Investigation on the strain imaging method for cystoid macular edema using optical coherence tomography

Abstract

Cystoid macular edema (CME) is a major complication of many blinding fundus vascular diseases, and its process is accompanied by complex deformation behavior of the retina. To address the lack of means to evaluate the deformation behavior of the entire retina, a strain imaging method based on CME retinal optical coherence tomography (OCT) radial slice image was developed. The method first removed the rigid body displacement between images by registering the lowest point of the macular central fovea, and then analyzed the maximum strain in the direction of retinal thickness in the images by using the digital image correlation (DIC) method. Subsequently, the spatial distribution of the maximum strain of the retina was obtained by linear interpolation in a spatial coordinate system through coordinate system transformation. Then, the accuracy of strain measurement was verified by uniaxial tensile experiments. The strain imaging results of the two cases showed that the strain concentration region possessed a good correspondence with the spatial location and the degree of deformation of the edema. The proposed method could provide an important tool for the description of the biomechanical process of CME.