Correlation between corneal biomechanics and corneal densitometry

Abstract:

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.