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Lee, Hwang, Kim, Lee, Yoo, Kim, and Lee: Comparison and Repeatability of Anterior Segment Parameters Obtained by Galilei and Slit-lamp Optical Coherence Tomography
Original Article

J Korean Ophthalmol Soc 2011;52(1):53-59.

Published online: 7 September 2011

DOI: https://doi.org/10.3341/jkos.2011.52.1.53

Comparison and Repeatability of Anterior Segment Parameters Obtained by Galilei and Slit-lamp Optical Coherence Tomography

Won Hyuk Lee, MD1, Young Hoon Hwang, MD2, Se Jong Kim, MD2, Sang Mok Lee, MD, PhD2, Chungkwon Yoo, MD, PhD3, Yong Yeon Kim, MD, PhD3, Joo Hwa Lee, MD, PhD1

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

2Department of Ophthalmology, The Armed Forces Capital Hospital, Seongnam, Korea

3Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea

Address reprint requests to Young Hoon Hwang, MD Department of Ophthalmology, The Armed Forces Capital Hospital #13-4 Yul-dong, Bundang-gu, Seongnam 463-040, Korea Tel: 82-31-725-6270, Fax: 82-31-706-0987, E-mail: brainh@hanmail.net

Received 15 June 2010       Revised 26 September 2010       Accepted 9 December 2010

Copyright © 2011 Korean Ophthalmological Society

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 evaluate the repeatability and comparability of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements obtained by Galilei dual Scheimpflug analyzer (Ziemer, Port, Switzerland) and slit-lamp optical coherence tomography (SL-OCT; Heidelberg Engineering, Dossenheim, Germany).

Methods

ACD and CCT were measured by Galilei and SL-OCT in 68 eyes of 68 healthy young subjects. Each measurement was performed 3 times by a single examiner, and the repeatability of 3 consecutive measurements was analyzed. ACD and CCT measurements were compared between the 2 devices.

Results

Both Galilei and SL-OCT showed high repeatability (ICCs ≥ 0.994) for ACD and CCT measurements. The mean ACD and CCT measured by Galilei were greater than SL-OCT measurements by 0.11 ± 0.09 mm and 14.01 ± 7.38 μ m, respectively. The 95% limit of agreement values for ACD and CCT measurements were 0.36 mm, 27.66 μ m, respectively, and were highly correlated (correlation coefficients ≥ 0.89, p < 0.001).

Conclusions

Although the repeatability of each device was high, ACD and CCT obtained by Galilei and SL-OCT were significantly different. These differences should be considered when interpreting ACD and CCT measurements obtained by the 2 devices.

Keywords: Anterior chamber depth, Central corneal thickness, Galilei dual Scheimpflug analyzer, Slit-lamp optical coherence tomography

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Figure 1.
Scatter plot and Bland-Altman plot of anterior chamber depth (ACD) measurement by Galilei and slit-lamp optical coherence tomography (SL-OCT).
jkos-52-53f1.tif
Figure 2.
Scatter plot and Bland-Altman plot of central corneal thickness (CCT) measurement by Galilei and slit-lamp optical coherence tomography (SL-OCT).
jkos-52-53f2.tif
Table 1.
Comparison of anterior chamber depth (ACD) and central corneal thickness (CCT) measured by Galilei and slit-lamp optical coherence tomography (SL-OCT) among the three groups
Moderate to high myopia group (n = 23) Low myopia group (n = 33) Non myopic group (n = 12) P-value Post hoc
Galilei
  ACD (mm) 3.41 ± 0.19 3.33 ± 0.18 3.15 ± 0.20 0.001 MM/LM > NM (p = 0.001 for MM>NM, 0.023 for LM>NM)
  CCT (μ m) 547.87 ± 19.54 558.65 ± 24.20 569.25 ± 41.27 0.077
SL OCT
  ACD (mm) 3.27 ± 0.18 3.22 ± 0.19 3.10 ± 0.14 0.030 MM > NM (p = 0.025)
  CCT (μ m) 525.80 ± 30.90 547.13 ± 24.86 555.58 ± 46.74 0.092

P-value: 1-way ANOVA; MM = moderate to high myopia group; LM = low myopia group; NM = non-myopic group; Post hoc=bonferroni post hot analysis.

Table 2.
Anterior chamber depth (ACD) and central corneal thickness (CCT) measurement repeatability of Galilei and slit-lamp optical coherence tomography (SL-OCT)
Galilei SL-OCT
ACD (mm)
  Mean ± SD 3.33 ± 0.20 3.22 ± 0.19
  R95 0.05 0.04
  CV % 0.58 0.45
  ICC (95% CI) 0.994 (0.991 to 0.996) 0.997 (0.995 to 0.998)
CCT (μ m)
  Mean ± SD 556.82 ± 27.34 544.90 ± 33.06
  R95 3.41 7.13
  CV % 0.22 0.47
  ICC (95% CI) 0.999 (0.998 to 0.999) 0.998 (0.996 to 0.999)

SD = standard deviation; R95: repeatability = Sw × 2.77 (95% of differences between 2 measures for the same subject would by expected to be less than this value); CV = coefficient of variation; ICC = intraclass correlation coefficient; CI = confidence interval.

Table 3.
Pair-wise comparison of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements obtained by Galilei and slit-lamp optical coherence tomography (SL-OCT)
Pairwise comparison Mean difference ± S * P-value P Pearson correlatio coefficient † P-value 95% limit of agreement
ACD (mm)
  Galilei SL OCT 0.11 ± 0.09 < 0.001 0.89 < 0.001 0.07 to 0.29
CCT (μ m)
  Galilei SL OCT 14.01 ± 7.38 < 0.001 0.98 < 0.001 1.67 to 29.33

SD = standard deviation.

* P-value = paired t test

† P-value = pearson correlation.

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