Biomechanical Evaluation of Topographically and Tomographically Normal Fellow Eyes of Patients With Keratoconus
- 1 May 2022
- journal article
- research article
- Published by SLACK, Inc. in Journal of Refractive Surgery
- Vol. 38 (5), 318-325
- https://doi.org/10.3928/1081597x-20220225-01
Abstract
To determine the effectiveness of parameters and indices based on biomechanical measures at discriminating fellow eyes with topographically and tomographically normal corneas in patients with keratoconus from normal control corneas. The study included 47 keratoconus suspect eyes, defined as the topographically and tomographically normal fellow eyes of patients with frank keratoconus in the other eye. Eyes were imaged using the Pentacam HR and Corvis ST (both Oculus Optikgeräte GmbH). Fellow eyes were then categorized as topographically/tomographically normal fellow eyes (TNF) and topographically/tomographically borderline fellow eyes (TBF). The ability of each of the Corvis Biomechanical Index (CBI), Tomographic and Biomechanical Index (TBI), stiffness parameter at applanation 1 (SP-A1), and stress-strain index (SSI) at discriminating between normal controls and keratoconus suspects was assessed. The TBI had the best discriminative ability with the greatest area under the receiver operating characteristic (AUROC) curve value of 0.946 for normal controls versus TBF eyes, and 0.824 for normal controls versus TNF eyes. Compared to the TBI AUROC curves, SP-A1 and CBI had AUROC curve values of 0.833 (P = .09) and 0.822 (P = .01) for normal controls versus TBF eyes, respectively, and AUROC curve values of 0.822 (P = .96) and 0.550 (P = .0002) for normal controls versus TNF eyes, respectively. The TBI had the best positive predictive value for TNF and TBF eyes, followed by CBI and SP-A1. The TBI and the purely biomechanical parameter SP-A1 were of moderate utility in distinguishing between normal and keratoconus suspect eyes. In the absence of topographic/tomographic evidence of keratectasia, an independently abnormal biomechanical parameter may suggest an increased risk of ectasia. [J Refract Surg. 2022;38(5):318–325.]Keywords
This publication has 33 references indexed in Scilit:
- In vivo biomechanical mapping of normal and keratoconus corneas.JAMA Ophthalmology, 2015
- Biomechanical Characterization of Keratoconus Corneas Ex Vivo With Brillouin MicroscopyInvestigative Ophthalmology & Visual Science, 2014
- Biomechanics of corneal ectasia and biomechanical treatmentsJournal of Cataract & Refractive Surgery, 2014
- Expanding the Cone Location and Magnitude Index to Include Corneal Thickness and Posterior Surface Information for the Detection of KeratoconusAmerican Journal of Ophthalmology, 2013
- Characterization of age-related variation in corneal biomechanical propertiesJournal of The Royal Society Interface, 2010
- Assessment of Corneal Biomechanical Properties and Their Variation with AgeCurrent Eye Research, 2007
- Corneal Ectasia After Laser In Situ Keratomileusis in Patients Without Apparent Preoperative Risk FactorsCornea, 2006
- Changes in Collagen Orientation and Distribution in Keratoconus CorneasInvestigative Ophthalmology & Visual Science, 2005
- KeratoconusSurvey of Ophthalmology, 1998
- Keratoconus and related noninflammatory corneal thinning disordersSurvey of Ophthalmology, 1984