Assessing the effect of capsular bag on the biomechanics of the lens using Optical Coherence Elastography

Abstract

The biomechanical properties of the crystalline lens are essential for altering and adjusting the focus of light entering the eye by process called accommodation. During this process, the capsular bag surrounding the lens presses upon the lens and molds it into the required shape. Yet, the influence of the characteristics of the capsule on the lens biomechanics hasn’t been fully investigated. In this study, the lens elasticity difference before and after removal of the capsular bag was assessed using phase-sensitive optical coherence elastography (OCE) coupled with acoustic radiation force (ARF) based excitation. With the ARF pulse burst of 1 ms, OCE measurements were undertaken on seven dissected porcine eye lenses before and after removal of the capsular bag. The ARF excitation was focused on the anterior pole of the lens, and two orthogonal M-B mode scans were performed for each sample before and after removal of the lens capsule. The resulting wave propagation speed, Vs, in the lens with intact capsule (Vs,mean= 2.60 ± 0.21 m/s) was found to be significantly higher (p <.001) than after the capsule was removed (Vs,mean= 1.14 ± 0.15 m/s). Also, the shape measurements indicate the difference in the geometry of the lens with and without capsule. The findings indicate that the capsule is a key ocular component that determines the stiffness and structural integrity of the lens.
Keywords: lens capsule, biomechanics, acoustic radiation force, optical coherence elastography

Link to presentation: https://uofh-my.sharepoint.com/:p:/g/personal/klarin_cougarnet_uh_edu/EYUzd1exVPlFi86-8tCmVJQBTwGzOL6lQteDDfQsXo7rmg?e=LBeaVR

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Taye Mekonnen
University of Houston
United States

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