Corvis ST评估近视患者角膜生物力学参数及相关影响因素

Evaluation of corneal biomechanical parameters and related influencing factors in myopic patients by Corvis ST

摘要:

目的：利用可视化角膜生物力学分析仪(Corvis ST)评估不同近视患者角膜生物力学参数的差异及其与眼部其他生物测量参数的相关性。

方法：选取2021-05/12就诊于武汉艾格眼科医院角膜屈光手术科的近视患者132例，均取右眼数据。根据等效球镜度数(SE)将受检者分为中低度近视(-0.50～-6.00D)，高度近视(>-6.00～<-8.00D)，超高度近视(≥-8.00D)。使用Corvis ST测量角膜生物力学形变基础参数包括：包括最大变形幅度(DA)、最大压陷反向曲率半径(HCR)、最大压陷峰距(PD)； 整合参数包括：第一次压平时角膜硬度参数(SP-A1)、综合半径(IR)、2mm处形变幅度的比值(DA ratio)、角膜厚度变异率(ARTh)、Corvis ST生物力学指数(CBI)； 测量眼部其他生物参数包括：SE、眼压(IOP)、眼轴长度(AL)、中央角膜厚度(CCT)、水平角膜直径(WTW)、视神经纤维层厚度(RNFL)。分别比较三组近视患者角膜生物力学参数的差异，并进一步分析三组近视患者角膜生物力学参数与眼部其他生物测量参数及年龄的相关性。

结果：中低度、高度、超高度近视组的SP-A1分别为106.8±16.2、115.6±21.9、106.9±11.5，高度近视组SP-A1高于中低度、超高近视组(均P<0.05)。所有角膜生物力学与CCT均有显著相关性(P<0.01)； 除ARTh外，其余角膜生物力学与IOP均有相关性(P<0.05)； AL与PD呈显著正相关(r=0.270，P=0.002)，与HCR呈较弱的正相关(r=0.177，P=0.043)，与IR呈较弱的负相关(r=-0.183，P=0.036)； WTW与PD、DA、DA ratio均呈正相关(r=0.363，P<0.001； r=0.252，P=0.003； r=0.200，P=0.02)； 角膜生物力学参数与年龄、SE、RNFL均无相关性。

结论：高度近视患者的角膜硬度高于中低度和超高度近视患者，IOP、CCT均为影响角膜生物力学的重要因素。部分生物力学参数和AL、WTW也有一定的相关性，随着眼轴的增长，角膜形变范围PD越大，HCR变大，IR变小，但后两者显著性不强； 角膜直径越大，角膜形变幅度越大。临床中需重视超高度近视患者角膜生物力学参数。

Abstract:

AIM: To assess the differences in corneal biomechanical parameters and their correlation with other ocular biometric parameters in myopic patients using a corneal visualisation scheimpflug technology(Corvis ST).

METHODS: A total of 132 myopic patients who received treatment in the department of refractive surgery of Eyegood Ophthalmic Hospital from May to December 2021 were selected, and the data of right eye were taken. The subjects were classified into low and moderate myopia(-0.50 to -6.00D), high myopia(>-6.00D to <-8.00D), and super high myopia(≥-8.00D)according to the spherical equivalent(SE). The basic parameters of corneal biomechanical deformation measured with Corvis ST included the amount of corneal displacement at highest degree of concavity(DA), radius of curvature at highest concavity(HCR), and distance between the two peaks of the cornea at highest concavity(PD); stiffness parameters at applanation 1(SP-A1), integrated radius(IR), deformation amplitude ratio(DA ratio), Ambrosio relational thickness horizontal(ARTh), Corvis biomechanical index(CBI). Other ocular biometric parameters measured included SE, intraocular pressure(IOP), axial length(AL), central corneal thickness(CCT), white-to-white(WTW)and retinal nerve fiber layer(RNFL)thickness. The differences in corneal biomechanical parameters were compared among the three groups of myopic patients, and the correlation between corneal biomechanical parameters and other ocular biometric parameters and age was further analyzed.

RESULTS: The SP-A1 in the low and moderate, high, and super high myopia groups were 106.8±16.2, 115.6±21.9, and 106.9±11.5, respectively. The SP-A1 in the high myopia group was higher than that in the low and moderate and severe myopia groups(all P<0.05). All corneal biomechanics were significantly correlated with CCT(P<0.01); all corneal biomechanics were correlated with IOP except ARTh(P<0.05); AL was significantly and positively correlated with PD(r=0.270, P=0.002), weakly and positively correlated with HCR(r=0.177, P=0.043), and weakly and negatively correlated with IR(r=-0.183, P=0.036); WTW was positively correlated with PD, DA and DA ratio(r=0.363, P<0.001; r=0.252, P=0.003; r=0.200, P=0.02); there was no correlation between corneal biomechanical parameters and age, SE, and RNFL.

CONCLUSION: Corneal stiffness was higher in high myopia patients than in patients with low to moderate and super high myopia. IOP and CCT were both important factors affecting corneal biomechanics. Some of the biomechanical parameters also have certain correlation with AL and WTW. As the growth of axial length, the PD of corneal deformation and HCR were larger, and IR was smaller, but HCR and IR had little significance; the longer the WTW, the greater the corneal deformation amplitude. In clinical practice, attention should be paid to the corneal biomechanical parameters in patients with super high myopia.