年龄相关性白内障患者眼轴和角膜曲率对角膜生物力学的影响

目的：探讨应用可视化角膜生物力学分析仪(corneal visualization Scheimpflug technology，Corvis ST)研究不同眼轴长度(axial length，AL)和角膜曲率的老年人角膜生物力学特点。

方法：横断面研究。收集拟接受白内障手术的患者161例297眼，将研究对象按AL值的不同进行分组：22～24mm者190眼，24～26mm者54眼，>26mm者53眼。将AL为22～24mm、K值42～44D之间的研究对象按性别进行分组，男44眼，女44眼； 对AL为22～24mm的研究对象按K值的不同分组：42～44D者88眼，>44D者102眼； 应用可视化角膜生物力学分析仪(Corvis ST)测量角膜生物力学参数，并对不同性别、不同眼轴、不同角膜曲率患者的角膜生物力学参数进行比较性分析，采用单因素方差分析、独立样本t检验等对数据进行统计，并分析各组生物力学参数间的相关性。

结果：男女之间角膜生物力学参数比较，差异无统计学意义(P>0.05)，不同角膜曲率间只有第一压平长度、第二压平长度比较，差异有统计学意义(P<0.05)。不同眼轴长组间：第二压平速度、最大形变幅度、中央角膜厚度、眼压的组间比较，差异有统计学意义(P<0.05)。眼轴与最大形变幅度及眼压呈线性正相关(r=0.429、0.278，P<0.001)，与中央角膜厚度、第二压平速度呈线性负相关(r=-0.291、-0.415，P<0.001)。

结论：角膜曲率和AL可能是使角膜力学属性发生改变的角膜相关参数，角膜厚度会随着眼轴的增长呈现变薄的趋势，角膜也较容易发生形变，而且眼压也会随着眼轴的增长而逐渐增高。

Effects of axial length and corneal curvature on corneal biomechanics in elderly population

AIM:To explore the corneal biomechanical properties of the elderly with different axial length(AL)and corneal curvature by corneal visualization Scheimpflug Technology(Corvis ST).

METHODS: Cross-sectional study. A total of 161 patients(297 eyes)undergoing phacoemulsification were collected in this study. They were divided into 22-24mm, 24-26mm, more than 26mm groups according to axial length(190 eyes, 54 eyes and 53 eyes, respectively). Those of whom axial length was 22-24mm and the corneal curvature was 42-44D were divided into male and female groups(44 eyes and 49 eyes, respectively). Those of whom axial length was 22-24mm were divided into 42-44D group, more than 44D group according to corneal curvature(88 eyes, 102 eyes, respectively). Corvis ST was used to measure the biomechanical parameters of the cornea. The differences in the parameters between different groups were analyzed using the independent-samples t test or one-way analysis of variance and correlation analyses were performed using Pearson correlation analysis.

RESULTS: When comparing the corneal biomechanical parameters, no statistically significant differences were found between male and female groups(P>0.05). The first applanation length and second applanation length among different corneal curvatures were statistically significant(P<0.05). There was statistical significance on the difference of the second applanation velocity, deformation amplitude, central cornea thickness, intraocular pressure in different AL groups(P<0.05). The axial length was positively correlated with deformation amplitude, intraocular pressure(r=0.429, 0.278; P<0.001), but there was negative linear correlation between the patient''s axial length and central cornea thickness, the second applanation velocity(r=-0.291, -0.415; P<0.001).

CONCLUSION: The corneal curvature and ocular axial length may be the factors affecting the corneal biomechanical characteristics. The longer axial length, the thinner corneal thickness, the more easily the corneal is deformed, and with the increase of the axial length, intraocular pressure also increases.