Early Diagnosis of Keratoconus in Chinese Myopic Eyes by Combining Corvis ST with Pentacam.

Purpose: This study was designed to evaluate and compare the sensitivity and specificity of the Belin/Ambrósio Deviation (BADD), Corneal Biomechanical Index (CBI) and Tomographic and Biomechanical Index (TBI) for the diagnosis of keratoconus in Chinese myopic eyes prior to undergoing corneal refractive surgery.

Methods

A total of 125 patients (185 eyes) planned to undergo corneal refractive surgery were selected from the Refractive Center of Beijing Tongren Hospital between December 2017 and December 2018. They were divided into four groups: the normal group, bilateral keratoconus (BK) group, unilateral keratoconus (UK) group, and the forme fruste keratoconus (FFK) group. After determining the BADD, CBI, and TBI for each eye using the Corvis ST combined with Pentacam, the sensitivity and specificity of these three indices in diagnosing keratoconus were analyzed through receiver operating characteristic (ROC) curves.

Results

The TBI exhibited the highest diagnostic efficiency in normal vs. UK (area under the ROC curve [AUROC]: 0.992), normal vs. UK+BK (AUROC: 0.988), normal vs. UK+BK* (*stand randomly selecting one eye of each patient in BK group) (AUROC: 0.982), normal vs. UK+BK+FFK (AUROC: 0.965), and normal vs. UK+BK*+FFK (AUROC: 0.953). The CBI demonstrated the highest diagnostic efficiency in normal vs. FFK (AUROC: 0.897). Finally, the BADD showed the highest diagnostic efficiency in normal vs. BK (AUROC: 0.998) and normal vs. BK* (AUROC: 0.996).

Conclusion

The BADD, CBI, and TBI performed well in diagnosing keratoconus in Chinese myopic eyes. The CBI showed the highest diagnostic efficiency compared with normal for FFK. In addition, the TBI offered the greatest accuracy in detecting keratoconus and FFK eyes vs. the other parameters.