正常角膜生物力学参数与角膜直径的相关性分析

目的　探究正常角膜生物力学指标与角膜直径的相关性。方法　前瞻性研究。选取2019年6月至2020年4月在云南省第二人民医院拟行角膜屈光手术的患者215例（215眼）为研究对象，中央角膜厚度为520~550 μm。所有患者均行Pentacam HR检测角膜水平直径（白到白）（HWTW）、角膜扩张综合偏差分析指数（BAD-D）；Corvis ST检测第一次压平硬度指数（SPA1）、综合半径（IR）、水平方向Ambrosio相关厚度（ARTh）、角膜顶点2 mm位置间形变幅度比（DAR）、角膜生物力学指数（CBI），计算综合分析指数（TBI）。将HWTW与其他参数进行相关性分析。结果　共入选患者215例（215眼），年龄（22.96±6.62）岁，其中HWTW≤11.0 mm者52眼，HWTW为11.1~11.5 mm者57眼，HWTW为11.6~12.0 mm者55眼，HWTW>12.0 mm者51眼。角膜直径为10.50~12.60（11.56±0.54）mm，CBI为0.00~0.98［0.09（0.01， 0.41）］，BAD-D为-0.04~2.36（1.05±0.51），TBI为0.00~0.73［0.23（0.03， 0.35）］。HWTW与SPA1、ARTh均呈正相关（r=0.151，P=0.027；r=0.584，P=0.000），与CBI、BAD-D、TBI均呈负相关（r=-0.437、-0.627、-0.338，均为P=0.000）。结论　CBI、BAD-D、TBI与角膜直径具有显著相关性，随着角膜直径的减小，CBI、BAD-D、TBI值增大，在角膜直径相对较小的中国人群中，应该充分考虑角膜直径对检测结果的影响。

Correlation between corneal biomechanical parameters and corneal diameter

Objective　To investigate the correlation between normal corneal biomechanical parameters and corneal diameter. Methods　A total of 215 patients (215 eyes) who received corneal refractive surgery in the Second People’s Hospital of Yunnan Province from June 2019 to April 2020 were enrolled in this prospective study. Their central corneal thickness was between 520 and 550 μm. Pentacam HR was performed to detect patients’ horizontal white-to-white (HWTW) and Belin/Ambrosio deviation (BAD-D). Corvis ST was performed to detect patients’ stiffness parameter at the first applanation (SPA1), integrated radius (IR), Ambrosio relational thickness to the horizontal profile (ARTh), deformation-amplitude ratio max 2 mm (DAR 2 mm), and Corvis biomechanical index (CBI). Tomographic and biomechanical index (TBI) was also measured. The correlation between HWTW and other parameters was analyzed. Results　Among the 215 patients (215 eyes) ［age: （22.96±6.62） years old］, 52 eyes had HWTW shorter than 11.0 mm (inclusive), 57 eyes had HWTW longer than 11.1 mm (inclusive) but shorter than 11.5 mm (inclusive), 55 eyes had HWTW longer than 11.6 mm (inclusive) but shorter than 12.0 mm (inclusive), and 51 eyes had HWTW longer than 12.0 mm. Overall, the corneal diameter was 10.50-12.60 (11.56±0.54) mm, CBI was 0.00-0.98 ［0.09 (0.01, 0.41)］, BAD-D was -0.04-2.36 (1.05±0.51), and TBI was 0.00-0.73 ［0.23 (0.03, 0.35)］. HWTW was positively correlated with SPA1 and ARTh (r=0.151, P=0.027; r=0.584, P=0.000) and negatively correlated with CBI, BAD-D and TBI (r=-0.437, P=0.000; r=-0.627, P=0.000; r=-0.338, P=0.000). Conclusion　CBI, BAD-D and TBI are significantly correlated with corneal diameter, which increase with the decrease of corneal diameter. The Chinese population usually has a smaller corneal diameter, so the influence of corneal diameter on these parameters should be considered.