The Intra and Inter-Examiner Repeatability of Corneal Parameters Obtained by GALILEI TM in Normal Subjects

Young-Eun Lee; Roo Min Jun

doi:10.3341/jkos.2009.50.11.1611

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Lee and Jun: The Intra and Inter-Examiner Repeatability of Corneal Parameters Obtained by GALILEI TM in Normal Subjects

Original Article

J Korean Ophthalmol Soc 2009;50(11):1611-1616.

Published online: 31 August 2009

DOI: https://doi.org/10.3341/jkos.2009.50.11.1611

The Intra and Inter-Examiner Repeatability of Corneal Parameters Obtained by GALILEI ^TM in Normal Subjects

Young-Eun Lee, MD, Roo Min Jun, MD

Department of Ophthalmology, School of Medicine, Ewha Womans University, Seoul, Korea

Address reprint requests to Roo Min Jun, MD, Department of Ophthalmology, School of Medicine Ewha Womans University, Mokdong Hospital #911-1 Mok-dong, Yangcheon-gu, Seoul 158-710, Korea Tel: 82-2-2650-5154, Fax: 82-2-2654-4334, E-mail: jrmoph@ewha.ac.kr

Received 10 February 2009 Accepted 4 August 2009

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 verify the intra-examiner and inter-examiner repeatability of corneal parameters obtained by GALILEI^TM.

Methods

Corneal parameters were measured by GALILEI in 44 eyes of 28 healthy subjects. One examiner took the measurements twice and intra-examiner repeatability was evaluated. Another examiner measured the corneal parameters once again and inter-examiner repeatability was evaluated.

Results

Intra-examiner and inter-examiner repeatability were high for corneal parameters including average SimK, flat SimK, steep SimK, average posterior corneal keratometry, flat posterior corneal keratometry, steep posterior corneal keratometry, central corneal thickness, total corneal volume, and average pupil diameter but low for limbus-to-limbus diameter (nasal-temporal and superior-inferior).

Conclusions

Anterior and posterior corneal parameters of GALILEI showed good intra-examiner and inter-examiner repeatability. However, limbus-to-limbus diameter showed poor intra-examiner and inter-examiner repeatability. GALILEI can be useful in clinical applications with special consideration when measuring the limbus-to-limbus diameter.

Keywords: Cornea, GALILEI, Repeatability, Topography

References

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Figure 1.

Scattergram showing intra- (A) and inter-examiner (B) repeatability of SimKavg.

Figure 2.

Scattergram showing intra- (A) and inter-examiner (B) repeatability of limbus to limbus diameter (nasal – temporal).

Table 1.

Patient demographics

Number of eyes	44
Male: female	8:20
Mean age (years)	28.1 ± 4.12 (22.0∼38.0)
Refractive error (diopter)	−1.84 ± 1.65 (−8.0∼+3.0)

Table 2.

Intra-examiner repeatability (Guttman split-half points are given for each parameters measured)

Parameters		Mean± SD	Guttman half split points
SimK (D)	Sim _avg^*	43.63±1.374	0.993
	Sim_f^†	42.96±1.311	0.982
	Sim _s^‡	44.27±1.500	0.991
Posterior corneal powers (D)	K _avg^§	−6.410±0.283	0.969
	K _f^∏	−6.180±0.380	0.949
	K _s^#	−6.640±0.266	0.863
Central corneal thickness (μm)	CCT^**	560.8±28.84	0.993
Limbus to limbus diameter (mm)	Nasal-temporal	11.70±1.198	0.137
	Superior-inferior	11.66±1.189	0.469
Total corneal volume (mm³)		34.16±1.766	0.933
Pupil average diameter (mm)		2.801±0.566	0.918

^*Sim _avg=average SimK

^†Sim _f=flat SimK

^‡Sim _s=steep SimK

^§K _avg=posterior average corneal keratometry

^∏K _f=posterior flat corneal keratometry

^#K_s=posterior steep corneal keratometry

^**CCT=central corneal thickness.

Table 3.

Inter-examiner repeatability (Guttman split-half points are given for each parameters measured)

Parameters		Mean± SD	Guttman half split points
SimK (D)	Sim _avg^*	43.79±1.508	0.975
	Sim _f^†	43.03±1.355	0.990
	Sim _s^‡	44.55±1.780	0.935
Posterior corneal powers (D)	K _avg^§	−6.330±0.294	0.802
	K _f^∏	−6.170±0.367	0.771
	K _s^#	−6.630±0.302	0.773
Central corneal thickness (μm)	CCT^**	560.4±29.18	0.990
Limbus to limbus diameter (mm)	Nasal-temporal	11.59±1.156	0.077
	Superior-inferior	11.58±1.215	0.434
Total corneal volume (mm³)		33.37±2.591	0.809
Pupil average diameter (mm)		2.845±0.602	0.962