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Research Article
Comparison of the Morphological and Biomechanical Characteristics of Keratoconus, Forme Fruste Keratoconus, and Normal Corneas
Lei Tian
Beijing Tongren Hospital, Capital Medical University
Corresponding Author
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Background: To explore the feasibility of corneal morphological and biomechanical parameters for keratoconus and forme fruste keratoconus diagnosis.
Methods: This case-control study included a total of 517 eyes from 408 keratoconus patients (KC group), 83 eyes from 83 forme fruste keratoconus patients (FFKC group), and 158 eyes from 158 patients with normal corneas (NL group). All subjects underwent routine ophthalmology examinations. Pentacam and Corneal Visualization Scheimpflug Technology were used to obtain corneal morphological and biomechanical parameters. Differences between the groups were compared using receiver operating characteristic (ROC) curve analysis.
Results: Comparison of the NL group with the KC and FFKC groups (P<0.05), and the NL and KC groups alone (P<0.017), revealed statistically significant differences in corneal morphological and biomechanical parameters, except time from the start until the highest concavity (HCT), deflection length of the first applanation (A1 DfL), and deflection length of the second applanation (A2 DfL). Comparison of the NL and FFKC groups revealed 12 significantly different parameters (P<0.017). ROC analysis showed that all corneal morphological parameters and most biomechanical parameters distinguished KC from NL, with an area under the curve (AUC) greater than 0.80, of which Belin-Ambrósio enhanced ectasia total deviation index (BAD-D) and tomographic and biomechanical index (TBI) were most efficient. Except for central astigmatism from the anterior corneal surface (AstigF), the AUC that distinguished FFKC from NL was 0.862. Other parameters distinguished FFKC from NL with low efficiency.
Conclusion: All corneal morphological and most biomechanical parameters are different in KC versus NL, but only a few parameters are different in FFKC versus NL. BAD-D and TBI have the highest efficiency, sensitivity, and specificity for distinguishing KC from NL. The parameters had a low ability to distinguish FFKC from NL. The application of biomechanical instruments to diagnose early keratoconus needs further study.
Keywords
keratoconus, forme fruste keratoconus, corneal morphology, corneal biomechanics
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Research Article
Comparison of the Morphological and Biomechanical Characteristics of Keratoconus, Forme Fruste Keratoconus, and Normal Corneas
Lei Tian
Beijing Tongren Hospital, Capital Medical University
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 15 Dec, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Ophthalmology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: To explore the feasibility of corneal morphological and biomechanical parameters for keratoconus and forme fruste keratoconus diagnosis.
Methods: This case-control study included a total of 517 eyes from 408 keratoconus patients (KC group), 83 eyes from 83 forme fruste keratoconus patients (FFKC group), and 158 eyes from 158 patients with normal corneas (NL group). All subjects underwent routine ophthalmology examinations. Pentacam and Corneal Visualization Scheimpflug Technology were used to obtain corneal morphological and biomechanical parameters. Differences between the groups were compared using receiver operating characteristic (ROC) curve analysis.
Results: Comparison of the NL group with the KC and FFKC groups (P<0.05), and the NL and KC groups alone (P<0.017), revealed statistically significant differences in corneal morphological and biomechanical parameters, except time from the start until the highest concavity (HCT), deflection length of the first applanation (A1 DfL), and deflection length of the second applanation (A2 DfL). Comparison of the NL and FFKC groups revealed 12 significantly different parameters (P<0.017). ROC analysis showed that all corneal morphological parameters and most biomechanical parameters distinguished KC from NL, with an area under the curve (AUC) greater than 0.80, of which Belin-Ambrósio enhanced ectasia total deviation index (BAD-D) and tomographic and biomechanical index (TBI) were most efficient. Except for central astigmatism from the anterior corneal surface (AstigF), the AUC that distinguished FFKC from NL was 0.862. Other parameters distinguished FFKC from NL with low efficiency.
Conclusion: All corneal morphological and most biomechanical parameters are different in KC versus NL, but only a few parameters are different in FFKC versus NL. BAD-D and TBI have the highest efficiency, sensitivity, and specificity for distinguishing KC from NL. The parameters had a low ability to distinguish FFKC from NL. The application of biomechanical instruments to diagnose early keratoconus needs further study.
Figure 1
Figure 1
Figure 2
Figure 2