角膜生物力学与光密度相关性研究

目的:探究角膜生物力学与角膜光密度的相关性。方法:前瞻性研究。选取2019-03/06在云南省第二人民医院拟行角膜屈光手术术前检查的患者为研究对象。采用Pentacam HR眼前节分析系统进行角膜光密度测量,以角膜顶点为中心,分为0~2mm、> 2~6mm、> 6~10mm直径范围3个区域,以角膜厚度分为前、中、后3层。选取Pentacam HR中角膜最薄点厚度值纳入研究。采用Corvis ST角膜生物力学分析仪测量,相关参数包括第一次压平的长度(AP1L)和速率(AP1V)、第2次压平的长度(AP2L)和速率(AP2V)、最大凹陷时顶点距离(PD)、曲率半径(HCR)和形变幅度(DA)。运用Pentacam&Corvis ST生物力学联合诊断平台软件综合分析检查结果,得出综合角膜生物力学参数(CBI)以及其它独立参数包括硬度参数(SP)、综合半径(IR)、Ambrosio相关厚度-水平方向(ARTh)、形变幅度比(DAR)。各区域光密度间差异采用方差分析,角膜生物力学各项参数与各区域光密度的相关性采用Pearson或Spearman分析。结果:不同直径范围、不同层面间光密度有差异(F=35.101,P<0.01;F=1002.897,P<0.01),CBI与独立生物力学参数中AP2L、AP2V、PD、DA、SP、IR、ARTh、DAR具有相关性(rs=-0.502,P<0.01;rs=-0.457,P=0.001;rs=0.428,P=0.002;rs=0.539,P<0.01;rs=-0.687,P<0.01;rs=0.716,P<0.01;rs=-0.728,P<0.01;rs=0.750,P<0.01)。CBI与角膜0~2mm范围内光密度呈正相关(r=0.343,P=0.015)。0~2mm范围内光密度与独立生物力学参数中AP2L、IR、ARTh、DAR有相关性(rs=-0.298,P=0.035;rs=0.368,P=0.009;rs=-0.419,P=0.002;rs=0.493,P<0.01)。结论:角膜中央区域光密度与角膜生物力学具有显著的关联,临床中可以通过光密度和生物力学对角膜健康状况进行综合评价。

Correlation between corneal biomechanics and corneal densitometry

AIM: To explore the correlation between corneal biomechanics and corneal densitometry.

METHODS: Prospective study. Patients who examined before corneal refractive surgery in the Second People''s Hospital of Yunnan Province from March 2019 to June 2019 were selected as research objects. Pentacam HR system was used to evaluate corneal densitometry. The corneal was divided into three areas around the corneal apex with diameters of 0-2mm, >2-6mm, >6-10mm,and the corneal thickness was divided into anterior, middle and posterior layers. The thinnest point thickness of cornea in Pentacam HR was selected to be included in the study. Corvis ST was used to measure the biomechanical parameters, including the first applanation length(AP1L)and applanation velocity(AP1V),the second applanation length(AP2L)and applanation velocity(AP2V),the highest concavity peak distance(PD),highest concavity radius(HCR)and deformation amplitude(DA). Pentacam & Corvis ST comprehensive diagnostic platform software was used to comprehensively analyze the examination results and obtain comprehensive corneal biomechanical parameters(CBI), as well as other independent parameters including stiffness parameters(SP), integrated radius(IR), Ambrosio relational thickness-horizontal(ARTh)and deformation amplitude ratio(DAR). Variance analysis was used for the difference of corneal densitometry in each region, the correlation between corneal biomechanical parameters and corneal densitometry was analyzed by Pearson or Spearman.

RESULTS: The difference of optical density between different diameter ranges and different layers was statistically significant(F=35.101, P<0.01; F=1002.897, P<0.01), CBI was correlated with AP2L,AP2V,PD,DA,SP,IR,ARTh and DAR in the independent biomechanical parameters(r_s= -0.502, P<0.01; r_s=-0.457, P=0.001; r_s=0.428, P=0.002; r_s=0.539, P<0.01; r_s=-0.687, P<0.01; r_s=0.716, P<0.01; r_s=-0.728, P<0.01; r_s=0.750, P<0.01). CBI was positively correlated with optical density within the range of 0-2mm(r=0.343, P=0.015). The corneal densitometry within a range of 0-2mm is correlated with AP2L, IR, ARTH and DAR in independent biomechanical parameters(r_s=-0.298, P=0.035; r_s=0.368, P=0.009; r_s=-0.419, P=0.002; r_s=0.493, P<0.01).

CONCLUSION: There is a correlation between corneal biomechanics and corneal densitometry in the central region of cornea, which has a more significant correlation with the biomechanics.