurements between Dual and Single Scheimpflug Camera

Original Article

J Korean Ophthalmol Soc 2016;57(7):1056-1062.

Published online: 25 September 2016

DOI: https://doi.org/10.3341/jkos.2016.57.7.1056

Comparison of Anterior Segment Measurements between Dual and Single Scheimpflug Camera

Youngju An, MPH¹, Hyojin Kim, MPH, PhD², Choun-Ki Joo, MD, PhD^1,^3,

¹Catholic Institute of Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Korea

²Division of Health Science, Baekseok University, Cheonan, Korea

³Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Korea

Address reprint requests to Choun-Ki Joo, MD, PhD Department of Ophthalmology, The Catholic University of Korea Seoul St. Mary's Hospital, #222 Banpo-daero, Seocho-gu, Seoul 06591, Korea Tel: 82-2-2258-1188, Fax: 82-2-599-7405 E-mail: ckjoo@catholic.ac.kr

Received 3 December 2015 Accepted 23 May 2016

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 assess the degree of agreement of two rotating Scheimpflug cameras, Galilei G6 and Pentacam HR, in measuring corneal refractive power (K), anterior chamber depth (ACD), and central corneal thickness (CCT).

Methods

Measurement agreement was assessed in 40 eyes of 40 outpatients at our hospital. Measurements of anterior and posterior corneal refractive power (K), ACD, and CCT were compared between the Galilei G6 and Pentacam HR.

Results

For Galilei G6 (4 mm), Pentacam HR (3 mm) and Pentacam HR (4 mm), the anterior corneal refractive powers (K) were 44.35 ± 1.38 D, 44.09 ± 1.32 D, and 44.12 ± 1.35 D, respectively, and the posterior corneal refractive powers (K) were 6.39 ±0.23 D, 6.45 ± 0.23 D, 6.45 ±0.22 D. The differences in the results were statistically significant. The average ACD measurements using Galilei G6 and Pentacam HR were 3.26 ± 0.42 mm and 3.17 ± 0.42 mm, respectively, and the average CCT measurements were 556.65 ± 30.12 µm and 553.78 ± 29.42 µm. The differences in the measurements were statistically significant. In addition, ACD 95% limits of agreement (LoA) between Galilei G6 and Pentacam HR were in the range of −0.14∼0.32 mm, and CCT 95% LoA were in the range of −12.54∼18.29 µm.

Conclusions

There were significant differences in measurements of anterior and posterior corneal refractive power (K), ACD, and CCT between the two cameras. Agreement analysis suggests that Galilei G6 and Pentacam HR should not be used interchangeably.

Keywords: Anterior chamber depth, Central corneal thickness, Corneal refractive power, Scheimpflug camera

References

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Figure 1.

Pearson correlation of Galilei G6 and Pentacam HR in anterior segment parameters. (A) Anterior mean keratometric diopter (K _mean) (Pentacam HR 3 mm), (B) Posterior K _mean (Pentacam HR 3 mm), (C) Anterior K _mean (Pentacam HR 4 mm), (D) Posterior K _mean (Pentacam HR 4 mm), (E) anterior chamber depth (ACD), (F) central corneal thickness (CCT). K = keratometric diopter.

Figure 2.

Bland-Altman plots of Galilei G6 and Pentacam HR in anterior segment parameters. (A) Anterior mean keratometric diopter (K _mean) (Pentacam HR 3 mm), (B) Posterior K _mean (Pentacam HR 3 mm), (C) Anterior K _mean (Pentacam HR 4 mm), (D) Posterior K _mean (Pentacam HR 4 mm), (E) anterior chamber depth (ACD), (F) central corneal thickness (CCT). K = keratometric diopter.

Table 1.

Patient demographics

Parameter	Data
No. of eyes (patients)	40 (40)
Age (years)	62.28 ± 10.20
Sex (male:female)	13:27
Laterality (right:left)	17:23
Spherical equivalent (D)	–0.12 ± 2.22

Values are presented as mean ± SD.

Table 2.

Comparison of corneal refractive power (K) measured by Galilei G6 and Pentacam HR

	Anterior corneal surface			Posterior corneal surface
	K_mean (D)	Difference (D)	p-value^*	K_mean (D)	Difference (D)	p-value^*
Galilei G6 (4 mm)	44.35 ± 1.38			6.39 ± 0.23
Pentacam HR (3 mm)	44.09 ± 1.32	0.26 ± 0.27^†	<0.001	6.45 ± 0.23	–0.06 ± 0.10^†	<0.001
Pentacam HR (4 mm)	44.12 ± 1.35	0.23 ± 0.23^‡	<0.001	6.45 ± 0.22	–0.06 ± 0.13^‡	0.004

Values are presented as mean ± SD.

^* Paired t-test

^† Galilei G6 (4 mm) vs. Pentacam HR (3 mm)

^‡ Galilei G6 (4 mm) vs. Pentacam HR (4 mm).

Table 3.

Comparison of anterior chamber depth (ACD) and central corneal thickness (CCT) measured by Galilei G6 and Pentacam HR

	Galilei G6	Pentacam HR	Difference	p-value^*
ACD (mm)	3.26 ± 0.42	3.17 ± 0.42	0.09 ± 0.12	<0.001
CCT (µm)	556.65 ± 30.12	553.78 ± 29.42	–2.88 ± 7.71	0.023

Values are presented as mean ± SD.

^* Paired t-test.

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