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Repeatability, Reproducibility and Agreement of Central Corneal Thickness Measurements by Two Noncontact Pachymetry Devices



This study was designed to assess the repeatability, reproducibility, and agreement of Noncontact Pachymetry (NPC) (Topcan TRK-2P) and the non-contact optical low coherence reflectometer (Lenstar LS 900) devices for measuring Central Corneal Thickness (CCT) of healthy corneas. A total of 82 healthy volunteers were evaluated. The first observer used both the TopconTRK-2P and Lenstar 900 devices while the second observer only used the TopconTRK-2P for the measurements. The measurements with either device were repeated three times for each patient, consecutively. The central corneal thickness measurements with the Topcon TRK-2P revealed mean ± Standard Deviation (SD) values of 553.1 ± 36.1 micrometer (µm) for the first observer and 552.3 ± 35.9µm for the second observer and the mean ± SD of CCT was 537.3 ± 34.8µm with the Lenstar 900. The difference between the CCT measurements of the observers using the Topcon TRK-2P (P = 0.142) was insignificant. However, significantly lower measurements were found with the Lenstar 900 compared with the Topcon TRK-2P (P ˂ 0.001). The central corneal thickness measurements obtained by the Topcon TRK-2P were found to have high repeatability for both observers with a lower SD, less than 1% Coefficient of Variation (CV) and higher than 0.99 Intra-Class Correlation Coefficient (ICC) (Observer 1: 3.77 SD, 0.68 CV and 0.995 ICC; the second observer: 3.58 SD, 0.65 CV and 0.995 ICC). There was an excellent inter-observer reproducibility between the two observers for Topcon TRK-2P with 2.71 SD, 0.49 CV, and 0.994 ICC. The Bland-Altman plot showed high agreement between the two devices. These results suggest that the TopconTRK-2P is a reliable device for evaluating CCT in healthy corneas compared with Lenstar 900.


Kopplin LJ, Przepyszny K, Schmotzer B, Rudo K, Babineau DC, Patel SV, et al. Relationship of Fuchs endothelial corneal dystrophy severity to central corneal thickness. Arch Ophthalmol. 2012;130(4):433-9. doi: 10.1001/archopthalmol.2011.1626

1001/archophthalmol.2011.1626 pmid: 22491913

Hayashi K, Yoshida M, Manabe S, Hirata A. Cataract surgery in eyes with low corneal endothelial cell density. J Cataract Refract Surg. 2011;37(8):1419-25. doi: 10.1016/j.jcrs.2011.02.025 pmid: 21684110

Rabinowitz YS. Ectasia after laser in situ keratomileusis. Curr Opin Ophthalmol. 2006;17(5):421-6. doi: 10.1097/ 886.3a pmid: 16932057

Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach. Surv Ophthalmol. 2000;44(5):367-408. doi: 10.1016/s0039-6257(00)001 10-7 pmid: 10734239

Gordon MO, Beiser JA, Brandt JD, Heuer DK, Higginbotham EJ, Johnson CA, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120(6):714-20; discussion 829-30. pmid: 12049575

Taneri S, Zieske JD, Azar DT. Evolution, techniques, clinical outcomes, and pathophysiology of LASEK: review of the literature. Surv Ophthalmol. 2004;49(6):576-602. doi: 10.1016/j.survophthal.2004 .08.003 pmid: 15530945

Auffarth GU, Wang L, Volcker HE. Keratoconus evaluation using the Orbscan Topography System. J Cataract Refract Surg. 2000;26(2):222-8. doi: 10.1016/s0886-3350(99)00355-7 pmid: 10683789

Marsich MW, Bullimore MA. The repeatability of corneal thickness measures. Cornea. 2000;19(6):792-5. doi: 10.1097/00003226-200011000-00007 pmid: 11095052

Barkana Y, Gerber Y, Elbaz U, Schwartz S, Ken-Dror G, Avni I, et al. Central corneal thickness measurement with the Pentacam Scheimpflug system, optical low-coherence reflectometry pachymeter, and ultrasound pachymetry. J Cataract Refract Surg. 2005;31(9):1729-35. doi: 10.1016/j.jcrs.2005.03.058 pmid: 16246776

McLaren JW, Nau CB, Erie JC, Bourne WM. Corneal thickness measurement by confocal microscopy, ultrasound, and scanning slit methods. Am J Ophthalmol. 2004;137(6):1011-20. doi: 10.1016/j.ajo. 2004.01.049 pmid: 15183784

Prospero Ponce CM, Rocha KM, Smith SD, Krueger RR. Central and peripheral corneal thickness measured with optical coherence tomography, Scheimpflug imaging, and ultrasound pachymetry in normal, keratoconus-suspect, and post-laser in situ keratomileusis eyes. J Cataract Refract Surg. 2009;35(6):1055-62. doi: 10.1016/j.jcrs.2009.01.022 pmid: 19465292

Bjelos Roncevic M, Busic M, Cima I, Kuzmanovic Elabjer B, Bosnar D, Miletic 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(1):83-7. doi: 10.1007/s00417-010-1546-z pmid: 20981435

Beutelspacher SC, Serbecic N, Scheuerle AF. [Measurement of the central corneal thickness using optical reflectometry and ultrasound]. Klin Monbl Augenheilkd. 2011;228(9):815-8. doi: 10.1055/s-0029-1245776 pmid: 21432766

Beutelspacher SC, Serbecic N, Scheuerle AF. Assessment of central corneal thickness using OCT, ultrasound, optical low coherence reflectometry and Scheimpflug pachymetry. Eur J Ophthalmol. 2011;21(2):132-7. doi: 10.5301/ejo.2010.1093 pmid: 20872361

Simsek A, Bilak S, Guler M, Capkin M, Bilgin B, Reyhan AH. Comparison of Central Corneal Thickness Measurements Obtained by RTVue OCT, Lenstar, Sirius Topography, and Ultrasound Pachymetry in Healthy Subjects. Semin Ophthalmol. 2016;31(5):467-72. doi: 10.3109/08820538.2014.962173 pmid: 25412328

Bayhan HA, Bayhan SA, Muhafiz E, Can İ. Comparison of Anterior Segment Parameters with Optical Low Coherence Reflectometer and Combined Scheimpflug-Placido Disk Topographer. Glokom-Katarakt. 2013;8(2).

Bland JM, Altman DG. Agreed statistics: measurement method comparison. Anesthesiology. 2012;116(1):182-5. doi: 10.1097/ALN.0b013e31823d7 784 pmid: 22129533

Muller R, Buttner P. A critical discussion of intraclass correlation coefficients. Stat Med. 1994;13(23-24):2465-76. doi: 10.1002/sim.4780132310 pmid: 7701147

Gonul S, Koktekir BE, Bakbak B, Gedik S. Comparison of central corneal thickness measurements using optical low-coherence reflectometry, Fourier domain optical coherence tomography, and Scheimpflug camera. Arq Bras Oftalmol. 2014;77(6):345-50. doi: 10.5935/0004-2749.20140087 pmid: 25627178

Koktekir BE, Gedik S, Bakbak B. Comparison of Central Corneal Thickness Measurements With Optical Low-Coherence Reflectometry and Ultrasound Pachymetry and Reproducibility of Both Devices. Cornea. 2012;31(11):1278-81. doi: 10.1097/ICO.0b013e31823f 7701 pmid: 22262222

Huang HW, Hu FR, Wang IJ, Hou YC, Chen WL. Migration of limbal melanocytes onto the central cornea after ocular surface reconstruction: an in vivo confocal microscopic case report. Cornea. 2010;29(2):204-6. doi: 10.1097/ICO.0b013e3181a165 65 pmid: 19770728

Borrego-Sanz L, Saenz-Frances F, Bermudez-Vallecilla M, Morales-Fernandez L, Martinez-de-la-Casa JM, Santos-Bueso E, et al. Agreement between central corneal thickness measured using Pentacam, ultrasound pachymetry, specular microscopy and optic biometer Lenstar LS 900 and the influence of intraocular pressure. Ophthalmologica. 2014;231(4):226-35. doi: 10.1159/000356724 pmid: 24642898

Tai LY, Khaw KW, Ng CM, Subrayan V. Central corneal thickness measurements with different imaging devices and ultrasound pachymetry. Cornea. 2013;32(6):766-71. doi: 10.1097/ICO.0b013e3182699 38d pmid: 23095499

Bayhan HA, Aslan Bayhan S, Can I. Comparison of central corneal thickness measurements with three new optical devices and a standard ultrasonic pachymeter. Int J Ophthalmol. 2014;7(2):302-8. doi: 10.3980/j.issn.2222-3959.2014.02.19 pmid: 24790874

Schiano Lomoriello D, Lombardo M, Tranchina L, Oddone F, Serrao S, Ducoli P. Repeatability of intra-ocular pressure and central corneal thickness measurements provided by a non-contact method of tonometry and pachymetry. Graefes Arch Clin Exp Ophthalmol. 2011;249(3):429-34. doi: 10.1007/s0041 7-010-1550-3 pmid: 20981434

Wells M, Wu N, Kokkinakis J, Sutton G. Correlation of central corneal thickness measurements using Topcon TRK-1P, Zeiss Visante AS-OCT and DGH Pachmate 55 handheld ultrasonic pachymeter. Clin Exp Optom. 2013;96(4):385-7. doi: 10.1111/cxo.12013 pmid: 23336739

Gursoy H, Sahin A, Basmak H, Ozer A, Yildirim N, Colak E. Lenstar versus ultrasound for ocular biometry in a pediatric population. Optom Vis Sci. 2011;88(8):912-9. doi: 10.1097/OPX.0b013e31821cc4d6 pmid: 21552178

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