Corneal biomechanics and tomographic parameters for different corneal diameters in Chinese patients with myopia

To compare the distribution characteristics of corneal biomechanics and tomographic parameters for different corneal diameter (CD) in Chinese patients. A retrospective cohort study of 403 consecutive patients without ectasia who underwent binocular corneal refractive surgery and were followed up for more than 2 years. All patients underwent a preoperative corneal tomography using Pentacam and corneal biomechanics using Corvis-ST. Significant differences were observed in the Stiffness parameter at first applanation (SP-A1), Ambrosio relational thickness to the horizontal profile (ARTh), Belin/Ambrosio enhanced ectasia total deviation index (BAD-D), Corvis Biomechanical Index (CBI), and Tomographic and Biomechanical Index (TBI) indicators among the CD ≤ 11.0 mm, 11.0 mm < CD ≤ 11.5 mm, 11.5 mm < CD < 12.0 mm, and CD ≥ 12.0 mm groups (all P < 0.05). CD was negatively correlated with BAD-D, CBI, and TBI (r = -0.475, -0.269 and − 0.237, all P < 0.05); Multiple linear regression analysis showed that TBI was negatively correlated with CD, SP-A1, and ARTh (R2 = 0.12, p<0.001). CD may correlated with the biomechanical results, where smaller CD is often associated with higher BAD, CBI, and TBI values. CD-specific thresholds for biomechanical indices may reduce overdiagnosis of keratoconus in small corneas.