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Bulgarian Review of Ophthalmology

Topometric indices in patients with corneal ectasia and healthy controls

Angel Atanasov, Marin Atanasov, Marieta Konareva-Kostyaneva

Abstract

Purpose: To determine the diagnostic value of the topometric indices and their role in diagnosing corneal ectasia.

Patients and methods: Using corneal topography OCULUS Keratograph 5M  we examined  80 eyes of 43 patients with corneal ectasia and 86 eye of 43 patients with no signs of corneal disease. We evaluated the topographic maps and the following indices generated by the device: Rv(Vertical radius), Rh (horizontal radius), Кmax, ISV (Index of Surface Variance),  IVA- (Index of Vertical Asymmetry), KI - (Keratoconus Index), CKI- (Center Keratoconus Index ), RMin (Minimal radius),

IHA-(Index of Height Asymmetry), IHD- (Index of Height Decentration), ABR( Aberration). The statistical analyzis was performed by SPSS version 15 and the following test: (Mann–Whitney U test) и ROC (Receiver Operating Characteristic Analysis).

Results: Statistically significant difference was found for all of the examined parameters p<0.001 using 95% confidence interval. The ROC analysis determined area under the curve in the range from 0,992 for ABR and IHA to 0,927 for CKI.

Conclusion: The topometric indices have excellent capabilties in differentiating ectatic from normal corneas.


Keywords

keratoconus, marginal pelucid degeneration, ectasia

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References

Krachmer JH, Feder RS, Belin MW. Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol. 1984;28(4):293-322. doi:10.1016/0039-6257(84)90094-8.

Belin MW, Asota IM, Ambrosio R, Khachikian SS. What’s in a name: Keratoconus, pellucid marginal degeneration, and related thinning disorders. Am J Ophthalmol. 2011;152(2):157-62. doi:10.1016/j.ajo.2011.03.028.

Holladay JT. Keratoconus detection using corneal topography. J Refract Surg. 2009;25(10 Suppl): S958-62. doi:10.3928/1081597x-20090915-11

Klyce SD. Computer-assisted corneal topography. High-resolution graphic presentation and analysis of keratoscopy. Invest Ophthalmol Vis Sci. 1984;25(12):1426-35.

Cavas-Martínez F, de la Cruz Sánchez E, Nieto Martínez J, Fernández Cañavate FJ, Fernández-Pacheco DG. Corneal topography in keratoconus: state of the art. Eye Vis (Lond). 2016;3(1):5. doi:10.1186/s40662-016-0036-8.

Belin MW, Villavicencio OF, Ambrósio RR. Tomographic parameters for the detection of keratoconus: Suggestions for screening and treatment parameters. Eye and Contact Lens. 2014;40(6):326-30. doi:10.1097/ICL.0000000000000077.

Temstet C, Sandali O, Bouheraoua N, Hamiche T, Galan A, El Sanharawi M, et al. Corneal epithelial thickness mapping using Fourier-domain optical coherence tomography for detection of form fruste keratoconus. J Cataract Refract Surg. 2015;41(4):812-20. doi:10.1016/j.jcrs.2014.06.043.

Rocha KM, Perez-Straziota CE, Stulting RD, Randleman JB. SD-OCT analysis of regional epithelial thickness profiles in keratoconus, postoperative corneal ectasia, and normal eyes. J Refract Surg. 2013;29(3):173-9. doi:10.3928/1081597X-20130129-08.

Yang XL, Wang Y, Luo BG, Xu Y, Zhang XF. Corneal epithelial thickness analysis of forme fruste keratoconus with optical coherence tomography. Int J Ophthalmol. 2020;14(1):89-96. doi:10.18240/ijo.2021.01.13.

Fontes BM, Ambrósio R, Jardim D, Velarde GC, Nosé W. Corneal biomechanical metrics and anterior segment parameters in mild keratoconus. Ophthalmology. 2010;117(4): 673-9. doi:10.1016/j.ophtha.2009.09.023.

Shah S, Laiquzzaman M, Bhojwani R, Mantry S, Cunliffe I. Assessment of the biomechanical properties of the cornea with the ocular response analyzer in normal and keratoconic eyes. Invest Ophthalmol Vis Sci. 2007;48(7):3026-31. doi:10.1167/iovs.04-0694.

Labiris G, Giarmoukakis A, Gatzioufas Z, Sideroudi H, Kozobolis V, Seitz B. Diagnostic capacity of the keratoconus match index and keratoconus match probability in subclinical keratoconus. J Cataract Refract Surg. 2014;40(6):999-1005. doi:10.1016/j.jcrs.2013.08.064.

Vinciguerra R, Ambrósio R, Elsheikh A, Roberts CJ, Lopes B, Morenghi E, et al. Detection of keratoconus with a new biomechanical index. J Refract Surg. 2016;32(12):803-10. doi:10.3928/1081597X-20160629-01.

Ali NQ, Patel DV, McGhee CNJ. Biomechanical responses of healthy and keratoconic corneas measured using a noncontact scheimpflug-based tonometer. Invest Ophthalmol Vis Sci. 2014;55(6):3651-9. doi:10.1167/iovs.13-13715.

Elham R, Jafarzadehpur E, Hashemi H, Amanzadeh K, Shokrollahzadeh F, Yekta A et al. Keratoconus diagnosis using Corvis ST measured biomechanical parameters. J Curr Ophthalmol. 2017;29(3):175-81. doi:10.1016/j.joco.2017.05.002.

Ribeiro ALP, Schor P, Allemann N, Chamon W, Campos MS de Q. Reasons not to select patients for corneal refractive surgery. Arq Bras Oftalmol. 2002;65(4):463-6. doi:10.1590/s0004-27492002000400013.

Kanellopoulos AJ, Asimellis G. Revisiting keratoconus diagnosis and progression classification based on evaluation of corneal asymmetry indices, derived from scheimpflug imaging in keratoconic and suspect cases. Clin Ophthalmol. 2013;7:1539-48. doi:10.2147/OPTH.S44741.

Uçakhan ÖÖ, Çetinkor V, Özkan M, Kanpolat A. Evaluation of Scheimpflug imaging parameters in subclinical keratoconus, keratoconus, and normal eyes. J Cataract Refract Surg. 2011;37(6):1116-24. doi:10.1016/j.jcrs.2010.12.049.

Ramos I, Correia FF, Lopes B, Salomão MQ, Correa RO. Topometric and tomographic indices for the diagnosis of keratoconus. Int J Keratoconus Ectatic Corneal Dis. 2012;1(2):92-9. doi:10.5005/jp-journals-10025-1018.

Salomao MQ, Guerra FP, Ramos IC, Jordao LF, Canedo ALC, Valbon BF, et al. Accuracy of topometric indices for distinguishing between keratoconic and normal corneas. Int J Keratoconus Ectatic Corneal Dis. 2013;2(3):108-12. doi:10.5005/jp-journals-10025-1062.

Orucoglu F, Toker E. Comparative analysis of anterior segment parameters in normal and keratoconus eyes generated by scheimpflug tomography. J Ophthalmol. 2015;2015: 925414. doi:10.1155/2015/925414.

Huseynli S, Salgado-Borges J, Alio JL. Comparative evaluation of Scheimpflug tomography parameters between thin non-keratoconic, subclinical keratoconic, and mild keratoconic corneas. Eur J Ophthalmol. 2018;28(5):521-34. doi:10.1177/1120672118760146.




DOI: http://dx.doi.org/10.14748/bro.v66i2.8538

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About The Authors

Angel Atanasov
Medical University of Plovdiv
Bulgaria

Marin Atanasov
Medical University of Plovdiv
Bulgaria

Marieta Konareva-Kostyaneva
Medical University of Plovdiv
Bulgaria

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