Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness

Kelechi C Ogbuehi, Uchechukwu L Osuagwu, Kelechi C Ogbuehi, Uchechukwu L Osuagwu

Abstract

Background: The purpose of this study was to assess the repeatability and limits of agreement of corneal thickness values measured by a high-frequency ultrasound (Artemis-2), hand-held ultrasound pachymeter (DGH-500) and a specular microscope (SP-3000P).

Methods: Central corneal thickness (CCT) was analyzed in this prospective randomized study that included 32 patients (18 men and 14 women) aged 21-24 years. Measurements were obtained in two sessions, one week apart, by two examiners with three devices in a randomized order. Nine measurements were taken (three with each device) on one randomly selected eye of each patient in each measurement session. The coefficient of repeatability and interobserver reproducibility for the values of each method were calculated. The limits of agreement between techniques were also evaluated.

Results: There were no significant differences in CCT values between sessions for each of the three devices (P > 0.05). The repeatability coefficients for the Artemis-2 (±8 μm/±9 μm) were superior to those of the SP-3000P (±9 μm/±11 μm) and DGH 500 (±12 μm/±12 μm) in session 1/session 2 respectively, while the interobserver reproducibility index (differences between session 1 and session 2) was superior for the SP-3000P (±17 μm) with respect to DHG-500 (±29 μm) and the Artemis-2 (±31 μm). In session 1 and session 2, the limits of agreement between the techniques were 35 μm to -31 μm and 34 to -20 μm, respectively, for DGH-500 versus Artemis-2, 73 μm to 3 μm and 60 μm to 9 μm for Artemis-2 versus SP-3000P, and 58 μm to 22 μm and 72 μm to 10 μm for DGH-500 versus SP-3000P comparisons. The DGH-500 and Artemis-2 gave similar values (P > 0.05) in both sessions, but both (Artemis-2 and DGH-500) values were significantly greater than that of the SP-3000P (P < 0.05) in both sessions.

Conclusion: Repeatability was comparably good for the three techniques. However, interobserver reproducibility was approximately twice as good with the SP-3000P compared with the other two devices. The Artemis-2 CCT values consistently agreed with the DGH-500 and less so with the SP-3000P. The Artemis-2 provided CCT values that were, on average, 38 μm and 34 μm greater than that of the SP-3000P in session 1 and session 2, respectively.

Keywords: Artemis-2 ultrasound; SP-3000P noncontact specular microscopy; cornea thickness; hand-held ultrasound; reproducibility.

Figures

Figure 1
Figure 1
Bland-Altman plot of mean difference in central corneal thickness measurements between Artemis-2 and SP-3000P noncontact specular microscope against their mean in session 1 and session 2. Notes: Mean difference in session 1, P < 0.001; session 2, P < 0.001. Abbreviations: CCT, central corneal thickness; CI, confidence interval.
Figure 2
Figure 2
Bland-Altman plot of mean difference in central corneal thickness measurements between ultrasound pachymetry and Artemis-2 against their mean in session 1 and session 2. Notes: Mean difference in session 1, P > 0.05; session 2, P > 0.05. Abbreviations: CCT, central corneal thickness; CI, confidence interval.
Figure 3
Figure 3
Bland-Altman plot of mean difference in central corneal thickness measurements between ultrasound pachymetry and SP-3000P noncontact specular microscope against their mean in session 1 and session 2. Notes: Mean difference in session 1, P < 0.001; session 2, P < 0.001. Abbreviations: CCT, central corneal thickness; CI, confidence interval.

References

    1. Zhao MH, Zou J, Wang WQ, Li J. Comparison of central corneal thickness as measured by non-contact specular microscopy and ultrasound pachymetry before and post LASIK. Clin Experiment Ophthalmol. 2007;35:818–823.
    1. Konstantopoulos A, Hossain P, Anderson DF. Recent advances in ophthalmic anterior segment imaging: a new era for ophthalmic diagnosis. Br J Ophthalmol. 2007;91:551–557.
    1. Paul T, Lim M, Starr CE, Lloyd HO, Coleman DJ, Silverman RH. Central corneal thickness as measured by Orbscan II, ultrasound pachymeter and Artemis-2. J Cataract Refract Surg. 2008;34:1906–1912.
    1. Ou RJ, Shaw EL, Glasgow BJ. Keratectasia after laser in situ keratomileusis (LASIK): evaluation of the calculated residual stromal bed thickness. Am J Ophthalmol. 2002;134:771–773.
    1. Kwon RO, Price MO, Price FW, Jr, Ambrósio R, Jr, Belin MW. Pentacam characterization of corneas with Fuch dystrophy treated with Descement membrane endothelial keratoplasty. J Cataract Refract Surg. 2010;26:972–979.
    1. Martin R, de Juan V, Rodríguez G, Cuadrado R, Fernandez I. Measurement of corneal swelling variations without removal of the contact lens during extended wear. Invest Ophthalmol Vis Sci. 2007;48:3043–3050.
    1. Gordon MO, Beiser JA, Brandt JD, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open angle glaucoma. Arch Ophthalmol. 2002;120:714–720.
    1. Whictacre MM, Stein RA. Sources of error with the use of Goldmann type tonometers. Surv Ophthalmol. 1993;38:1–30.
    1. Korah S, Thomas R, Muliyil J. Comparison of optical and ultrasound pachymetry. Indian J Ophthalmol. 2000;48:279–283.
    1. Francisco L, Fernández-Sánchez V, López-Gil N, Cerviño A, Montés-Micó R. Comparison of partial coherence interferometry and ultrasound for anterior segment biometry. J Cataract Refract Surg. 2009;35:324–329.
    1. Marsich MW, Bullimore M. Repeatability of corneal thickness measures. Cornea. 2000;19:792–795.
    1. Kawana K, Miyata K, Tokunaga T, Kiuchi T, Hiraoka T, Oshika T. Central corneal thickness measurements using Orbscan II scanning slit topography, noncontact specular microscopy, and ultrasonic pachymetry in eyes with keratoconus. Cornea. 2005;24:967–971.
    1. Avitabile T, Franco L, Ortisi E, et al. Keratoconus staging: a computer-assisted ultra biomicroscopic method compared with videokerato-graphic analysis. Cornea. 2004;23:655–660.
    1. Bovelle R, Kaufman SC, Thompson HW, Hamano H. Corneal thickness measurements with the Topcon SP-2000P specular microscope and an ultrasound pachymeter. Arch Ophthalmol. 1999;117:868–870.
    1. Liu Z, Huang AJ, Pflugfelder SC. Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system. Br J Ophthalmol. 1999;83:774–778.
    1. Rainer G, Petternel V, Findl O, et al. Comparison of ultrasound pachymetry and partial coherence interferometry in the measurement of central corneal thickness. J Cataract Refract Surg. 2002;28:2142–2145.
    1. Reinstein DZ, Archer TJ, Gobbe M, Silverman RH, Coleman DJ. Repeatability of layered corneal pachymetry with the Artemis very high-frequency digital ultrasound arc scanner. J Refract Surg. 2010;26:646–659.
    1. O’Donnell C, Maldonado-Codina C. Agreement and repeatability of central thickness measurement in normal corneas using ultrasound pachymetry and the Oculus Pentacam. Cornea. 2005;24:920–924.
    1. Ceylan OM, Turk A, Erdurman C, et al. Comparison of Oculus Pentacam and Stratus optical coherence tomography for measurement of central corneal thickness. Cornea. 2011;30:670–674.
    1. Reinstein DZ, Archer TJ, Silverman RH, Coleman DJ. Accuracy, repeatability, and reproducibility of Artemis very high-frequency digital ultrasound arc-scan lateral dimension measurements. J Cataract Refract Surg. 2006;32:1799–1802.
    1. Bland JM, Altman DG. Measurement error. BMJ. 1996;313:744.
    1. Lattimore MR, Jr, Kaupp S, Schallhorn S, Lewis R., IV Orbscan pachymetry: implications of a repeated measures and diurnal variation analysis. Ophthalmology. 1999;106:977–981.
    1. British Standards Institution. Precision of Test Methods 1: Guide for the Determination and Reproducibility for a Standard Test Method (BS 597, Part 1) London, UK: British Standards Institution; 1975.
    1. Bland JM, Altman DG. Agreement between methods of measurement with multiple observations per individual. J Biopharm Stat. 2007;17:571–582.
    1. Bjeloš Rončević M, Bušić M, Cima I, Kuzmanović Elabjer B, Bosnar D, Miletić D. Intraobserver and interobserver repeatability of ocular components measurement in cataract eyes using a new optical low coherence reflectometer. Graefes Arch Clin Exp Ophthalmol. 2011;249:83–87.
    1. Ogbuehi KC, Almubrad TM. Repeatability of central corneal thickness measurements measured with the Topcon SP-2000P specular microscope. Graefes Arch Clin Exp Ophthalmol. 2005;243:798–802.
    1. Módis L, Jr, Langenbucher A, Seitz B. Corneal thickness measurements with contact and noncontact specular microscopic and ultrasonic pachymetry. Am J Ophthalmol. 2001;132:517–521.
    1. Suzuki S, Oshika T, Oki K, et al. Corneal thickness measurements: scanning slit corneal topography and noncontact specular microscope versus ultrasonic pachymetry. J Cataract Refract Surg. 2003;29:1313–1318.
    1. González-Pérez J, González-Méijiome JM, Ares MTR, Parafita MÁ. Central corneal thickness measured with three optical devices and ultrasound pachometry. Eye Contact Lens. 2011;37:66–70.
    1. Al-Aqeel S, Al-Muammar AM. Comparison of central corneal thickness measurements by Pentacam, noncontact specular microscope, and ultrasound pachymetry in normal and post-LASIK eyes. Saudi J Ophthalmol. 2009;23:181–187.
    1. Kawana K, Tokunaga T, Miyata K, Okamoto F, Kiuchi T, Oshika T. Comparison of corneal thickness measurements using Orbscan II, noncontact specular microscopy, and ultrasonic pachymetry in eyes after laser in situ keratomileusis. Br J Ophthalmol. 2004;88:466–468.
    1. Reinstein DZ, Archer MA, Gobbe M. Repeatability of intraoperative central corneal and residual stromal thickness measurement using a handheld ultrasound pachymeter. J Cataract Refract Surg. 2012;38:278–282.
    1. Lackner B, Schmidinger G, Pieh S, Funovics MA, Skorpik C. Repeatability and reproducibility of central corneal thickness measurement with Pentacam, Orbscan, and ultrasound. Optom Vis Sci. 2005;82:892–899.
    1. de Sanctis U, Missolungi A, Mutani B, Richiardi L, Grignolo FM. Reproducibility and repeatability of central corneal thickness measurement in keratoconus using the rotating Scheimpflug camera and ultrasound pachymetry. Am J Ophthalmol. 2007;144:712–718.

Source: PubMed

Sponzoři a spolupracovníci

Zdravotní podmínky

Drogové intervence

3
Předplatit