Detection of Keratoconus With a New Corvis Biomechanical Index Optimized for Chinese Populations

center dot PURPOSE: The aim of this study was to introduce an optimized version of the Corvis Biomechanical Index for Chinese populations (cCBI). center dot DESIGN: Retrospective, multicenter clinical validity en-hancement study. center dot METHODS: Patients were included from 7 clinics in Beijing, Shenyang, Guangzhou, Shanghai, Wenzhou, Chongqing, and Tianjin, China. Logistic regression was used to optimize the values of the constants of the CBI, based on database 1 as the development dataset (6 of 7 clinics), to create a new version of the index named cCBI. The factors of the CBI (A1Velocity, ARTh, Stiff-ness Parameter-A, DARatio2mm, and Inverse Integrated Radius) and the cutoff value were kept the same (0.5). With the formation of cCBI determined, it was validated on database 2 (1 of the 7 clinics). center dot RESULTS: Two thousand four hundred seventy-three patients (healthy and keratoconus) were included. In database 2, the area under the curve of the cCBI was 0.985 with 93.4% specificity and 95.5% sensitivity. In the same dataset, the original CBI produced an area under the curve of 0.978 with 68.1% specificity and 97.7% sen-sitivity. There was a statistically significant difference be-tween the receiver operating characteristic curve of cCBI and CBI (De Long P = .0009) center dot CONCLUSION: The new cCBI for Chinese patients was shown to be statistically significantly better when compared with CBI to separate healthy from kera-toconic eyes. The presence of an external validation dataset confirms this finding and suggests the use of cCBI in everyday clinical practice to aid in the di-agnosis of keratoconus in patients who are of Chi-nese ethnicity. (Am J Ophthalmol 2023;252: 182-187. (c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ))

Automated summary

The aim of this study was to introduce an optimized version of the Corvis Biomechanical Index (cCBI) for Chinese populations. By optimizing the constants of the CBI using logistic regression, a new version of the index named cCBI was created. The validation results showed that cCBI was statistically significantly better than CBI in separating healthy from keratoconic eyes in Chinese patients.