Abstract
Purpose :
To characterize the birefringence behavior of rabbit cornea using digital photoelasticity technique.
Methods :
Eight rabbit corneas were subjected to intraocular pressure using an in-house designed anterior chamber. Then, the central 11 mm of the cornea was imaged using a polariscope in the transmission mode under white light. The images were captured at 20 mm of Hg pressure. The ten-step phase-shifting technique was employed, and the obtained phase maps were then unwrapped to obtain the full-field corneal birefringence data.
Results :
The rabbit corneas exhibited a saddle-back distribution of isochromatic (contours of constant retardation). These isochromatics form their skeleton around the points of zero retardation, also known as isotropic points in photoelastic literature. The corneal isoclinics (contours of constant angle) were found to be distributed around the isotropic points as they pass through them. Further, the distance between isotropic points was found to vary amongst the tested corneas.
Conclusions :
The birefringence of the cornea shows inter-individual variability yet maintains the saddle-back distribution. Since the isochromatics form their skeleton around isotropic points, it is proposed that the isotropic points are an implication of stable microstructure and curvature under pressure loading. Therefore, it is suggested that tracking the movements of these points during various interventions would be beneficial to clinical practice. However, detailed studies are required to test this hypothesis. Further, the analysis based on digital photoelasticity could be translated into clinical usage due to its simplicity and ability to capture full-field birefringence data.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.