Galilei Corneal Tomography for Screening of Refractive Surgery Candidates: A Review of the Literature, Part II
Medical hypothesis discovery and innovation in ophthalmology,
Vol. 8 No. 3 (2019),
20 September 2019
,
Page 204-218
Abstract
Corneal topography is the most widely used technology for examining the anterior corneal surface. Scheimpflug imaging is a newer technique that allows for measurement of both the anterior and posterior corneal surface, which allows for three-dimensional reconstruction of the cornea. This is of particular interest and value in the field of cataract and refractive surgery. The Galilei camera is a commercially available dual Scheimpflug system that combines curvature data from Placido disc-based corneal topography with elevation data from Scheimpflug technology. The addition of Placido disc topography makes the Galilei unique from its more popular counterpart, the Pentacam, which was discussed in Part I. Compared to the Pentacam, and however, the Galilei analyzer is a newer system that has emerged as a valuable screening tool given its dual Scheimpflug capability. In the first article of this series, the authors summarized the refractive indices available on the Pentacam system with the purpose of identifying the best diagnostic parameters for keratoconus. Similarly, the purpose of this article is to summarize corneal surface indices available on the Galilei system and evaluate their use in screening of the refractive surgery candidate. Since post-operative keratectasia is still prevalent, this paper aims to identify the most clinically relevant indices that may be used in pre-operative evaluation.
References
Galilei G4 Operator Manual. Port, Switzerland: Zeimer Ophthalmic Systems AG; 2016.
Arce C. GALILEI: Map Interpretation Guide. Software V. Port. Switzerland: Zeimer Ophthalmic Systems AG; 2011.
Shetty R, Rao H, Khamar P, Sainani K, Vunnava K, Jayadev C, et al. Keratoconus Screening Indices and Their Diagnostic Ability to Distinguish Normal From Ectatic Corneas. Am J Ophthalmol. 2017;181:140-8. doi: 10.1016/j.ajo.2017. 06.031 pmid: 28687218
Feizi S, Yaseri M, Kheiri B. Predictive Ability of Galilei to Distinguish Subclinical Keratoconus and Keratoconus from Normal Corneas. J Ophthalmic Vis Res. 2016;11(1):8-16. doi: 10.4103/2008-322X.180707 pmid: 27195079
Smadja D, Touboul D, Cohen A, Doveh E, Santhiago MR, et al. Detection of subclinical keratoconus using an automated decision tree classification. Am J Ophthalmol. 2013;156(2):237-46 e1. doi: 10.1016/j.ajo.2013.03.034 pmid: 23746611
Demir S, Sonmez B, Yeter V, Ortak H. Comparison of normal and keratoconic corneas by Galilei Dual-Scheimpflug Analyzer. Cont Lens Anterior Eye. 2013;36(5):219-25. doi: 10. 1016/j.clae.2013.04.001 pmid: 23642799
Golan O, Hwang ES, Lang P, et al. Differences in Posterior Corneal Features Between Normal Corneas and Subclinical Keratoconus. J Refract Surg. 2018;34(10):664-70. doi: 10.3928/1081597X-20180823-02 pmid: 30296327
Arce C. Qualitative and quantitative analysis of aspheric symmetry and asymmetry on corneal surfaces. ASCRS Symposium and Congress; Boston: MA; 2010.
Golan O, Piccinini AL, Hwang ES, De Oca Gonzalez IM, Krauthammer M, Khandelwal SS, et al. Distinguishing Highly Asymmetric Keratoconus Eyes Using Dual Scheimpflug/Placido Analysis. Am J Ophthalmol. 2019;201:46-53. doi: 10.1016/ j.ajo.2019.01.023 pmid: 30721688
Bayraktar Bilen N, Hepsen IF, Arce CG. Correlation between visual function and refractive, topographic, pachymetric and aberrometric data in eyes with keratoconus. Int J Ophthalmol. 2016;9(8):1127-33. doi: 10.18240/ijo.2016.08.07 pmid: 27588266
Smadja D, Touboul D, Colin J. Comparative Evaluation of Elevation, Keratometric, Pachymetric and Wavefront Parameters in Normal Eyes, Subclinical Keratoconus and Keratoconus with a Dual Scheimpflug Analyzer. Int J Kerat Ect Cor Dis. 2012; 1(3): 158-166.
Schlegel Z, Hoang-Xuan T, Gatinel D. Comparison of and correlation between anterior and posterior corneal elevation maps in normal eyes and keratoconus-suspect eyes. J Cataract Refract Surg. 2008;34(5):789-95. doi: 10.1016/j.jcrs. 2007.12.036 pmid: 18471634
Pinero DP, Nieto JC, Lopez-Miguel A. Characterization of corneal structure in keratoconus. J Cataract Refract Surg. 2012;38(12):2167-83. doi: 10.1016/j.jcrs.2012.10.022 pmid: 23195256
de Sanctis U, Loiacono C, Richiardi L, Turco D, Mutani B, Grignolo FM. Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus. Ophthalmology. 2008;115(9):1534-9. doi: 10.1016/j.ophtha.2008.02.020 pmid: 18405974
Kamiya K, Ishii R, Shimizu K, Igarashi A. Evaluation of corneal elevation, pachymetry and keratometry in keratoconic eyes with respect to the stage of Amsler-Krumeich classification. Br J Ophthalmol. 2014;98(4):459-63. doi: 10.1136/bjophthalmol-2013-304132 pmid: 24457362
Saad A, Gatinel D. Topographic and tomographic properties of forme fruste keratoconus corneas. Invest Ophthalmol Vis Sci. 2010;51(11):5546-55. doi: 10.1167/iovs.10-5369 pmid: 20554609
Arbelaez MC, Versaci F, Vestri G, Barboni P, Savini G. Use of a support vector machine for keratoconus and subclinical keratoconus detection by topographic and tomographic data. Ophthalmology. 2012;119(11):2231-8. doi: 10.1016/j.ophtha. 2012.06.005 pmid: 22892148
Boyd S, Gutierrez A, McCulley J. Atlas and text of corneal pathology and surgery. Ciudad de Panamá: Highlights Medical Publishers. 2011.
Febbraro J-L, Khan H, Koch D. Surgical Correction of Astigmatism. Cham: Springer International Publishing; 2018.
Barbara A e. Controversies in the Management of Keratoconus. Cham: Springer International Publishing; 2019.
Twa M. Irregular Astigmatism: Diagnosis and Treatment. Optom Vis Sci. 2009;86(10):1209. doi: 10.1097/ OPX.0b013e3181bafce1
Hernandez-Camarena JC, Chirinos-Saldana P, Navas A, Ramirez-Miranda A, de la Mota A, Jimenez-Corona A, et al. Repeatability, reproducibility, and agreement between three different Scheimpflug systems in measuring corneal and anterior segment biometry. J Refract Surg. 2014;30(9):616-21. pmid: 25250418
McMahon TT, Szczotka-Flynn L, Barr JT, Anderson RJ, Slaughter ME, Lass JH, et al. A new method for grading the severity of keratoconus: the Keratoconus Severity Score (KSS). Cornea. 2006;25(7):794-800. doi: 10.1097/01.ico.0000226359. 26678.d1 pmid: 17068456
Bayhan HA, Aslan Bayhan S, Muhafiz E, Can I. Repeatability of aberrometric measurements in normal and keratoconus eyes using a new Scheimpflug-Placido topographer. J Cataract Refract Surg. 2014;40(2):269-75. doi: 10.1016/j.jcrs. 2013.07.046 pmid: 24368115
Xu Z, Li W, Jiang J, Zhuang X, Chen W, Peng M, et al. Characteristic of entire corneal topography and tomography for the detection of sub-clinical keratoconus with Zernike polynomials using Pentacam. Sci Rep. 2017;7(1):16486. doi: 10.1038/s41598-017-16568-y pmid: 29184086
Lakshminarayanan V, Fleck A. Zernike polynomials: a guide. Journal of Modern Optics. 2011;58(7):545-61. doi: 10. 1080/09500340.2011.554896
Gobbe M, Guillon M. Corneal wavefront aberration measurements to detect keratoconus patients. Cont Lens Anterior Eye. 2005;28(2):57-66. doi: 10.1016/j.clae.2004.12.001 pmid: 16318836
Buhren J, Kuhne C, Kohnen T. Defining subclinical keratoconus using corneal first-surface higher-order aberrations. Am J Ophthalmol. 2007;143(3):381-9. doi: 10.1016/ j.ajo.2006.11.062 pmid: 17317387
L Alió J, H Shabayek M. Corneal Higher Order Aberrations: A Method to Grade Keratoconus. Journal of Refractive Surgery. 2006;22(6):539-45. doi: 10.3928/1081-597x-20060601-05
Barbero S, Marcos S, Merayo-Lloves J, Moreno-Barriuso E. Validation of the estimation of corneal aberrations from videokeratography in keratoconus. J Refract Surg. 2002; 18(3):263-70. pmid: 12051382
Lim L, Wei RH, Chan WK, Tan DT. Evaluation of higher order ocular aberrations in patients with keratoconus. J Refract Surg. 2007;23(8):825-8. pmid: 17985803
Reddy JC, Rapuano CJ, Cater JR, Suri K, Nagra PK, Hammersmith KM. Comparative evaluation of dual Scheimpflug imaging parameters in keratoconus, early keratoconus, and normal eyes. J Cataract Refract Surg. 2014;40(4):582-92. doi: 10.1016/j.jcrs.2013.08.061 pmid: 24680519
Tellouck J, Touboul D, Santhiago MR, Tellouck L, Paya C, Smadja D. Evolution Profiles of Different Corneal Parameters in Progressive Keratoconus. Cornea. 2016;35(6):807-13. doi: 10.1097/ICO.0000000000000833 pmid: 27078004
Rabinowitz YS, Rasheed K. KISA% index: a quantitative videokeratography algorithm embodying minimal topographic criteria for diagnosing keratoconus. J Cataract Refract Surg. 1999;25(10):1327-35. doi: 10.1016/s0886-3350(99)00195-9 pmid: 10511930
Wilson SE, Lin DT, Klyce SD. Corneal topography of keratoconus. Cornea. 1991;10(1):2-8. pmid: 2019102
Maeda N, Klyce SD, Smolek MK. Comparison of methods for detecting keratoconus using videokeratography. Arch Ophthalmol. 1995;113(7):870-4. doi: 10.1001/archopht. 1995.01100070044023 pmid: 7605277
Mahmoud AM, Roberts CJ, Lembach RG, Twa MD, Herderick EE, McMahon TT, et al. CLMI: the cone location and magnitude index. Cornea. 2008;27(4):480-7. doi: 10.1097/ICO. 0b013e31816485d3 pmid: 18434854
Feizi S, Delfazayebaher S, Javadi MA, Karimian F, Ownagh V, Sadeghpour F. Mean Posterior Corneal Power and Astigmatism in Normal Versus Keratoconic Eyes. J Ophthalmic Vis Res. 2018;13(2):93-100. doi: 10.4103/jovr.jovr_19_17 pmid: 29719635
Kocamis SI, Cakmak HB, Cagil N, Toklu Y. Investigation of the Efficacy of the Cone Location and Magnitude Index in the Diagnosis of Keratoconus. Semin Ophthalmol. 2016;31(3):203-9. doi: 10.3109/08820538.2014.914234 pmid: 24840348
Maeda N, Klyce SD, Smolek MK, Thompson HW. Automated keratoconus screening with corneal topography analysis. Invest Ophthalmol Vis Sci. 1994;35(6):2749-57. pmid: 8188468
Shetty R, Arora V, Jayadev C, Nuijts RM, Kumar M, Puttaiah NK, et al. Repeatability and agreement of three Scheimpflug-based imaging systems for measuring anterior segment parameters in keratoconus. Invest Ophthalmol Vis Sci. 2014;55(8):5263-8. doi: 10.1167/iovs.14-15055 pmid: 25074774
Wang L, Shirayama M, Koch DD. Repeatability of corneal power and wavefront aberration measurements with a dual-Scheimpflug Placido corneal topographer. J Cataract Refract Surg. 2010;36(3):425-30. doi: 10.1016/j.jcrs.2009.09.034 pmid: 20202540
Aramberri J, Araiz L, Garcia A, Illarramendi I, Olmos J, Oyanarte I, et al. Dual versus single Scheimpflug camera for anterior segment analysis: Precision and agreement. J Cataract Refract Surg. 2012;38(11):1934-49. doi: 10.1016/j.jcrs.2012. 06.049 pmid: 22995705
Rabinowitz YS. Videokeratographic indices to aid in screening for keratoconus. J Refract Surg. 1995;11(5):371-9. pmid: 8528916
Wilson SE, Klyce SD. Advances in the analysis of corneal topography. Surv Ophthalmol. 1991;35(4):269-77. pmid: 2011820
Kim EJ, Montes de Oca I, Wang L, Weikert MP, Koch DD, Khandelwal SS. Repeatability of posterior and total corneal curvature measurements with a dual Scheimpflug-Placido tomographer. J Cataract Refract Surg. 2015;41(12):2731-8. doi: 10.1016/j.jcrs.2015.07.035 pmid: 26796454
Mauger TF, Mahmoud AM, Roberts CJ, Chheda LV, Kuennen RA, Hendershot AJ, et al. Comparison of Placido, Scheimpflug and Combined Dual Scheimpflug-Placido Technologies in Evaluating Anterior and Posterior CLMI, SimK's as well as Kmax, in Keratoconic and Postrefractive Surgery Ectasia. Int J Keratoconus Ectatic Corneal Dis. 2012;1(1):44-52. doi: 10.5005/jp-journals-10025-1008
Mahmoud AM, Nunez MX, Blanco C, Koch DD, Wang L, Weikert MP, et al. Expanding the cone location and magnitude index to include corneal thickness and posterior surface information for the detection of keratoconus. Am J Ophthalmol. 2013;156(6):1102-11. doi: 10.1016/j.ajo.2013.07.018 pmid: 24075426
Maeda N, Klyce SD, Smolek MK. Neural network classification of corneal topography. Preliminary demonstration. Invest Ophthalmol Vis Sci. 1995;36(7):1327-35. pmid: 7775110
Savini G, Barboni P, Carbonelli M, Hoffer KJ. Accuracy of a dual Scheimpflug analyzer and a corneal topography system for intraocular lens power calculation in unoperated eyes. J Cataract Refract Surg. 2011;37(1):72-6. doi: 10.1016/j.jcrs. 2010.08.036 pmid: 21183101
Sadoughi MM, Feizi S, Delfazayebaher S, Baradaran-Rafii A, Einollahi B, Shahabi C. Corneal Changes After Collagen Crosslinking for Keratoconus Using Dual Scheimpflug Imaging. J Ophthalmic Vis Res. 2015;10(4):358-63. doi: 10.4103/2008-322X.176894 pmid: 27051478
Fahd DC, Cherfan CG, Raad C, Asouad M, Awwad ST. Assessment of anterior and posterior corneal indices using two Scheimpflug analyzers. Arq Bras Oftalmol. 2014;77(1):17-20. pmid: 25076367
Menassa N, Kaufmann C, Goggin M, Job OM, Bachmann LM, Thiel MA. Comparison and reproducibility of corneal thickness and curvature readings obtained by the Galilei and the Orbscan II analysis systems. J Cataract Refract Surg. 2008;34(10):1742-7. doi: 10.1016/j.jcrs.2008.06.024 pmid: 18812127
Baradaran-Rafii A, Motevasseli T, Yazdizadeh F, Karimian F, Fekri S, Baradaran-Rafii A. Comparison between Two Scheimpflug Anterior Segment Analyzers. J Ophthalmic Vis Res. 2017;12(1):23-9. doi: 10.4103/jovr.jovr_104_16 pmid: 28299003
Salouti R, Nowroozzadeh MH, Zamani M, Ghoreyshi M, Salouti R. Comparison of anterior chamber depth measurements using Galilei, HR Pentacam, and Orbscan II. Optometry. 2010;81(1):35-9. doi: 10.1016/j.optm.2009.04.100 pmid: 20004876
Salouti R, Nowroozzadeh MH, Zamani M, Fard AH, Niknam S. Comparison of anterior and posterior elevation map measurements between 2 Scheimpflug imaging systems. J Cataract Refract Surg. 2009;35(5):856-62. doi: 10.1016/j.jcrs. 2009.01.008 pmid: 19393884
de Jong T, Sheehan MT, Koopmans SA, Jansonius NM. Posterior corneal shape: Comparison of height data from 3 corneal topographers. J Cataract Refract Surg. 2017;43(4):518-24. doi: 10.1016/j.jcrs.2017.03.021 pmid: 28532938
Lee YW, Choi CY, Yoon GY. Comparison of dual rotating Scheimpflug-Placido, swept-source optical coherence tomography, and Placido-scanning-slit systems. J Cataract Refract Surg. 2015;41(5):1018-29. doi: 10.1016/j.jcrs.2014. 08.040 pmid: 26049835
Park SH, Choi SK, Lee D, Jun EJ, Kim JH. Corneal thickness measurement using Orbscan, Pentacam, Galilei, and ultrasound in normal and post-femtosecond laser in situ keratomileusis eyes. Cornea. 2012;31(9):978-82. doi: 10.1097/ ICO.0b013e31823d03fc pmid: 22699561
Huang J, Savini G, Wang C, Lu W, Gao R, Li Y, et al. Precision of corneal thickness measurements obtained using the scheimpflug-placido imaging and agreement with ultrasound pachymetry. J Ophthalmol. 2015;2015:328798. doi: 10.1155/ 2015/328798 pmid: 25810919
Crawford AZ, Patel DV, McGhee CN. Comparison and repeatability of keratometric and corneal power measurements obtained by Orbscan II, Pentacam, and Galilei corneal tomography systems. Am J Ophthalmol. 2013;156(1):53-60. doi: 10.1016/j.ajo.2013.01.029 pmid: 23540708
Hsieh YH, Weng TH, Chou YC, Wu KL, Liang CM, Tai MC. Agreement of post-LASIK corneal power and corneal thickness measurements by pentacam and GALILEI corneal tomography systems. J Chin Med Assoc. 2018. doi: 10.1016/j.jcma. 2018.07.005 pmid: 30268641
Anayol MA, Guler E, Yagci R, Sekeroglu MA, Ylmazoglu M, Trhs H, et al. Comparison of central corneal thickness, thinnest corneal thickness, anterior chamber depth, and simulated keratometry using galilei, Pentacam, and Sirius devices. Cornea. 2014;33(6):582-6. doi: 10.1097/ICO. 0000000000000119 pmid: 24763122
Jahadi Hosseini HR, Katbab A, Khalili MR, Abtahi MB. Comparison of corneal thickness measurements using Galilei, HR Pentacam, and ultrasound. Cornea. 2010;29(10):1091-5. doi: 10.1097/ICO.0b013e3181cf98e5 pmid: 20628301
Jafarinasab MR, Shirzadeh E, Feizi S, Karimian F, Akaberi A, Hasanpour H. Sensitivity and specificity of posterior and anterior corneal elevation measured by orbscan in diagnosis of clinical and subclinical keratoconus. J Ophthalmic Vis Res. 2015;10(1):10-5. doi: 10.4103/2008-322X.156085 pmid: 26005546
Hwang ES, Perez-Straziota CE, Kim SW, Santhiago MR, Randleman JB. Distinguishing Highly Asymmetric Keratoconus Eyes Using Combined Scheimpflug and Spectral-Domain OCT Analysis. Ophthalmology. 2018;125(12):1862-71. doi: 10.1016/j. ophtha.2018.06.020 pmid: 30055838
Belin MW, Khachikian SS. New devices and clinical implications for measuring corneal thickness. Clin Exp Ophthalmol. 2006;34(8):729-31. doi: 10.1111/j.1442-9071.2006. 01395.x pmid: 17073893
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