Purpose: To determine the diagnostic value of the anterior segment optical coherence tomography (AS-OCT) indices in differentiating normal from ectatic corneas. Material and Methods: Two groups of patients—with corneal ectasia and normal controls were compared. Each group consists of 80 eyes of 43 age and sex-matched patients. All of them underwent corneal topography with OCULUS Keratograph 5M and corneal pachymetry with AS-OCT with RTVue-100. The indices generated by the AS-OCT pachymetric scans were analyzed. Results: There was a statistically significant difference for all the examined indices between the two groups with p values <0.001 and a confidence interval of 95%. The minimal corneal thickness (Min) was the best performing index according to the ROC analysis with an area under the curve of 0.976 and a combination of sensitivity and specificity of 0.925 and 0.911 respectively, and a “cut-off” value of 484 microns, followed by the indices of focal thinning—Min-Med and Min-Max with an area under the curve of 0.973 and 0.971 and sensitivity/specificity of 0.938/0.962 and 0.938/0.937 respectively. The rest of the examined parameters had an area under the curve in the range between 0.950 for the central corneal thickness and 0.814 for the outer superior segment. Conclusion: The anterior segment OCT indices showed excellent capability in differentiating ectatic from normal corneas.
References
[1]
Krachmer, J.H., Feder, R.S. and Belin, M.W. (1984) Keratoconus and Related Nonin-flammatory Corneal Thinning Disorders. Survey of Ophthalmology, 28, 293-322. https://doi.org/10.1016/0039-6257(84)90094-8
[2]
Rabinowitz, Y.S. (1998) Keratoconus. Survey of Ophthalmology, 42, 297-319. https://doi.org/10.1016/S0039-6257(97)00119-7
[3]
Belin, M.W., Asota, I.M., Ambrosio, R. and Khachikian, S.S. (2011) What’s in a Name: Keratoconus, Pellucid Marginal Degeneration, and Related Thinning Disorders. American Journal of Ophthalmology, 152, 157-162.E1. https://doi.org/10.1016/j.ajo.2011.03.028
[4]
Varssano, D., Kaiserman, I. and Hazarbassanov, R. (2004) Topographic Patterns in Refractive Surgery Candidates. Cornea, 23, 602-607. https://doi.org/10.1097/01.ico.0000121699.74077.f0
[5]
Holladay, J.T. (2009) Keratoconus Detection Using Corneal Topography. Journal of Refractive Surgery, 25, S958-S962. https://doi.org/10.3928/1081597X-20090915-11
[6]
Vinciguerra, R., Ambrósio, R., Elsheikh, A., Roberts, C.J., Lopes, B., Morenghi, E., et al. (2016) Detection of Keratoconus with a New Biomechanical Index. Journal of Refractive Surgery, 32, 803-811. https://doi.org/10.3928/1081597X-20160629-01
[7]
Ali, N.Q., Patel, D.V. and McGhee, C.N.J. (2014) Biomechanical Responses of Healthy and keraToconic Corneas Measured Using a Noncontact Scheimpflug-Based Tonometer. Investigative Ophthalmology and Visual Science, 55, 3651-3659. https://doi.org/10.1167/iovs.13-13715
[8]
Shah, S., Laiquzzaman, M., Bhojwani, R., Mantry, S. and Cunliffe, I. (2007) Assessment of the Biomechanical Properties of the Cornea with the Ocular Response Analyzer in Normal and Keratoconic Eyes. Investigative Ophthalmology and Visual Science, 48, 3026-3031. https://doi.org/10.1167/iovs.04-0694
[9]
Fontes, B.M., Ambrósio, R., Jardim, D., Velarde, G.C. and Nosé, W. (2010) Corneal Biomechanical Metrics and Anterior Segment Parameters in Mild Keratoconus. Ophthalmology, 117, 673-679. https://doi.org/10.1016/j.ophtha.2009.09.023
[10]
Gomes, J.A.P., Tan, D., Rapuano, C.J., Belin, M.W., Ambrósio Jr, R., Guell, J.L., et al. (2015) Global Consensus on Keratoconus and Ectatic Diseases. Cornea, 34, 359-369. https://doi.org/10.1097/ICO.0000000000000408
[11]
Siebelmann, S., Scholz, P., Sonnenschein, S., Bachmann, B., Matthaei, M., Cursiefen, C., et al. (2018) Anterior Segment Optical Coherence Tomography for the Diagnosis of Corneal Dystrophies According to the IC3D Classification. Survey of Ophthalmology, 63, 365-380. https://doi.org/10.1016/j.survophthal.2017.08.001
[12]
See, J.L.S., Chew, P.T.K., Smith, S.D., Nolan, W.P., Chan, Y.-H., Huang, D., et al. (2007) Changes in Anterior Segment Morphology in Response to Illumination and after Laser Iridotomy in Asian Eyes: An Anterior Segment OCT Study. British Journal of Ophthalmology, 91, 1485-1489. https://doi.org/10.1136/bjo.2006.113654
[13]
Lee, K.S., Sung, K.R., Kang, S.Y., Cho, J.W., Kim, D.Y. and Kook, M.S. (2011) Residual Anterior Chamber Angle Closure in Narrow-Angle Eyes Following Laser Peripheral Iridotomy: Anterior Segment Optical Coherence Tomography Quantitative Study. Japanese Journal of Ophthalmology, 55, 213-219.
[14]
Nakano, N., Hangai, M., Nakanishi, H., Inoue, R., Unoki, N., Hirose, F., et al. (2010) Early Trabeculectomy Bleb Walls on Anterior-Segment Optical Coherence Tomography. Graefe’s Archive for Clinical and Experimental Ophthalmology, 248, 1173-1182. https://doi.org/10.1007/s00417-010-1311-3
[15]
Krema, H., Santiago, R.A., Gonzalez, J.E. and Pavlin, C.J. (2013) Spectral-Domain Optical Coherence Tomography versus Ultrasound Biomicroscopy for Imaging of Nonpigmented Iris Tumors. American Journal of Ophthalmology, 156, 806-812.E1. https://doi.org/10.1016/j.ajo.2013.05.025
[16]
Bianciotto, C., Shields, C.L., Guzman, J.M., Romanelli-Gobbi, M., Mazzuca Jr., D., Ross Green, W., et al. (2011) Assessment of Anterior Segment Tumors with Ultrasound Biomicroscopy versus Anterior Segment Optical Coherence Tomography in 200 Cases. Ophthalmology, 118, 1297-1302. https://doi.org/10.1016/j.ophtha.2010.11.011
[17]
Sun, G.H., Li, S.X., Gao, H., Zhang, W.B., Zhang, M.A. and Shi, W.Y. (2012) Clinical Observation of Removal of the Necrotic Corneal Tissue Combined with Conjunctival Flap Covering Surgery under the Guidance of the AS-OCT in Treatment of Fungal Keratitis. International Journal of Ophthalmology, 5, 88-91.
[18]
Hixson, A., Blanc, S. and Sowka, J. (2014) Monitoring Keratitis Resolution with Optical Coherence Tomography. Optometry and Vision Science, 91, S40-S45. https://doi.org/10.1097/OPX.0000000000000189
[19]
Soliman, W., Fathalla, A.M., El-Sebaity, D.M. and Al-Hussaini, A.K. (2013) Spectral Domain Anterior Segment Optical Coherence Tomography in Microbial Keratitis. Graefe’s Archive for Clinical and Experimental Ophthalmology, 251, 549-553. https://doi.org/10.1007/s00417-012-2086-5
[20]
Temstet, C., Sandali, O., Bouheraoua, N., Hamiche, T., Galan, A., El Sanharawi, M., et al. (2015) Corneal Epithelial Thickness Mapping Using Fourier-Domain Optical Coherence Tomography for Detection of form Fruste Keratoconus. Journal of Cataract and Refractive Surgery, 41, 812-820. https://doi.org/10.1016/j.jcrs.2014.06.043
[21]
Rocha, K.M., Perez-Straziota, C.E., Stulting, R.D. and Randleman, J.B. (2013) SD-OCT Analysis of Regional Epithelial Thickness Profiles in Keratoconus, Postoperative Corneal Ectasia, and Normal Eyes. Journal of Refractive Surgery, 29, 173-179. https://doi.org/10.3928/1081597X-20130129-08
[22]
Uçakhan, Ö.Ö., Çetinkor, V., Özkan, M. and Kanpolat, A. (2011) Evaluation of Scheimpflug Imaging Parameters in Subclinical Keratoconus, Keratoconus, and Normal Eyes. Journal of Cataract and Refractive Surgery, 37, 1116-1124. https://doi.org/10.1016/j.jcrs.2010.12.049
[23]
Muftuoglu, O., Ayar, O., Hurmeric, V., Orucoglu, F. and Kilic, I. (2015) Comparison of Multimetric D Index with Keratometric, Pachymetric, and Posterior Elevation Parameters in Diagnosing Subclinical Keratoconus in Fellow Eyes of Asymmetric Keratoconus Patients. Journal of Cataract and Refractive Surgery, 41, 557-565. https://doi.org/10.1016/j.jcrs.2014.05.052
[24]
Miháltz, K., Kovács, I., Takács, á. and Nagy, Z.Z. (2009) Evaluation of Keratometric, Pachymetric, and Elevation Parameters of Keratoconic Corneas with Pentacam. Cornea, 28, 976-980. https://doi.org/10.1097/ICO.0b013e31819e34de
[25]
Ramos, I., Correia, F.F., Lopes, B., Salomão, M.Q. and Correa, R.O. (2012) Topometric and Tomographic Indices for the Diagnosis of Keratoconus. International Journal of Keratoconus and Ectatic Corneal Diseases, 1, 92-99. https://doi.org/10.5005/jp-journals-10025-1018
[26]
Li, Y., Meisler, D.M., Tang, M., Lu, A.T.H., Thakrar, V., Reiser, B.J., et al. (2008) Keratoconus Diagnosis with Optical Coherence Tomography Pachymetry Mapping. Ophthalmology, 115, 2159-2166. https://doi.org/10.1016/j.ophtha.2008.08.004
[27]
Reinstein, D.Z., Gobbe, M., Archer, T.J., Silverman, R.H. and Coleman, J. (2010) Epithelial, Stromal, and Total Corneal Thickness in Keratoconus: Three-Dimensional Display with Artemis Very-High Frequency Digital Ultrasound. Journal of Refractive Surgery, 26, 259-271. https://doi.org/10.3928/1081597X-20100218-01
[28]
Qin, B., Chen, S., Brass, R., Li, Y., Tang, M., Zhang, X., et al. (2013) Keratoconus Diagnosis with Optical Coherence Tomography-Based Pachymetric Scoring System. Journal of Cataract and Refractive Surgery, 39, 1864-1871. https://doi.org/10.1016/j.jcrs.2013.05.048
